EPHEMERIDA. 
8 7 
Family EPHEMERlDiE (Eph-e-mer'i-dae). 
The May-flics. 
In river or lake towns, during the warm evenings of late 
spring or early summer, the electric lights or street lamps are 
often darkened by myriads of insects that dash against them, 
and the pavements are made slippery by their dead bodies 
which have been trampled under foot. They are not the ordi¬ 
nary night-flying moths: if an individual of the thousands 
that cling to the posts and buildings in the vicinity of the 
light be examined, it will prove to be a delicate creature with 
dainty, trembling wings and two or three long, 
white, thread-like organs on the end of its body ; 
the body itself is so transparent that the blood 
within can be seen pulsating. The front 
wings are large and finely netted, and the 
hind wings are small or absent (Figs. 94, 95). Fl a‘ two^ngeS 
So fragile are these pale beings that they seem 
like phantoms rather than real insects. No wonder that 
poets have sung of them as the creatures that live only a 
day. It is true that their winged existence lasts often 
only a day or even a few hours; but they have another 
life, of which the poet knows nothing. Down on the 
bottom of a stream, feeding on mud, water-plants, or other 
small insects, lives a little nympli with delicate, fringed 
gills along its sides and two or three long, many-jointed, 
and often feathery appendages on the end of the body (Fig. 
96). It has strong legs and can both walk and 
swim. After about the ninth molt there may be 
twenty molts in all—there appear on its thorax 
four little sacs which are the beginnings of wings; 
with each molt these grow larger, until finally the 
last skin of the water-nymph is shed, and gills and 
mouth-parts are all left behind, and the insect 
comes forth, a winged May-fly. But there is still 
o?May-Xy. P another change to be undergone. The insect 
has not yet reached the adult state. After flying a 
