46 



HANDBOOK OF ANTS, BEES, ETC. 



the forehead below the ocelli, are short and awl-shaped. These 

 insects, which seem to be found mostly in temperate climates, are 

 remarkable for the great delicacy of their structure, and for the 

 extreme shortness of their lives in the perfect state, which seems 

 in general scarcely to exceed a day. 



Nearly fifty species of Ephemeridce occur in this country. The 

 best known is Ephonera vu/gata, of which the sub-imago is 

 called the " green drake," and the imago the " grey drake " by 

 anglers. The two-winged Cloe7t diptera, which, however, is a 

 much smaller species than the foregoing, is also very abundant. 



Fig. 56. — Calopteryx Virgo (Female-) 



Tribe III. — Plecoptera. 



The Plecoptera contain only one family. 



Family 4, Perlidce. — The Perlidce^ or Stone Flies, are chiefly 

 inhabitants of the temperate regions ; they are of small size, and 

 not very numerous in species, about thirty being indigenous to 

 the British Isles. 



The larvcB, which are aquatic in their habits, closely resemble 

 the perfect insect in form. Their food consists of other insects 

 and they prey especially upon the laj'vce of the Day Flies. 



The perfect insects are usually found resting quietly on plants 

 and other objects on the banks of streams. The large brown 

 species, Pe7'la bicaudafa, appears in the spring, and is very 

 common in the neighbourhood of pools, streams, and canals. 



