THE CLASSIFICATION OF INSECTS 71 



species, their distribution being world - wide. Many 

 families are recognised. Most of the species subsist upon 

 the juices of plants ; but some prey upon smaller insects, 

 while a few suck the blood of birds and mammals. 

 Many species pass the whole of their lives in water. 



Sub-Order 2. — Ilomoptera. 



In this sub-order the fore-wings are sometimes firmer 

 than the hind-wings, but there is never a hard basal area. 

 Commonly, the wings of both pairs are uniformly mem- 

 branous, the hind-wings being relatively small ; but 

 there are many wingless species. The life-histories of 

 these insects indicate they are on a higher plane than 

 their congeners the Heteroptera. The newly-hatched 

 young often differ from their parents in a marked degree, 

 and may be regarded as true larva?; while among scale 

 insects there is a passive pupa-like stage before the last 

 moult. All Homopterous insects suck the juices of 

 plants. 



The cicadas (Cicadidce) have large wings of uniform 

 texture. The males possess two drum-like membranes on 

 the underside of the thorax, the vibration of which gives 

 rise to a shrill sound, known as the "song of the cicada." 

 The nymphs burrow in the ground, and suck the roots of 

 plants. Cicadas abound in the tropics of both hemi- 

 spheres, but are far less numerous in temperate regions. 

 One small species is occasionally found in Britain. 



The lantern-flies (Fulgoridce) get their popular name 

 from curious processes which project from the heads of 

 certain species. These were formerly believed to be 

 luminous ; but this is not the case. The antennas are 

 placed beneath the eyes. The fore-wings are firmer in 

 texture than the hind-wings; while in many species all 



