246 THE MOSQUITOES. 



In the female mosquito, the parts withdrawn may seem to be largely 

 made up of the white oval ovaries. These are connected with the 

 spermathecae, in which the spermatozoa are stored after fecundation by 

 the male. In the male the testicles are quite distinct. Next to the 

 examination of the stomach for zygotes, which appear as wart-like 

 excrescences on its outer surface, the most important structures are the 

 salivary glands, where the malarial sporozoites are found. The 

 easiest way to dissect out the salivary glands is to press down firmly, but 

 gently, on the anterior part of the thorax, and then with the shaft of a 

 second needle, pressing on the head, to gently draw the head away from 

 the thorax, so that by this expression and traction movement you 

 extract them with the head segment. They are very minute and are to 

 be told by their exceedingly highly refractile appearance. To stain for 

 spcrozoites, pick up the head end, and with forceps draw the severed 

 neck along a clean dry slide, trying at the same time to smear out the 

 adherent salivary glands. After drying, stain with Wright's stain. 

 The sporozoites are narrow falciform bodies about 12 p in length, 

 with a central chromatin dot. 



A matter about which there is dispute is as to whether the salivary 

 glands communicate with the alimentary canal. Theobald states 

 that there is no connection between them. 



DIFFERENTIATION OF CULICIN^: AND ANOPHELIN^:. 



It is impossible even for an entomologist to differentiate mos- 

 quitoes without recourse to elaborate keys and tables. It is a com- 

 paratively easy matter, however, to decide as to whether the mosquito is 

 a probable malaria transmitter or not. 



While certain characteristics of the male are used to separate the 

 ^dinae from other subfamilies, yet it is only with the female that we 

 concern ourselves in differentiating the Culicinae from the Anophelinac. 

 Therefore, it is first necessary to distinguish the male from the female. 

 If the antennae have not been torn off, this can be decided by the 

 highly-adorned plumose antennae of the male, those of the female being 

 sparsely decorated with short hairs. The palpi of the Anophelinae tend 

 to be clubbed, while those of the Culex are straight. If the antennae 

 have been broken off, look for the claspers at the end of the abdomen. 



