iii. Another head connected with the topographical distribution of

insects relates to their _representation_ of each other. Here we may observe, that some insects represent each other only in their _form_; others also in their _function_; and others in _both_. I shall give some instances of each. In Brazil there is a group of petalocerous beetles (_Chasmodia_), one of the _Rutelidæ_, which in New Holland has a representative, as to _form_, in one of the _Cetoniadæ_ (_Schizorhina_[1514]), which, having soft mandibles, must have a different function:--it is to be observed, however, that these insects appear to approach each other in the series of affinities. Again, the _Carabidæ_ may in the same country be said to have a representative in the remarkable heteromerous genus _Adelium_[1515], which is altogether an analogy. Others are representative only in their _function_. The general function of insects is to remove _nuisances_ and to check _redundances_,--the saprophagous tribes do the one, and the thalerophagous the other. In going from the poles to the line,--in proportion as the heat increases, the quantum of work of both kinds increases; and new forms are either added to the old ones, so as to increase their momentum; or new ones, more powerfully talented, replace the old ones, and act in their stead: thus we see a gradual and interesting change take place in proportion as we approach the maximum of heat and of insect population. At the Cape, the _universal Cicindelæ_ are aided by _Manticora_; in North America, the _Silphidæ_ by a new group, the type of which is _Silpha Americana_ (_Necrophila_, K.MS.); in South America, _Copris_ by _Phanæus_. Again: _Colliuris_ and _Drypta_ of the _old_ world, in the _new_ give place to _Ctenostoma_ and _Agra_. The honey and wax of Europe, Asia, and Africa, is prepared by _bees_ congenerous with our common hive-bee (_Apis_); while in America this genus is not found as a native, but is replaced by _Melipona_ and _Trigona_[1516]; and in New Holland by a still different but undescribed type. The _Melolonthidæ_ and _Rutelidæ_ of the old and new world appear to have their work done in that country by the brilliant and numerous _Anoplognathidæ_. The _Rhipicera_ of Brazil is of a different type from that of New Holland. The singular genus _Cremastocheilus_ of North America has its representative in Africa in _Genuchus_[1517]. The _Lucani_ of the rest of the world give place in New Holland to _Lamprima_ and _Ryssonotus_.--I could produce a much greater number of examples, but these are sufficient to explain my meaning.

* * * * *

Having thus given you some, though an imperfect account, of the _geographical_ distribution of insects, I am next to say something concerning their _local_ distribution in any district, or their favourite _haunts_; a knowledge of which, with respect to those of our own country, is indispensable to the collector.

The surface of a country consists either of mountains, hills and valleys, or of plains. It is diversified by forest, wood, or copse; and watered by rivers, rivulets, lakes, and pools. Those parts that are not clothed with wood are either open or inclosed, forming grassy downs, heaths, pastures, meadows, morasses, and arable land. The soil also is equally various:--we find clay, loam, marl, chalk, vegetable mould, moor, sand, &c. The mountains and hills are either covered with a stratum of soil, or are rocky and bare; the arable lands are divided by living or dead fences, the latter formed of various materials,--or else they are open, and the property only marked out by grassy balks, &c. All these places abound in shrubs and plants; some local, and some generally distributed. But besides the _land_ and its _fresh_ waters, we must look also to the _sea_, and its sandy, pebbly, or rocky shores, and the sea-wrack that is cast up upon them; the _estuaries_ that receive its tides; the brackish waters and saline marshes in its vicinity. All the above places, when opportunity serves, the Entomologist should explore, for in almost all he will find peculiar kinds of insects.

As _mountains_ and _hills_ have usually their own Flora, the insects appropriated to alpine plants can only be met with where the pabulum is found. Here also those northern insects that are impatient of a warmer climate will take their station, if they migrate to the southward[1518]. The predaceous beetles likewise sometimes frequent a mountainous district. _Carabus glabratus_ was first taken by Professor Hooker on Ingleborough; and probably, if the Welsh and Scotch mountains were duly investigated by an Entomologist, many novelties would reward his toils. The _valleys_ and _plains_, especially those of a sunny exposition, abound in insects. When the heat of the atmosphere indisposes you for motion, you will find it no unprofitable or unpleasant employment, lying on the grass, to search for minute beetles, which you will there find coursing about amongst the tufts and roots of the herbage. Thus you may procure many of the _Pselaphidæ_, which you would not otherwise meet with. Even when the grass is grown up, insects are fond of alighting upon its spikes, and thence drop or run to the ground. Should circumstances ever carry you abroad to the steppes or grassy plains of Tartary, or to Hungary, you would find there two or three species of the singular genus _Lethrus_, which burrows in the soil. Every hole is inhabited by a male and female;--from it they issue to attack the plants or vines; and having cut out the heart of a plant, go backwards like a crab with the prize to their burrow. At the time of pairing, sometimes violent battles, encouraged by the female, take place between the male and a stranger of that sex desirous of admission, which cease only with the death or flight of the stranger[1519]. The vicinity and borders of _woods_ generally abound in insects of every Order; and if you proceed, as hereafter directed, will furnish you with numerous prizes, especially of _Lepidoptera_. Here alone you can meet with the purple emperor butterfly (_Apatura Iris_); and if properly equipped you may readily secure him.

The _waters_ you will find nearly as prolific in insects as the land. In them, amongst the beetles, you may expect to meet with _Dytiscus_, _Haliplus_, _Pælobius_, _Hyphydrus_, _Hydroporus_, _Noterus_, _Colymbetes_, and other _Dytiscidæ_; the _Gyrini_, _Hydrophili_, _Hydrænæ_, _Elophori_, &c.: under stones, the _Elmis_; and in the mud, the _Parni_ and _Heteroceri_. Some _Sphæridiadæ_ are also aquatic: I have taken more than once _Cercyon hæmorrhoidale_ from the under side of a piece of wood immersed in a canal[1520]. Even a few of the weevil tribes are to be met with in water. _Lixus paraplecticus_, _Tanysphyrus Lemnæ_, _Bagous atrirostris_, are of this description. A species of _Ceutorhynchus_ of Germar's _third_ family (_C. Natator_ K.) _swims_ well. On aquatic plants you must look for _Helodes_ and the splendid _Donaciæ_, which, living on submerged shoots and roots of these plants in their larva state, continue to attend them when perfect. Amongst the _Eutrech_in_a_[1521],--_Elaphrus_, _Notiophilus_, and _Bembidium_ frequent humid places, as the banks of rivers and ponds; and in such a station, under the roots of _Potentilla anserina_, _Polygonum_, &c. if you should be fortunate enough to find _Omophron limbatum_, which connects the _Eutrech_in_a_ with the _Eunech_in_a_, you will make a valuable addition to the list of British insects. In the waters also you will meet with many Heteropterous _Hemiptera_; as _Gerris_, _Hydrometra_, and _Velia_, and all the _Hydrocorisæ_ or water-bugs. On aquatic plants the larvæ of some _Lepidoptera_ feed, as _Hydrocampa stratiotata_, _potamogata_, &c. Those also of the _Trichoptera_ must be sought for in the water: and if you should feel inclined to see an interesting collection of their very curious _cases_, Mr. Sheppard of Wrabness can gratify your curiosity. Though few or no _Hymenoptera_ frequent this element, vast numbers of _Diptera_ are there alone to be met with in their preparatory state, particularly the gnats. We learn from Humboldt a curious fact with respect to those of South America, or the _Zancudos_; that, with some exceptions, these pests do not frequent those rivers called by the natives _black waters_, but only those which they name _white waters_[1522]. Of the _Aptera_, the genera _Hydrachna_, _Eylaïs_ and _Limnochares_ are purely aquatic. Several spiders will walk over the water; and one species (_Argyroneta aquatica_) inhabits it[1523]. The _stagnant_ waters in your vicinity will produce different species from _running_ ones. Thus _Haliplus elevatus_, &c. inhabits only the _latter_, while the majority of the _Dytiscidæ_ abound most in the _former_: the more minute ones may be sought for with success amongst the duckweed that covers a pool. I do not recollect finding any insect in waters absolutely _salt_[1524]; but _brackish_ waters produce peculiar species: in these only, _Hydræna marina_ occurs; and many of those large-eyed _Cimicidæ_ (_Acanthia_), as _A. saltatoria_, _littoralis_, and _Zosteræ_ occur in places where salt water has been. Latreille observes, that the genus _Pimelia_ is to be met with only where the soil is impregnated with saline particles, or where the species of the genus _Salsola_ abound[1525].

_Heaths_, though they do not afford numerous insects, have their rarities. _Cicindela sylvatica_, _Carabus nitens_ and _arvensis_, frequent them, and are not elsewhere to be seen. _Curculio nebulosus_ is also to be found on them, in places where the turf has been peeled; and some scarce _Lepidoptera_. In their vicinity, in sunny sandy banks, some of the rarer _Ammophilæ_ and _Pompili_ may be taken; and it is here only that I have ever met with _Panurgus_[1526]. _Meadows_ and _pastures_ are not to be neglected. Early in the year, when they are yellow with the blossoms of _Ranunculus bulbosus_, _Leontodon Taraxacum_, &c., many minute beetles, and not a few _Hymenoptera_ and _Diptera_, frequent them. _Morasses_ also have their peculiar insects. In these you will meet with some of the scarcer _Eutrech_in_a_; as _Chlænia holosericea_ and _nigricornis_, _Blethisa multipunctata_, various _Bembidia_, &c. In this kind of district in the Isle of Ely _Aphodius plagiatus_ has been taken, and that scarce and beautiful butterfly _Lycæna Virgaureæ_. Where land is _cultivated_ the Entomologist as well as the farmer may expect a _harvest_. Insects in general are fond of perching on the summit of a blade of grass or corn; and many minute ones may be taken coursing about in the ears of the latter: some to devour the _fungilli_ that infest the grain, as _Phalacrus corruscus_ in _Reticularia Segetum_; others to attack the grain itself, as _Cecidomyia Tritici_; others to destroy these destroyers, as three little parasites belonging to the _Chalcidites_[1527]. But I have already mentioned most of those insects that are to be expected in such situations[1528]: I shall therefore only further observe, that upon _barley_ particularly you will meet with the species of Latreille's genus _Cephus_.

With respect to _soils_, those that are _light_ appear to be most prolific in insects. Warm _sandy_ banks are frequented by _Cicindela campestris_, _Opatrum sabulosum_, _Helops quisquilius_, &c.: in them (when of a southern aspect) _Ammophilæ_, _Pompili_, and numerous _Hymenoptera_ nidificate. _Chalk_ also attracts various insects. Latreille observes, that the _Licini_, _Papilio Cleopatra_, several species of _Dasytes_, and some _Lamiæ_, delight in this kind of soil[1529]:--in my own neighbourhood I have observed _Polyommatus Corydon_ principally in chalk-pits. One of these pits, under a wood in an adjoining parish, has produced me several valuable insects. Here I took _Apion ebeninum_, _Orobitis globosus_, a new species of _Evæsthetus_, several of the rarer _Pselaphidæ_ and _Cholevæ_, and _Chætophorus cretifer_ before noticed[1530]. I do not mean, however, that all these are properly _chalk_ insects; but they fall into these pits, where they are readily discerned, from the contrast of their colours with the whiteness of the chalk. By watching attentively the bottom of one, vast numbers in a warm day may be taken when they fall or are climbing upwards. Of all soils _clay_ offers the fewest inducements to the Entomologist, who will lose both his time and labour in a clay-pit; while in one of sand, chalk, or marl, they will usually not be mispent. _Vegetable earth_ also affords a harbour to various larvæ, and the pupæ of many nightfliers amongst the _Lepidoptera_, by digging in it, especially under trees, may be obtained. Even the bare _rocks_ have their insect frequenters that take shelter in their fissures; and in the early part of your career especially you should always turn over large stones, as beneath them many of the _Harpalidæ_ and other _Eutrech_in_a_ frequently lie hid: and in this situation, both in Suffolk and Sussex, _Lomechusa emarginata_, one of our scarcest _Brachyptera_, has been taken. Old trees also, and planks that have laid long without being moved, often afford a shelter to many of the minute _Coleoptera_; as _Pselaphidæ_, _Aleocharidæ_, _Cryptophagidæ_, _Scymnidæ_, &c. _Live_ fences, especially when the hawthorn is in blossom, and where trees are also intermixed, are attended by innumerable insects of almost every description; and even the black-thorn will present you with one of our most splendid weevils (_Rhynchites Bacchus_). _Dead_ fences are almost as fertile in insects as living ones. In _gates_, _posts_, _rails_, and other _timber_ when felled, the timber-devouring tribes take their station:--between the bark and the wood are the _Bostrichidæ_; in the wood itself, the _Anobidæ_ and the Capricorn beetles. Here also you may meet with many _Hymenoptera_, which either devour timber or nidificate in it,--as the _Siricidæ_, _Chelostoma_, _Trypoxylon_, _Sapyga_, and several _Diptera_. In the decaying hedgestakes and sticks, where the _Sphæria decorticans_ has turned off the bark, you may meet with _Anthribus brevirostris_; with _A. latirostris_, and other beetles, in _S. fraxinea_; and _A. albinus_, which I have more than once captured as it was emerging from the fissure of a gate-post, probably feeds on some internal fungus. The grassy _balks_ that separate open fields usually abound in umbelliferous plants, which are attended by numerous _Hymenoptera_ and _Diptera_, particularly by the various species of the splendid tribe of _Chrysidæ_: and the grassy banks of fences, where the aspect is sunny, are generally bored by a variety of insects of the former Order, to prepare a nest for their young. _Andrenidæ_ and _Nomadidæ_ particularly select this situation, the latter probably depositing their eggs in the burrows of the former[1531]. By watching these places in the spring, you may perhaps have the good fortune to meet with a _Stylops_. It is singular, that some insects choose, for their own residence or that of their young, the hardest and most trodden pathways. Thus, some ants will build their subterranean apartments under gravel walks; and so do many species of the genus _Halictus_[1532], the habits and economy of which have been so ably detailed by M. Walckenaër[1533]: _Cerceris_ also, and other _Hymenoptera_, will choose such places, however public, for the site of their nests or burrows. The ground is so consolidated by the constant foot, that they, probably find such situations spare them a world of labour, and therefore in their choice balance one inconvenience by another.

Though the _sea_ itself, I believe, produces no true _insects_, yet there are many that constantly or occasionally haunt its shores. On the sand-hills of the Norfolk coast I found _Ægialia globosa_ and _Cicindela hybrida_. _Ceutorhynchus horridus_ inhabits thistles that grow near the sea. Under the _Zostera_ and _Fuci_, (cast up both on its beach and the shores of estuaries,) many peculiar species of _Cercyon_, several _Aphodii_, and numerous _Brachyptera_, may often be found. In this situation the rare and singular _Bledius armatus_ has been taken. At certain seasons of the year the beach and environs of the sea are covered by many species of _Coccinella_, which seem to bend their course thither from the inland country, as if they were about to emigrate[1534]. When the weather is fine and the tide begins to retire, at the line of its highest rise I have taken on the eastern coast a variety of insects, and amongst the rest _Anomala Frischii_. The inundations of rivers, except in the depth of winter, always bring a number of these little creatures, which float on the surface on bits of stick, weeds, &c.; and where they deposit these articles when the water begins to subside, you may generally reap a plentiful harvest of various kinds.

You see, now, how varied is the scenery to which the diversion of the Entomologist introduces him; that he is never out of his way: whether on hill or in valley; on upland or plain; on the heath or in the forest; on the land or on the water; in the heart of a country or on its shores;--still his game is within his reach. But in order to enable him to pursue it with greater prospect of success, he must recollect that not only is every face of the country to be explored, but both the _plants_ and the _animals_ that it produces; and that he must not turn with disgust from even the _carcase_ or the _excrement_ of the latter. As numerous species of herbivorous insects feed only on _one_ kind of plant, the Entomologist, when he discovers a scarce one, should examine it with the hope of finding upon it a scarce insect. Sometimes it happens that only a single opportunity occurs in a man's life of seeing certain plants growing wild: such opportunities should never be neglected. Some insects also inhabit a plant in one district or season, and not in another. Thus the most beautiful of the Apions, _A. Limonii_[1535], though the plant it feeds upon usually abounds near the sea, I have discovered only on the northern coast of Norfolk; and another scarcely less beautiful, but more minute (_A. Astragali_[1536]), though I have sought for it year after year, _Astragalus glyciphyllus_ being abundant near me, I never found but once. The blossoms of plants as well as the leaves must be inspected. In those of the rose, the _Cetonia aurata_ is often taken[1537]; and in the bells of the different species of _Campanula_ various bees may be captured enjoying a luxurious repose[1538]. No vegetable productions abound more in insect inhabitants than the _Fungi_. In Agarics several _Diptera_ are to be taken, many _Aleocharæ_, _Oxypori_, &c.; in Boleti, the various species of _Mycetophagus_; in the arboreous ones, and under bark, more than one kind of _Ips_; and in _Auricularia_, as well as _Boletus_, the whole genus _Cis_. Upon _living_ Vertebrate animals you must look for _Pulices_, _Pediculi_, _Nirmi_, _Acari_, and many _Diptera_, as _Œstrus_, _Tabanus_, _Stomoxys_, and the _Pupipara_ of Latreille; and on the garden-snails for that curious genus _Drilus_, and some _Acari_[1539]. The caterpillars and pupæ of _Lepidoptera_, &c. will, as you have heard, furnish you with numerous ichneumons[1540]. On _dead_ animals you will find the various species of _Silphidæ_, _Nitidulidæ_, _Dermestidæ_, _Byrrhidæ_, _Chlolevidæ_, _Staphilinidæ_, _Muscidæ_, &c.; and in excrement, various _Scarabæidæ_, _Histeridæ_, _Aphodiadæ_, _Sphæridiadæ_, the _Brachyptera_ in general, and several _Diptera_[1541]. In putrescent roots and fruits, as the turnip, the cucumber, &c., you may also occasionally meet with rare _Coleoptera_.

* * * * *

I must next say something upon the _seasons_ of insects, and their times of appearance. Those that collect honey and pollen are generally among the first that proclaim the approach of spring; and their appearance may be dated from the blossoming of certain trees and plants of common occurrence. Other plants, accompanied by peculiar insects, blossom later; and so on till we arrive at the autumn. The _earliest_ insect-season commences with the flowering of the _sallow_ (_Salix Caprea_) usually accompanied in the garden by that of the _crocus_ and the _gooseberry_. Then is your time to collect many species of wild bees and _Diptera_ not afterwards to be met with: and various other insects now begin to emerge from their winter-quarters, or are produced from the pupa. _Another_ and later season is marked by the general blossoming of the butter-cup (_Ranunculus bulbosus_), accompanied by the marsh-marygold (_Caltha palustris_) and ladies'-smock (_Cardamine pratensis_); when you may hunt the pastures, meadows, and marshes with success, and take some insects that do not show themselves later. The coprophagous insects are now abundant. Amongst others, _Aphodius testudinarius_, a perfectly _vernal_ species, is now only to be taken, and usually flying. A _third_ insect-season indicated by Flora, and a very prolific one, commences with the blossoming of the _hawthorn_, when you must desert the meads for the inclosures. At this time all nature begins to put on her gayest attire, and all her insect tribes are now on the alert, and fill the air. They are almost universally attracted by the sweet and lovely blossoms of the plant just named: so that by examining them you may entrap some of every Order, and many that during the year will appear no more. Even many of the saprophagous insects will sip nectar from these flowers. The _umbelliferous_ plants proclaim the _fourth_ season of insects, particularly the wild _carrot_ and _parsnip_. You will scarcely ever fail to find, if the weather is genial, _Hymenopterous_ and _Dipterous_ insects of various genera,--especially such as have a _short_ tongue,--engaged in collecting the honey from those plants. Here you may take some of the rarer _Chrysidæ_, _Crabronidæ_, _Cercerides_, &c., and occasionally even _Coleoptera_. The _last_ insect-season may be dated from the general flowering of the _thistle_ tribe. When these are in blossom is the best time of all to collect the _humble-bees_ (_Bombus_[1542]), the leaf-cutter bees (_Megachile_[1543]), and many other _Apiariæ_, which alone by their long tongues can imbibe the honey and collect the pollen of these flowers. The male humble-bees frequent them to the last, and often seem as if they were intoxicated with their sweets.

But perhaps you may prefer considering the whole summer appearance of insects as divided into _three_ principal seasons. This may thus be done. Their _vernal_ season may commence _Florente Caprea_, and end _Florente Oxyacantha_; their _summer_, _Florente Oxyacantha_ and _Florentibus Umbellatis_; their _autumn_, _Florentibus Umbellatis_ and _Florente Carduo_. In the _first_, the number of insects will be daily _increasing_; in the _second_ (which is the harvest of the Entomologist, when his eyes and his hands ought to be every where), they will reach their _utmost complement_; and in the _third_, they will be gradually decreasing in number, till they generally die, or go into winter-quarters. At this time many minute _Diptera_ and Ichneumons take shelter from the weather in the windows of our apartments. These seasons will not always exactly correspond with our usual reckoning, and take place at the same time; since, being regulated by our varying temperature, they will be sometimes sooner and sometimes later, sometimes longer and sometimes shorter. Though I have not named a _brumal_ season, because insects are in winter usually torpid,--yet some, as _Diurnea Novembris_, _Cheimatobia brumata_, and many _Tipulariæ_, even then make their appearance.

If you ask, Whether it be not possible to regulate our Entomological seasons by the appearance of insects themselves? I should answer, that probably this might be done; but that further observations seem wanted to enable us to do it satisfactorily. Perhaps the appearance of _Formica rufa_ beginning the business of the year might form the commencement of one season; the flight of the orange-tip butterfly (_Pontia Cardamines_[1544]), of a second; a third might be indicated by the swarming of _Melolontha vulgaris_; a fourth, by that of _Amphimalla solstitialis_; and the last, by the appearance in numbers of _Aphodius ciliaris_, which in the autumn fills every horse-dropping.

Some insects are so ephemeral, that they are to be found in numbers only for a few days, and then disappear for that season. Of this description are the _Ephemeræ_, much of whose history has been detailed to you. Those of which De Geer has given an account (_E. vulgata_) appeared about the end of May or the beginning of June, and continued about a _fortnight_[1545]; while those which Swammerdam observed did not come forth till the middle of June, and lasted only _three_ days[1546]. The _same_ period distinguished those of which Reaumur has compiled so interesting a history, but they did not show themselves before the middle of August[1547]. My kind friend Mr. Marsham not long before his death copied for me some memoranda he had made with respect to the sudden appearance of _Cercopis bifasciata_. On one occasion the white dress of a lady sitting upon a haycock was covered by these insects; but on the following day the same steps were taken at the same time to procure some, when after the most diligent search not a single one could be found. The same circumstance was observed a few years afterwards by another friend of his. He himself was of opinion that the insects in question were then migrating[1548].

I may here observe, that the London amateurs have particular _seasons_ for collecting _moths_. For the _imago_ they go into the woods in _April_, _May_, _June_, and _October_. For the _larvæ_ they take the beginning of _April_, _June_, the beginning of _July_, and _September_. They dig for _pupæ_ late in _July_, and in _January_ and _February_.

* * * * *

I shall lastly make a few observations upon the _times_ of _action_ and _repose_ of insects, the knowledge of which, as far as it can be obtained, is of essential use to the industrious collector. Entomologists have divided the _Lepidoptera_, with a view to this circumstance, into _diurnal_, _crepuscular_, and _nocturnal_; or butterflies (_Papilio_ L.), hawkmoths (_Sphinx_ L.), and moths (_Phalæna_ L.). These terms may be applied to insects in general.

i. _Diurnal_ insects are abundant. _Butterflies_ in particular fly generally at no other time: they accompany the sun in his course, and before he sets disappear. Some other _Lepidoptera_, though not so named, are _day_ insects:--such are the _Zygænidæ_, &c. amongst the hawkmoths; and amongst the moths, _Plusia Gamma_, the _Phytometræ solares_ of Haworth[1549], and some others. Numberless _Coleoptera_ belong to this section. The _Donaciæ_ fly only when the sun is out and the air is warm; they are then extremely agile and difficult to take. Some _Hopliæ_ swarm in the day before noon, and then disappear[1550]: most of the _tetramerous_ beetles also appear to be diurnal. The _Libellulina_ and many other _Neuroptera_ may also be so termed; and the _Hymenoptera_ almost universally, with the sole exception of the _Formicidæ_[1551]. Amongst the _Diptera_, if we leave out the _Tipulariæ_, the rest will be found for the most part to belong to the present section.

ii. _Crepuscular_ insects, strictly speaking, are those that appear only during the twilight, whether in the morning or evening; but the term may be understood, with some latitude, to signify all those insects that are seen only in the morning and evening, though after sunrise and before sunset. Of these, some come forth only in the _morning_, others only in the _evening_, and others both _morning_ and _evening_. My memory only furnishes me with a single instance of an insect whose principal appearance and flight are in the _morning_. _Catocala nupta_ I have often seen flying at this time, about six or seven o'clock, and never at any other: I am not however prepared to assert that it does not appear in the evening or night, but I have then never met with it. In the _evening_ more particularly you hear the hum of the dung-beetle (_Geotrupes_), which Linné thought the prognostic of a following fine day; and of the swarms of _Melolontha vulgaris_ and _Amphimalla solstitialis_. Then also many other _Coleoptera_ are in the air; especially before a thunderstorm, a state of the atmosphere that particularly excites insects[1552]: _Ptinus imperialis_ and _germanus_ I have never taken except under these circumstances. Then the _Ephemeræ_ sport in the air, and lead their mystic dance. The majority of the hawkmoths are then too on the wing, with their long tongues imbibing the nectar of the flowers while they hover over them, both _morning_ and _evening_.

iii. In the _night_ the main body of the _moths_ take their flight, as well as a vast number of _Coleoptera_ and insects of other orders. At this time the _Blattæ_ and crickets leave their hiding-places and run about: but the other _Grylli_ L., though they sing in the night, fly only in the day. Then also the _Carabi_, like beasts of prey, leave their dark retreats,--in this differing from the _Cicindelæ_, which are diurnal,--and prowl about to entrap other unwary insects. Then, likewise, the female glowworm hangs out her lamp of love, and the male, led by it, wings his way to her: and then the water-beetles (_Dytisci_, _Gyrini_, &c.) forsake the waves and become tenants of the air.

Could we with certainty discover the stations in which insects after their excursions take their _repose_, we might capture many that we now search for in vain. Several of these stations were pointed out in a former part of this letter where I detailed their usual _haunts_. I may here add, that numbers of them, when reposing, conceal themselves from their enemies on the under side of the leaves of trees and plants. Moths, especially the _Noctuidæ_, may often be met with in woods, as before observed[1553], on the _north_ side of the trunks of trees. Mr. Marsham related to me, that once a little before sunset, observing over his head a number of insects on the wing moving on in one direction, he caught some of them, and they proved to be _Labia minor_. Struck with the circumstance, he watched them several evenings; and on one, as he was looking about a melon-pit for insects, he saw these little animals alight on the frame, hastily fold up their wings, and entering under the glasses, run down its sides and bury themselves in the loose earth. This he observed repeatedly. The onward flight of these insects was therefore evidently their return from their diurnal cruise to their nocturnal station.--This happened in September.

I am, &c.

FOOTNOTES:

[1458] Linn. _Philos. Botan._ § 334.

[1459] _Linn. Trans._ x. 20--. &c. _Dict. des Scienc. Nat._ xviii.

[1460] _Selborne_ i. 173.

[1461] _Philos. Entomolog._ ix. § 20.

[1462] _Mém. du Mus._ 1815.

[1463] _Hor. Entomolog._ 42--. 518.

[1464] _Essai Elément. de Géograph. Botan._ 62.

[1465] _Wisdom of God_, &c. 2d edit. 9.

[1466] _Hor. Entomolog._ 469. This calculation includes the _Crustacea_.

[1467] It has lately been discovered that the larva of _Drilus flavescens_, a beetle, feeds upon the common snail. (_Bulletin des Scienc. Nat._ 1824. iii. 297; v. 110; vi. 221.) I have found an _Acarus_ on the same animal.

[1468] See above, p. 219--.

[1469] We employ this term, because the more common one, _herbivorous_, does not properly include devourers of timber, fungi, &c.

[1470] If we consider the number of species of _Acari_, _Nirmi_, _Poduræ_, and _Araneidæ_, this proportion will appear moderate.

[1471] _Hor. Entomolog._ 48.

[1472] _Philos. Entomolog._ ix. § 20.

[1473] _Géograph. Génér. des Ins._ 5.

[1474] _Ibid._

[1475] _Ibid._ 7--.

[1476] _Ibid._ 8, 11.

[1477] _Personal Narrat._ E. T. v. 88. He says also that each stream almost has its peculiar species (_Ibid._ 98), and that they sometimes emigrate to stations they had not infested before. _Ibid._ 106--.

[1478] _Hor. Entomolog._ 519.

[1479] Latr. _ubi supr._ 3.

[1480] _Géographie_, &c. 22--.

[1481] _Ibid._ 27.

[1482] _Géographie_, &c. 20--.

[1483] See above, p. 494.

[1484] As this insect is the type of a distinct genus amongst the _Scutelleridæ_, I have distinguished it by the name Fabricius gave the whole tribe.

[1485] M. Latreille (_Géographie_, &c. 8.) seems to regard these varieties as _distinct_; in which case they would be the _representatives_ of the species named in the text: but the variations are mostly so slight, as not to afford any satisfactory distinctive characters.

[1486] _Géogr. Génér. des Ins._ 2.

[1487] When I described the Melville Island insects for Captain Sabine, I received from him no _Culices_; but I afterwards saw in his possession a genuine one from thence.--K.

[1488] _Linn. Trans._ xii. 380--. n. 6, 7.

[1489] _Ibid._ n. 5.

[1490] Dejean in his catalogue gives only 434 species; while Mr. Stephens, _four_ years ago, had 550, and has since increased the number to above 600.

[1491] _Journal of a Tour in Iceland_, 272.

[1492] VOL. I. p. 115--.

[1493] _Entomogr. Russ._ Coleopt. _t._ xiii. _f._ 1.

[1494] Ahren's _Fn. Europ._ i. 1.

[1495] _Hor. Ent._ 47--.

[1496] _Annulosa Javanica_, 36.

[1497] See the Rev. L. Guilding's admirable _History_ of _Xylocopa Teredo_ and _Horia_ (_Cissites_ Latr.) _maculata_, Linn. Trans, xiv. 313--.

[1498] Out of 51 species described by Bilberg, 28 are African, and 19 of these are from the Cape.

[1499] _Géogr. Génér. des Ins._ 18.

[1500] _Hor. Entomolog._ 45.

[1501] Dr. Leach has described 8 British species (_Linn. Trans._ xi. 37.); Dejean has 7 Spanish ones.

[1502] I have a very splendid species of this genus taken by C. C. Elwes Esq. on the Pyrenees, which is undescribed, and falls under none of the count Dejean's Families, having its elytra perfectly smooth, without striæ, punctures, &c. It is of a brilliant golden green. It stands in my cabinet under the name of _C. lævigatus_. K.

[1503] Fischer _Entomogr. Russ._ 90--. _t._ viii. _f._ 13.

[1504] VOL. III. p. 562.

[1505] Major General Hardwicke gave me one of this description from Nepal.

[1506] Latr. _Géograph._ &c. 18--.

[1507] _Linn. Trans._ xiv. _t._ iii. _f._ 4.

[1508] _Hor. Entom._ 147.

[1509] _Linn. Trans._ ubi supr. _f._ 1.

[1510] _Ibid._ xii. _t._ xxi. _f._ 9.

[1511] _Ibid._ _f._ 14.

[1512] To this genus belong _Melolontha aurulenta_. Ibid. 400; and _M. sericea_. Ibid. 463.

[1513] Latr. _Géograph._ 7.

[1514] _Cetonia atropunctata_ and _Brownii_ of _Linn. Trans._ (xii. 464. _t._ xxiii. _f._ 6.) belong to this genus.

[1515] _Linn. Trans._ xii. _t._ xxii. _f._ 2; _t._ xxiii. _f._ 7.

[1516] Latreille, _Géograph._ &c. 10.

[1517] _Linn. Trans._ xiv. 569.

[1518] See above, p. 496.

[1519] Fischer, _Entomogr. Russ._ i. 135.

[1520] From finding it in water, Fabricius considered this insect as a _Hydrophilus_, but it is a true _Cercyon_.

[1521] See above, p. 401.

[1522] _Personal Narrat._ E. T. v. 91--.

[1523] See VOL. I. p. 470--.

[1524] A species of _Gyrinus_ (_G. Viola aquatica_), described by Modeer (_Linn. Syst. Nat._ Ed. Gmel. i. 1612. n. 9.), is said to inhabit _salt_ water.

[1525] _Géograph._ &c. 6.

[1526] _Apis_ *., a. _Mon. Ap. Angl._ ii. 178--.

[1527] _Linn. Trans._ iv. 30--. v. 96--. _t._ iv.

[1528] VOL. I. LETTER VI.

[1529] _Géograph._ &c. 6.

[1530] VOL. II. p. 255.

[1531] These, as well as _Melecta_, are probably a kind of _Cuckow_-bee. _Mon. Ap. Angl._ i. 150.

[1532] _Melitta_ * *. b. _Mon. Ap. Angl._ i. 138--.

[1533] _Mémoires sur le gènre_ Halicte.

[1534] VOL. II. p. 9.

[1535] _Linn. Trans._ ix. 78--. _t._ i. _f._ 20.

[1536] _Ibid._ 55. _t._ i. _f._ 12.

[1537] This insect does not, I believe, eat the petals of the rose, but _laps_ the nectar it produces. I have seen it employed upon wounded trees lapping the sap.

[1538] _Mon. Ap. Angl._ ii. 172. 257.

[1539] See above, p. 491, note^a.

[1540] _Ibid._ p. 219; and VOL. I. p. 267--.

[1541] _Ibid._ p. 256--.

[1542] _Apis_ * *. e. 2. K.

[1543] _Apis_ * *. c. 2. α. K.

[1544] _Butterfly Collector's Vade Mecum_, 66, note^d.

[1545] De Geer ii. 638--. 641--.

[1546] Swamm. _Bibl. Nat._ i. Conf. 114 with 103.

[1547] Reaum. vi. 480--.

[1548] VOL. II. p. 11.

[1549] _Lepidopt. Britann._ 263--.

[1550] _Linn. Trans._ v. 256.

[1551] VOL. II. p. 95--.

[1552] See above, p. 254--.

[1553] VOL. II. p. 217. See above, p. 200.