36 MOSQUITO ERADICATION 



distinguished from Anopheles mosquitoes by the fact that the 

 palpi are rudimentary. 



Being smallish, A. calopus can pass through a screen composed 

 of 16 strands or 15 meshes to the inch. To be effectual, there- 

 fore, screens should have more than 15 meshes to the inch. 



As a rule, A. calopus does not fly nearly so far as the malaria- 

 carrying mosquitoes, manifesting an apparent desire to remain 

 about the environment that gave it birth. It is active chiefly 

 during the daj'-time, resting at night, unless attracted by bright 

 lights. During the day-time it seeks shade, since it cannot 

 survive long in the direct sunlight. It is, therefore, chiefly 

 dangerous in houses or in brush, etc. 



Rosenau 1 says: "It ma} r possibly at times fry across the street, 

 but it is evident that it neither flies far nor is it ordinarily trans- 

 ported to any great distance on railroad cars, although it may be 

 carried over seas in ships." 



CULEX FATIGANS WIED. (C. QUINQUEFASCIATUS SAY) 



This mosquito is believed to transmit both dengue and filariasis 

 to man. It is very widely distributed over the tropics and sub- 

 tropics. C. fatigans and A. calopus are two of the commonest 

 house mosquitoes in the Southern States. 



While these two species are constantly associated in that 

 section, breeding together in house-yards in the same water and in 

 the same containers, A. calopus has been exonerated as a dissemi- 

 nator of dengue and filariasis, while C. fatigans has been found 

 to be almost wholly responsible for the spread of these diseases. 



C. fatigans, like A. calopus, is essentially a domestic mosquito, 

 breeding in fresh water in back-yards, in cisterns, rain-water 

 barrels, tin cans and other miscellaneous artificial containers. 



C. fatigans is a smallish to medium-sized mosquito, ranging 

 in color from yellow to dark-brown, with light bands at the base 

 of each segment. Its legs and proboscis are not banded. 



Probably the quickest way of distinguishing C. fatigans from 

 A. calopus is by the fact that the former is essentially a night- 

 biter, while the latter is a day-biter. This is very perceptible, 

 wherever the two occur together. 



The larva of this species may be distinguished from that of A. 

 calopus by the fact that its respiratory siphon is brownish and 

 nearly three times as long as it is broad. 



1 "Preventive Medicine and Hygiene," New York and London, 1918. 



