THE EPHEMERA. 



487 



aciive, and apparently without desires, seem 

 only born to die : no way like the males of 

 other insects, they neither follow the opposite 

 sex, nor bear any enmity to each other : after 

 fluttering for an hour or two, they drop upon 

 iand, without seeming to receive wings for 

 scarce any other purpose but to satisfy an idle 

 curiosity. It is otherwise with the females ; 

 they are scarce risen from the surface of the 

 water, and have dried their wings, but they 

 hasten to drop their eggs back again. If they 

 happen also to flutter upon land, they deposit 

 their burden in the place where they drop. 

 But then it may be demanded, where, and in 

 what manner, are these eggs fecundated, as no 

 copulation whatever appears between the sexes 

 in their transitory visits in air? Swammer- 

 dam is of opinion, that they are impregnated 

 in the manner of fish-spawn, by the male, after 

 being ejected by the female ; but beside that 

 this doctrine is exploded even from the history 

 of fishes, it is certain that the males have not 

 time for this operation, as the eggs drop to the 

 bottom the instant they are laid on the water. 

 Reaumur is of opinion that they copulate ; but 

 that the act bears a proportion in shortness to 

 the small duration of their lives ; and, conse- 

 quently, must be so soon performed as to be 

 scarcely visible. This, however, is at best for- 

 cing a theory ; and it is probable, that as there 

 are many insects known to breed without any 

 impregnation from the male, as we have al- 

 ready seen in muscles and oysters, and shall 

 hereafter see in the gnat, and a species of the 

 beetle, so the ephemera may be of this num- 

 ber. Be this as it may, the females are in 

 such haste to deposit their eggs, that multi- 

 tudes of them fall to the ground ; but the 

 greatest part are laid in the water. As they 

 flutter upon the surface, two clusters are seen 

 issuing from the extremity of their body, each 

 containing about three hundred and fifty eggs, 

 which make seven hundred in all. Thus, of 

 all insects, this appears to be the most prolific; 

 and it would seem that there was a necessity 

 for such a supply, as, in its reptile state, it is 

 the favourite food of every kind of fresh-water 

 fish. It is in vain that these little animals 

 form galleries at the bottom of the river, from 

 whence they seldom remove ; many kinds of 

 fish break in upon their retreats, and thin their 

 numbers. For this reason fishermen are care- 

 ful to provide themselves with these insects, as 

 the most grateful bait ; and thus turn the fish's 

 rapacity to its own destruction. 



But though the usual date of those flies is 

 two or three hours at farthest, there are some 

 kinds that live several days ; and one kind in 

 particular, after quitting the water, has ano- 

 ther case or skin to get rid of. These are of- 

 ten seen in the fields and woods distant from 

 the water; but they are more frequently found 



in its vicinity. They are often found sticking 

 upon walls and trees ; and frequently with the 

 head downwards, without changing place, or 

 having any sensible motion. They are then 

 waiting for the moment when they shall be di- 

 vested of their last incommodious garment, 

 which sometimes does not happen for two or 

 three days together. 1 



1 House-fly. Of all insects, perhaps the most widely 

 distributed and abundant in number of individuals, is the 

 house fly, Musca Domestica, a species which from its 

 constant occurrence in every situation, will render any 

 precise description of it unnecessary ; and yet, many 

 of our readers are, perhaps, unaware that, of the flies 

 which crawl up our windows, there are not only several 

 distinct species, but also that the insect at whose torment- 

 ing attacks upon our legs in the showery days of summer, 

 we are so often enraged, does not even belong, notwith- 

 standing its apparent identity, to the same genus. If one 

 of these annoying tormentors (which is the Stomoxys 

 calcitrans) be caught and examined, it will be found that 

 the mouth is formed into a horny sharp-pointed weapon, 

 capable of piercing the flesh, whilst the soft blunt ap- 

 paratus of the mouth of the musca is quite incompetent 

 to such an operation, being fitted only for the sipping of 

 fluids, or the extraction of honied sweets ; forming in 

 fact, a long tubular sucker, jointed in the middle so as 



B A 



Head of the Jly, with the mouth extended; A. seen sideways, 

 B. seen from above. 



to fold back close to the head (Fig. A. and B.), and armed 

 at the base with a pair of exarticulate feelers and at the 

 extremity with two fleshy lobes, which are employed as 

 instruments of suction. This organ possesses very great 

 muscular power, and we have seen the insect by its 

 assistance alone carry off pieces of sugar much larger than 

 its head. The under surface of the terminal lobes is also 

 transversely ridged, which must necessarily give greater 

 facility to the actions of the organs, by enabling it to 

 adapt itself more readily to rough surfaces (Fig. c.). It 

 is essential, however, that the mouth should be provided 



Extremity of the sucker of the fly, sJiowing its annulated 

 appearance. 



with some instrument for piercing even the soft substances 

 of which the food is composed, and we accordingly find 

 a fine point (the tongue) arising near the elbowed part of 

 the proboscis, which is for safety lodged in a stronger 

 point (the labrum), both when at rest fitting into the canal 

 of the proboscis, as represented in our figure B. 



