MOSQUITOES AND FLIES 



muscles. The true sucking organ lies within the head 

 (Pmp), and does not differ in structure from that of other 

 flies. 



While our indictment of the flies has applied thus far 

 only to the insects in the mature form, there are species 

 which, though entirely innocent of any criminality in their 



Lm 



Fie. 186. Head and mouth parts of the tsetse fly, Gloisina 



A, lateral view of the head and proboscis (Prb) of Glossina palpalis, 



male 



B, cross-section of the proboscis of Glossina fusca (from Vogel), 

 showing the food canal (FC) inclosed by the labrum {Lm) and 

 labium (Lb), and containing the tubular hypopharynx (Hphv) 



through which the saliva is injected into the wound 



C, mouth parts of Glossina palpalis, with the parts of the proboscis 

 separated. b, basal swelling of the labium; La, the labella, or 

 terminal lobes of the labium used for cutting into the skin of the 

 victim; Lb, labium; Lm, labrum; Pip, maxillary palpus (the 



maxillae are lacking); Pmp, mouth pump 



[351] 



