HEMIPTEKA. 515 



of the body, while the side pieces (the epimera and episterna) 

 are large and of much the same form as in the Coleoptera, and 

 the legs are situated close together, with coxae and trochanters 

 very similar to those of the Coleoptera. The body is usually 

 very flat above, or, in the more or less cylindrical species, 

 somewhat broad and flat. The body is less concentrated 

 headwards than in the Coleoptera, though much more so than 

 in the Orthoptera, and in this respect, as well as in other 

 essential characters, the group is intermediate between these 

 two suborders. Both pairs of wings are very equal in size 

 and alike in shape, except in the higher families where they 

 are very unequal, the hinder pair being very small. They are 

 generally very regularly ovate in shape, the costal edge being 

 much curved and rounded towards the obtusely rounded apex ; 

 the outer edge is long and very oblique, and the inner edge 

 short, though often longer than the outer edge in the lower 

 families. The type of venation is rather peculiar in this sub- 

 order, as the costal veins are large and stout, while, as seen in 

 the wings of Aphis, the median veins are sent out from the 

 costa ; indeed there is no central powerful vein in the middle 

 of the wing ; in other words the wing is scarcely differentiated 

 into its three special regions, so well seen in the Hymenoptera 

 and Lepidoptera, and especially the Orthoptera. The surface 

 is net-veined rather than parallel-veined, but there are few 

 veinlets, and the interspaces are large and few in number, 

 and in this respect most Hemiptera show their superiority 

 to the Orthoptera and Neuroptera. In the lower section of 

 the suborder, the Heteropterous Hemiptera, the thickening of 

 the basal half of the wing tends to obliterate all traces of the 

 veins, and especially the veinlets. 



The legs are slender, and often very long, owing to the great 

 length of the femora and tibiae, while the tarsi, like those of 

 the lowest Coleoptera, are two or three-jointed. 



The abdomen has six to nine segments apparent, though 

 the typical number is eleven, according to Lacaze-Duthiers. 

 The stigmata are very distinct, being often raised on a tubercle. 

 On the basal ring of the abdomen are two cavities in which 

 are sometimes seated vocal organs, as in the male Cicada, and 

 in the metathorax of some species are glands for secreting a 



