3I0SQUIT0ES IN GENERAL 



45 



The question was finally set at rest by Macloskie (1887), 

 wlio succeeded in demonstrating a poison gland in mos- 

 quitoes and in showing that this poison gland is connected 

 by a duct with the mouth-parts. This venemo-salivary 

 duct is very fine, running backward in the lower i^art of 

 the head in the throat and terminating in the prothorax 

 in glands of characteristic structure. The glands are in 

 two sets, each set consisting of three glands, two of which 



Fig. 2. — Section of head of Mosquito showing poison 

 enlarged. (Redrawn from Macloskie.) 



fhind at 



are ordinary salivary glands and the third (between the 

 other two) having a difterent appearance and structure 

 and secreting the poison. 



Miall, of England, as late as 1895 stated that it could 

 not positively be said whether poison is injected into the 

 wound or not. Overlooking, or not accepting, Macloskie 's 

 demonstration, he says : " No poison has hitherto been 

 demonstrated, and there is some reason to believe that the 



