NEUROPTERA. — EPHEMERID&. 29 
fect state is sometimes so immense, that the swarms of one species 
with white wings (E. albipennis) has been compared to a fall of snow; 
whilst, in some parts of Europe where they abound, it is the custom 
to collect their dead bodies into heaps, and use them for manure. 
The fishes at such time eagerly wait for them; and so great are the 
numbers which fall inte the water, that the fishermen call them 
manna.* They are well known to the angler as excellent baits for 
trout. They are also a favourite food of the smaller dragon flies. 
If, however, the life of these insects in their perfect state is so short, 
it is of much greater duration in the preparatory states, extending 
at least, in some species, to two or three years. During this pe- 
riod, they are inhabitants of the water, in which they ordinarily hide 
themselves, during the day, in the earth, under stones, or in horizontal 
burrows, divided internally into two canals, each having a separate 
opening externally, and uniting internally at the extremity, so that 
the insect can crawl in at one hole and out of the other, without 
being obliged to make the awkward turn it would have to do, if 
in a straight hole: these burrows are formed in the earth of the 
sides of the stream, or standing water, and which circulates freely in 
them. It is affirmed by some authors, that the larva feeds upon 
the mud at the sides of its retreat (Hist. of Insects, p. 106.).. Swammer- 
dam, who dissected these larve, always found mud within the stomach 
and the great and small intestines. It is most probable, therefore, 
that when the larva has assimilated the decaying vegetable matter 
therein contained, the earthy particles are discharged. The larvae bear 
a considerable resemblance to the imago in their general form, but 
are easily distinguished by their long multiarticulate antenne ; the 
want of ocelli; the presence, in some species, of two corneous ap- 
pendages in front of the head, considered as mandibles, and more 
* T must refer to Kirby and Spence’s Introduction for yarious particulars relative 
to the almost incredible appearance of the swarms of these insects upon certain 
occasions, 
+ Out of forty-four species of insects given by Mr. Ronald in his Fly Fisher’s Ento- 
mology, eighteen belong tothe present family. Amongst the smaller species, the pseud- 
imago and imago are known under different names. The various kinds of duns are all in 
the pseudimago state, the name evidently applying to their duller colour. The green 
drake is the pseudimago, and the grey drake the imago of E. vulgata?. See further 
Sir H. Davy’s Salmonia, and the late editions of Zsaac Walton. The females, filled 
with eggs, are most eagerly seized by the fish ; the males, inflated with air, offer them 
but little nourishment, and are called bastard May flies by the Oxfordshire fish- 
ermen. It is rarely that the females are found in the swarms hovering on the 
water. 
