486 



HISTORY OF INSECTS. 



kinds are produced from the egg in the form 

 of worms ; from whence they change into a 

 more perfecj; form ; namely, that of aurelias, 

 which is a kind of middle state between a 

 worm and a fly ; and from thence they take 

 their last mutation, which is into a beautiful 

 fly, of longer or shorter duration, according to 

 its kind. 



The ephemera, in its fly state, is a very 

 beautiful-winged insect, and has a strong si- 

 militude to the butterfly, both from its shape 

 and its wings. It is "about the size of a mid- 

 dling butterfly ; but its wings differ in not 

 being covered with the painted dust with which 

 those of butterflies are adorned, and rendered 

 opaque, for they are very transparent, and very 

 thin. These insects have four wings, the up- 

 permost of which are much the largest ; when 

 the insect is at rest, it generally lays its wings 

 one over the other, on the back. The body 

 is long, being formed of six rings, that are 

 larger at the origin than near the extremity ; 

 and from this a tail proceeds, that is longer 

 than all the rest of the fly, and consists some- 

 times of three threads of an equal length, or 

 sometimes of two long and one short. To ac- 

 quire this beautiful form, the insect has been 

 obliged to undergo several transmutations: but 

 its glory is very short-lived, for the hour of its 

 perfection is the hour of its death ; and it seems 

 scarcely introduced fo pleasure, when it is 

 obliged to part with life. 



The reptile that is to become a fly, and that 

 is granted so long a term, when compared to 

 its latter duration, is an inhabitant of the wa- 

 ter, and bears a very strong resemblance to 

 fishes, in many particulars ; having gills by 

 which it breathes at the bottom, and also the 

 tapering form of aquatic animals. These in- 

 sects have six scaly legs, fixed on their corse- 

 let. Their head is triangular: the eyes are 

 placed forward, and may be distinguished by 

 their largeness and colour. The mouth is fur- 

 nished with teeth ; and the body consists of 

 six rings ; that next the corselet being largest, 

 but growing less and less to the end : the last 

 ring is the shortest, from which the three 

 threads proceed, which are as long as the 

 whole body. Thus we see that the reptile 

 bears a very strong resemblance to the fly ; 

 and only requires wings to be very near its 

 perfection. 



As there are several kinds of this animal, 

 their aurelias are consequently of different col- 

 ours ; some yellow, some brown, and some 

 cream-coloured. Some of these also bore 

 themselves cells at the bottom of the water, 

 from which they never stir out, but feed upon 

 the mud composing the walls of their habita- 

 tion, in contented captivity ; others, on the 

 contrary, range about, go from the bottom to 

 the surface, swim between two waters, quit 



that element entirely to feed upon plants by 

 the river side, and then return to their favour- 

 ite element for safety and protection. 



The reptile, however, though it lives two or 

 three years, offers but little, in its long dura- 

 tion, to excite curiosity : it is hid at the bot- 

 tom of the water, and feeds almost wholly 

 within its narrow habitation. The most strik- 

 ing facts command our attention during the 

 short interval of its fly state ; into which it 

 crowds the most various transactions of its 

 little life. It then may be said to be in a 

 hurry to live, as it has but so small a time to 

 exist. The peculiar sign whereby to know 

 that these reptiles will change into flies in a 

 short time, consists in a protuberance of the 

 wings on the back. About that time the 

 smooth and depressed form of the upper part 

 of the body is changed into a more swollen 

 and rounder shape ; so that the wings are, in 

 some degree, visible through the external 

 sheath that covers them. As they are not na- 

 tives of England, he who would see them in 

 their greatest abundance must walk, about 

 sun-set, along the banks of the Rhine, or the 

 Seine near Paris ; where, for about three days, 

 in the midst of summer, he wiil be astonished 

 at their numbers and assiduity. The thick, 

 est descent of the flakes of snow in winter 

 seems not to equal their number: the whole 

 air seems alive with the new-born race ; and 

 the earth itself is all over covered with their 

 remains. The aurelias, or reptile insects, that 

 are, as yet, beneath the surface of the water, 

 wait only for the approach of evening to be- 

 gin their transformation. The most industri- 

 ous shake off their old garments about eight 

 o'clock ; and those who are the most tardy, are 

 transformed before nine. 



We have already seen that the operation of 

 change in other insects is laborious and pain- 

 ful ; but with these nothing seems shorter, or 

 performed with greater ease. The aurelias 

 are scarcely lifted above the surface of the 

 water, than their old sheathing-skin bursts; 

 and through the cavity which is thus formed, 

 a fly issues, whose wings, at the same instant, 

 are unfolded, and, at the same time, lift it into 

 the air. Millions and millions of aurelias rise 

 in this manner to the surface ; and at once be- 

 come flies, and fill every quarter with their 

 flutterings. Rut all these sports are shortly lo 

 have an end ; for, as the little strangers live 

 but an hour or two, the whole swarrn soon falls 

 to the ground, and covers the earth, like a 

 deep snow, for several hundred yards, on every 

 side of the river. Their numbers are then in- 

 credible, and every object they touch becomes 

 fatal to them ; for they instantly die if they 

 hit even against each other. 



At this time the males and females are very 

 differently employed. The males, quite in- 



