Insects] 



MUSEUM OF ANIMATED NATURE. 



367 



bark of Ihe young branch, its first procedure being 

 to lay down a somewhat triangular platlbrm, the 

 sides of which extend beyond the twig, and slope 

 obliquely upwards. This beincr finished, the next 

 thing is to draw the edges of the sides of the plat- 

 form together, which it does in the same way as 

 many of the leaf-rollers draw the sides of a leaf 

 together, namely, by means of silken cords which 

 they strain till the two edges meet. An opening 

 at the upper part is still left ; but this is after- 

 wards closed in a similar manner. When finished, 

 the whole looks like a tumour or excrescence on the 

 bark. Fig. 3587 represents — a, the platform of this 

 structure, magnified, before the walls are closed ; 

 b, the walls closed, excepting at the upper part ; 

 ..c, a side view of the structure complete. The 

 caterpillars of many insects construct cells of earth 

 ■underground, in which they lie torpid in pupa state 

 ' .tduring the winter, the perfect insect appearing in 

 the spring. They make these cells of. pellets of 

 •earth, which they moisten and work into a proper 

 ■consistence, and bind to each other with very fine 

 silken tissue. They work, in completing their cell, 

 iham the inside, which they render veiy smooth 

 and even, generally lining it with silken arras; tliis 

 they complete when the aperture is finally closed. 

 JSuch cells are made by ihe caterpillars of the ghost- 

 moth (HepiaiusHumuli), of the water-betony moth 

 .{Cucuilia Scrophularife), and many others. 



Fig. 3i5S8 shows the rough outside of these cells 

 of earth. Fig. 358D shows — A, the exterior of the 

 cell ; B, a section disclosing the pupa in a smooth 

 ■silk-lined chamber; C, the caterpillar; D, the 

 moth. Fig. 3590 shows other nests of earth, with 

 Ihe caterpillar at work, and a section of one, so as 

 to display the smooth inside. The caterpillar and 

 •moth are also represented. 



There are several small moths of the genus Tinea, 

 termed clothes-moths, fur-moths, cabinet-moths, 

 &c., the caterpillars of which feed on various ani- 

 mal substances, as fur, silk, woollen stuffs, and the 

 like. Some are the plague of museums, despoiling 

 sare skins and the plumage of birds ; nay, the very 

 cabinets of insects are subject to their visitations, 

 and often the mischief is not discovered till too 

 late. The moth lays her eggs on the fur, cloth, or 

 •other material on which the future caterpillars are 

 to feed, and these on exclusion prepare for them- 

 selves a soft investment or cloak, and folded in this 

 Ihey commence their ravages. In order to prepare 

 their tent, they cut hairs, or filaments of wool, or 

 portions of feathers, and bind them together with 

 threads of silk, continuing till a felt-like fabric is 

 made of sufficient size to wrap round the body ; this 

 they fold around them, bringmg the edges together 

 and securing them with silk. As it grows they both 

 add to the length of this case and to its diamet.er ; 

 in the former instance they work in fresh materials at 

 each end, and if shifted to stuffs of various colours, 

 the tissue will be parti-coloured. In the second 

 instance the caterpillar slits the case, first at one 

 end and then at the other, and works in a strip of 

 ♦he requisite breadth. Fig. 35D1 shows the cases of 

 the clothes-molh (Tinea pellionella) : a, caterpillar 

 feeding in a case which has been lengthened by 

 ovals of different colours ; b, a case cut at the ends 

 for experiment ; c, a case partially slit by the cater- 

 pillar in order to enlarge its circumference ; d and 

 ■e, tlie clothes-moths in (heir perfect state. There 

 are other caterpillars belonging to this family of 

 moths, which feed upon leaves and vegetable ali- 

 ment ; and these make for themselves a case, which 

 they cari-y about with them, as a snail does its shell, 

 changing them when necessary. This case is com- 

 posed of a portion of leaf, not indeed of the whole 

 substance, but of the upper layer or membrane, 

 artfully separated from the lower, and rolled up into 

 the proper form. In order to effect this, it eats 

 through one of the two membranes and gnaws into 

 the parenchyma or pulp between them, which it 

 devours, thus rendering the two membranes, which 

 are very thin, perfectly transparent. Having 

 fashioned a piece of tlie proper shape and size, it 

 joins the edges, and ultimately disengages the case, 

 and travels along the leaf, with its head and limbs 

 only emerging from its portable domicile. We 

 have seen these abundantly on the leaves of the 

 gooseberry-bush and currant ; others are found on 

 the elm, hawthorn, oak, and various fruit-trees. 

 The cases appear erect or nearly so when the cater- 

 pillar is not moving or feeding, and the edge of the 

 orifice appears to be glued to the leaf. 



Fig. 35s)2 shows one of these cases on a leaf of 

 ithe elm — « «, the part of Ihe leaf from which the 

 «ase has been cut out ; b, the case itself. 



Fig. 3593 shows the process in which this tent is 

 formed — a, the caterpillar occupying the space it 

 has eaten between the upper and under cuticle of 

 the leaf; b, a portion of the upper cuticle cut out 

 for the formation of the case; c, the case nearly 

 compute; d, the pertectly closed case, with the 

 cateipillar protruding its head. 

 A still more curious dwelling is made by the 



minute caterpillars of a small moth. Tinea, which 

 feed on the lichens growing on old walls. The 

 dwelling or case is conical, slightly curved, freely 

 open at the base, and with a small orifice at the 

 apex. It is composed of minute particles of stone, 

 which the caterpillar detaches grain by grain, add- 

 ing them to the wall of its structure and securing 

 them by silk. To complete one of these houses (in 

 which the caterpillar travels about, without quitting) 

 requires the labour of twenty-four hours. Generally 

 minute portions of green lichen are mingled with 

 the other particles; and the whole structure is 

 beautifully neat. When about to become a pupa 

 the caterpillar becomes stationary and secures its 

 case to the stone by a strong network of silk, and 

 also closes the larger opening with a curtain of the 

 same material ; it enlarges the small orifice, to permit 

 its exit when a perfect moth, but takes care to 

 spin over it a temporary canopy of silk, which it 

 can burst through without difficulty. 



Fig. 3594 represents these conical cases, both of 

 the natural size and enlarged. 



There is a small caterpillar which feeds upon the 

 willow and inhabits a case or dwelling which it 

 carries about with it as its home. It is well known 

 that the catkins of the willow become, as they 

 ripen, covered with fine down; one of these cat- 

 kins, wonderful to relate, is selected by the cater- 

 pillar, which burrows into it, rendering it tubular, 

 and lining the interior with silk ; this done, she de- 

 taches it from the slender twig on which it was 

 growing, and proceeds to feed, protruding the head 

 for that purpose, but withdrawing it on the appear- 

 ance of danger. If blown into the water, which 

 often happens, as the willow is generally near 

 streams and ponds, the catkin tenement floats 

 lightly, with every chance of being driven to the 

 bank, the caterpillar thus having an opportunity 

 of regaining the same or an adjacent tree. Fig. 

 3595 represents a branch of the willow with downy 

 catkins: b, catkins appropriated by caterpillars; 

 c, the caterpillar. 



Many caterpillars are leaf-miners, winding a tor- 

 tuous course between the upper and under cuticle, 

 and feeding on the parenchyma, or intervening 

 structure ; and fro.m the transparency of the former, 

 leaving their track clearly visible. The caterpillars 

 of some of the small weevils (Curculionidae) are j 

 leaf-miners, as are those also of a few dipterous 

 flies, but most are the larvae of minute moths 

 (CEcophora), which beneath a lens show the most 

 dazzling brilliancy and iridescence. 



The insect deposits an egg on the surface of a 

 leaf, the caterpillar when excluded immediately 

 bores its way in, and begins to tunnel, and as it in- 

 creases in size the mine is of course enlarged, yet 

 without the cuticle being injured. Sometimes it is 

 only on the upper surface of the leaf that the track 

 of the caterpillar is clearly perceptible, showing 

 that, delicate as a leaf may be, the insect has only 

 devoured the upper half of the intervening paren- 

 chyma. Fig. 359G shows the leaves of the monthly 

 rose-tree mined by the caterpillar of the golden 

 silver-spot moth (Argyromiges Rayella). In the 

 centre of the tortuous course made by this caterpillar 

 a dark line may be observed ; it is formed by the 

 liquid rejectamenta of the insect. In this instance 

 the track is to be seen only on the upper surface. 

 Fig. 3597 represents the leaves of the common 

 bramble (Rubus fruticosus) in which the winding 

 track of a mining caterpillar is visible on both sides. 

 Fig. 3598 shows a leaf of the primrose (Primula 

 veris) mined by the caterpillar of a small brilliant 

 moth (fficophora). 



In some instances the mining caterpillar feeds on 

 different plants, and even on exotics, as well as in- 

 digenous. The larva of a small dipterous fly 

 (Tephritis Serratulse) has been known, for example, 

 to mine the leaves of the Cineraria cruenta and the 

 American groundsel (^Senecio elegans), both ex- 

 otics ; it is common on the sow-thistle (Sonchus 

 oleraceus). Fig. 3599 represents— a, the Tephritis 

 Serratulae ; b, the mined leaf of a sow-thistle ; e, the 

 mined leaf of Senecio elegans ; d, the mined leaf of 

 Cineraria cruenta. 



Let us now advert to insects the larvae of which 

 are aquatic, some being organized for respiring the 

 surrounding fluid, others having an apparatus for 

 breathing atmospheric air. 



We may first notice the Ephemera, or May-fly, of 

 which there are several species ; the larva) are aqua- 

 tic, living two or three years in the water, generally 

 of streams and rivers, where they conceal themselves 

 in holes which they excsivate under the bank or 

 beneath stones or pieces of timber. 



The spiracles of these larvae are at the base of a 

 series of fin-like fringed appendages or gills ex- 

 tending down each side of the body, and into these 

 the tubes convey the water, which undergoes de- 

 composition, or at least has the air separated from 

 it and transferred to the tracheas. These fins are in 

 continual and rapid agitation, but by what process 

 the separation of the air becomes effected is not 



very clear. Besides these lateral appendaiies the 

 larvae have three pairs of limbs which enable them 

 to crawl about. The pupa diflers but little from Ihe 

 larva, except in having a case on the thorax enclosing 

 the future wings, and when about to undergo its 

 last change it seeks some dry place, a stor.i •ising 

 out of the water, or a plant, and the skin bursting 

 at the head and thorax the ephemera emerges ; the 

 wings soon expand and the msect takes to flight, 

 strange to say, however, it has to undergo another 

 process, in which respect the ephemera is without a 

 parallel as far as known among insects. After 

 being released from the skin of the pupa, and 

 flying to a considerable distance, the ephemera 

 settles, and withdraws its body, limbs, and even 

 wings from a thin pellicle which has enclosed them, 

 as a glove encloses the hand. So slinht is the 

 opening through which the insect withdraws itself, 

 and so exactly does the exuvium jesemble the 

 insect (for it remains statu quo attached to the spot 

 where the ephemera disrobed itself), that it may be 

 mistaken for the living being. 



Theephemeric attain to maturity and pair; the 

 females lay their eggs, and in a few hours the 

 winged multitude has perished. Some species are 

 disclosed after sunset, lay their eggs and die before 

 sunrise ; some live but about three or four hours. 



Fig. 3600 shows the perforations of the larvae of 

 the ephemera: A, the larva; B, perforations in a 

 river bank : C, one of the perforations laid open to 

 show the parallel direction. 



Fig. 3G0I represents a submerged portion of a 

 willow-tree, which had been previously bored by 

 the caterpillar of Cossus ligniperda ; of the holes, 

 filled with moist clay, the larvte of the ephemera 

 had availed themselves, and there taken up their 

 quarters. 



Fig. 3602 is a dissection of the larva of the May- 

 fly: a a a, spiracles; b b b, lateral trachea;. The 

 central nervous chain with its ganglia is well repre- 

 sented. The fin-like appendages of one side are 

 removed. 



Ephemerae sometimes appear in astonishing mul- 

 titudes filling the air for miles. We have ourselves 

 seen them "thick as autumnal leaves in Valom- 

 brosa," on the banks of the Wye in Derbyshire ; they 

 covered the stones jutting out of the stream, the 

 gates, and the stumps of trees, and nmltitudes 

 drifted into the water and became the prey of the 

 trout and the grayling. 



A scene of this kind was witnessed by Rdaumur 

 on the banks ot the Marne : — " The myriads of 

 ephemerae which filled the air over the current of 

 the river, and over the bank on which I stood, are 

 neither to be expressed nor conceived. When the 

 snow falls with the largest flakes and with the least 

 interval between them, the air is not so filled as it 

 was around me with ephemerae : scarcely had I re- 

 mained in one place a few minutes when the step 

 on which I stood was quite concealed with a layer 

 of them from two to four inches in depth. Near the 

 lowest step a surface of water of five or six feet di- 

 mensions every way was entirely and thickly covered 

 by them, and what the current carried off was con- 

 tinually replaced. Many times I was obliged to 

 abandon my station, not being able to bear the 

 shower of ephemerae which, falling obliquely, struck 

 every part of my face, filling my eyes, mouth, and 

 nostrils." 



The fishermen of the Marne and Seine, to whom 

 these insect-showers are welcome, say respecting 

 them when they commence, — "the manna begins 

 to fall," or "the manna is abundant." 



The larvae of the Phryganeae, a group allied to 

 the Ephemerae, and also often called May-flies, live 

 in the water, and make for themselves curious 

 habitations, which, snail-like, they drag about with 

 them as they crawl along the sandy bottom of riveis 

 and streams. The fisherman knows them by the 

 name of Caddis-worms, as he knows those of the 

 ephemera by the name of Bank-bait. 



These Caddis-worms, the larviB of different species 

 of Phryganea, construct their tenements respectively 

 of various materials : some glue bits of slick toge- 

 ther, and thus make a rough case ; some use portions 

 of reed ; some fragments of rushes, and form a fluted ' 

 cylinder; some roll portionsof leaves spirally around 

 them, some avail themselves of fine particles of 

 sand, and form a very neat and compact cylinder; 

 others agglutinate together small river-shells, mi- 

 nute pebbles, bits of stick, and other materials, 

 making a rough domicile, hned, however, with soft 

 silk. 



Fig. 3603, the rounded case of a caddis-worm, 

 made of the leaves and bits of stems of aquatic 

 plants, and secured to a reed. Fig. 3604, the case, 

 made of portions of reed joined together. 



In clear water these larvae may be observed, with 

 their head and legs protruded, crawling about ia 

 quest of food, and dragging their case after them. 

 We have seen numbers surround a crushed snail, 

 purposely thrown in, and commence devouring it. 

 Many of the larvae of the Phryganeae are very 



