428 INSECTA. 



little distance from their origin, so that in reality the sucker is com- 

 posed of four pieces. 



The mouth of Hemipterous Insects is only adapted for extracting 

 fluids by suction; the attenuated stylets of which the sucker is form- 

 ed, pierce the vessels of plants and animals, and the nutritious fluid, 

 being successively compressed, is forced into the internal canal, and 

 thus arrives at the oesophagus. The sheath of this apparatus is at 

 these times frequently bent into an angle, or becomes geniculate. 

 These Insects, like other Suctoria, are furnished with salivary 

 vessels. 



In most of the Insects which compose this order, the elytra are 

 coriaceous or crustaceous, the posterior extremity being membran- 

 ous and forming a sort of an appendage to them; they almost always 

 decussate; those of the other Hemiptera are simply thicker and 

 larger than the wings, semi-membranous, like the elytra of the Or- 

 thoptera, and sometimes opaque and coloured, sometimes transparent 

 and veined. There are a few longitudinal plicee in the wings. 



Several have ocelli, 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 develop- 

 ment and growth of the volume of the body. 



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 famihes, 



FAMILY I. 



GEOCORIS^. 



In this family the antennas 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. 

 This genus (an example of which may be found in our common Squash- 



