HEMIPTERA. 159 



than the wings, semi-membranous, like the elytra of the Orthoptera, 

 and sometimes opaque and coloured, sometimes transparent and 

 veined. There are a few longitudinal plicae in the wings. 



The composition of the trunk begins to experience modifications 

 which approximate it to that of the Insects of the following orders. Its 

 first segment, hitherto designated by the name of thorax, has, in se- 

 veral, much less extent, and is incorporated with the second, which is 

 equally exposed. 



Several have simple eyes, of which, however, there are frequently 

 but two. 



The Hemiptera exhibit the same forms and habits in their three 

 states. The only change they experience consists in the development 

 and growth of the volume of the body. They usually have a stomach 

 with firm and muscular parietes, a small intestine, followed by a large 

 one divided into several inflations, and biliary vessels, few in number, 

 and inserted at a distance from the pylorus. I divide this order into 

 two sections *. 



In the first, that of the Heteroptera, Lat., the rostrum arises 

 from the front; the elytra are membranous at the extremity, and the 

 first segment of the trunk, much larger than the others, alone forms 

 the thorax. 



The elytra and wings are always horizontal or slightly inclined. 



This section is composed of two families. 



FAMILY I. 



GEOCORISiE. 



In this family the antennae are exposed, longer than the head, and 

 inserted between the eyes, near their internal margin. There are 

 three joints in the tarsi, the first of which is sometimes very short. 



It forms the genus 



CiMEX, Lin. 



In some, or the Longilabra, the sheath of the sucker consists of four 

 exposed and distinct joints, the labrum is much prolonged beyond the 

 head, subulate, and striated superiorly. 



The tarsi always consist of three distinct joints, the first of which 

 is almost as Icng as the second, or longer. These species always dif- 

 fuse a disagreeable odour, and suck the juices of various Insects. 



Sometimes their antennae, always filiform, are composed of five 

 joints; the body is generally short, oval, or rounded. 



* In the systems of Messrs. Kirby and Leacli, they form two orders. Our 

 Heteroptera are there termed Hemiptera, and our section of the Homoptera forms the 

 eecond uuder the same name. 



