EEUROPTERA. 
57 
insect, no longer a dirty, sluggish, grovelling, creeping 
thing, but an active and beautiful denizen of the air. 
The Perlidce , or Stone-flies of the Fly-fisher, is a 
family of small extent; there are only a few species of 
moderate size, and are distinguished by the posterior wings 
being much larger than the anterior. These insects are 
all aquatic ; the eggs are deposited in the water; the 
larvae are very like the perfect insect; they are to be found 
in great quantities under stones in rivers and ponds ; 
they are sluggish in their movements, adhering closely 
to the sides of stones. One of the largest of the 
family is the Stone-fly of the angler, the Perla bicau - 
data (Fig. 6) it appears in April; another species 
known to fishermen in some parts as the “ Yellow Sally,” 
the Chloroperla viridis, makes its appearance in May. 
Respiration in the larvae is carried on by means of 
gills attached sometimes to the thorax, sometimes to the 
abdomen. None of the British Perlidae are distinguished 
for much beauty of colour, but some exotic kinds are 
richly tinted, such, for instance, as the Eustlienia Spec - 
tails of Westwood, an Australian species, with pink 
and violet-tinted wings, of which insect M. Pictet’s 
figure is before me as I write. 
The Ephemeridce or May-flies, so well known to the 
Fly-fisher, are distinguished by the small size of their 
hinder wings and their antennae, by the absence of a 
true mouth—for the organs are in a very rudimentary 
condition—and by two or three long hair-like* ap¬ 
pendages at the end of the tail. The family consists of 
several genera; the best known species being the 
Ephemera vulgata, the yellow and grey drake of the 
angler. Some of the small kinds belonging to the 
