THE RHYNCHOTA. 385 



base of the rostrum its upper edges are usually sepa- 

 rated by a small interval; this is filled up by the 

 labrum, which is generally rather long and of a taper- 

 ing form. The efficient organs are the four bristles 

 contained within the jointed rostrum; by means of 

 these the insect wounds the tissues of the plants or 

 animals upon whose juices it desires to feed ; these 

 are then sucked up by the assistance of a vesicular 

 appendage or sucking stomach attached to the oeso- 

 phagus, the rostrum merely serving, like the tip of 

 the proboscis of a fly or gnat, to guide and support 

 the delicate bristles as they are pushed forward by 

 the action of their muscles. 



In the structure of the rest of their bodies the 

 insects belonging to this order exhibit a great diver- 

 sity, but the three regions are usually distinctly 

 marked, and the segments of the thorax and abdomen 

 are almost always separate. The head is very variable 

 in form ; it bears a pair of antennae and compound 

 eyes, and usually two or three ocelli or simple eyes. 

 The legs are generally constructed only for walking, 

 although the fore-limbs are sometimes converted into 

 raptorial, or the hinder ones into leaping organs ; and 

 in the aquatic species the latter are elongated, flat- 

 tened, and fringed, as in the Water-Beetles, with stiff 

 hairs, rendering them efficient organs of natation. 

 The tarsi never consist of more than three joints. 

 The wings are almost always present, and usually four 

 in number, although in a good many species the 

 hinder pair are deficient, and in a few we find no 

 wings at all. In their structure they present con- 

 siderable differences in different groups, and these 

 differences present one of the most striking characters 

 upon which the division of the Rhynchota into two 



