202 ENTOMOLOGY FOR MEDICAL OFFICERS 



or burred near the tip — are long, pointed bristles, and it is 

 with these that the bug usually sucks. The mandibles are 

 longitudinally grooved along their opposed surfaces — the 

 groove being " double-barrelled " — so that when they are 

 apposed two tubes are formed, down one of which the 

 saliva runs while the desired juice is sucked along the other. 

 The maxillae embrace and support the mandibles. The 

 labrum is present, but is quite short. 



All 3 thoracic segments are distinct, though the posterior 

 segments are often more or less hidden by the hardened 

 bases of the front wings. The prothorax is free, and the 

 mesothorax is commonly produced behind to form a 

 scutellum. 



The abdomen is commonly flat, and its lateral margins 

 are often produced to form a sort of thin shelf or connexivum. 



Fm. 85.— Mouth-parts of Bed-bug, dissociated. 



The odour emitted by many bugs comes from the 

 secretion of certain glands which, in the adult, open on the 

 sternum of the last thoracic segment. 



There are two distinct suborders of Rhynchota, namely, 

 the Heteroptera (ere/oo? = diverse, and ■7rTep6u = a. wing), in 

 which the front wings, when present, are hardened at base 

 to form wing-covers or elytra, and the beak is merely 

 reflexed ; and the Homoptera {6iJ.6i = one and the same, and 

 TTTepov), in which the wings, when present, are of one 

 consistence, and the beak is so much bent under that it 

 appears to spring from the posterior border of the head. 



Rhynchota Heteroptera. 



This suborder includes the true bugs. The hardened 

 basal part of the front wing is known as the elytrum 



