Groups IV, V. 



which most closely approaches nigerrimus in its structure and habits, 

 and practically simple and unbranched in the case of theobaldi and 

 maculatus which in their habits ( being for the most part stream 

 breeders ) most closely approach the next group. 



The larvae of the majority of the members of this group are 

 found in deep green pools, tanks, lakes, etc., but maculatus and theo- 

 baldi are frequently found in streams. The shape of the eggs of 

 this group vary considerably, but the majority have rather a narrow 

 deck surface, and the lateral floats encroach upon this surface that 

 is, they are placed high up on the sides of the egg. 



Observations. Certain seasonal variations have been noted in 

 Juliginosus which so alter the appearance of this mosquito that 

 the winter form might have been considered as a distinct species 

 on as good grounds as those upon which some species are at present 

 differentiated from one another. 



There can be little doubt that some of the types we have de- 

 scribed may be shown simply to be a seasonal, geographical, or other 

 variation of some other type. 



We would specially draw attention in this connection to theo- 

 baldi and maculatus, which seem to have distinct and separate geo- 

 graphical distributions. 



A. fuliginosus is the only member of this group which has, up 

 to the present, been found infected in nature with sporozoites resem- 

 bling those of malaria. 



GROUP V. 



This is by far the most important group of "anopheles" because 

 of the marked malaria-carrying powers of its members. They have 

 frequently been found infected with sporozoites in nature and are, as 

 a rule, abundantly found in all notoriously malaria-infected localities. 

 They are all rather small, very dark mosquitoes, and when resting 

 on any surface they are very difficult to detect. 



These mosquitoes are typical stream breeders, but culicifacies 

 can accommodate itself to almost still water. The larvse have simple 

 unbranched frontal hairs, except in the case of jeyporiensis which 

 has branched frontal hairs. Palmate hairs are present on all the 

 abdominal segments except the eighth, and a pair also is found on 

 the thorax. These hairs are very large and well developed in all 

 except culicifacies. 



70] 



