STEGOMYIA 



315 



Differentiation of Culicinae Genera. 



i. Posterior cross-vein nearer 

 the base of the wing than 

 the midcross-vein. 



1. Proboscis curved in female. Psorophora. 



2. Proboscis straight in female. 



A. Palps with three segments in the female. 



a. Third segment somewhat longer than 

 the first two. Culex, 



b. The three segments equal in length. 

 Stegomyia. 



B. Palps with four segments in the female. 



a. Palps shorter than the third of the pro- 

 boscis. Spotted wings. Theobaldia. 



b. Palps longer than the third of the pro- 

 boscis. Irregular scales on w i n g s . 

 Mansonia, 



C. Palps with five segments in the female. 

 Taniorhynchus. 



2. Posterior cross- vein in line with midcross-vein. Joblotina. 



3. Posterior cross- vein further from base of wing than midcross-vein. 



Mucidus. 



Of the Culicinae the genus Stegomyia is of importance on account 

 of yellow fever. The totally efficient hosts for filariasis (filarial embryos 

 found in the thorax and proboscis) are chiefly among the genus Culex. 

 The genera Mansonia and Taeniorhynchus may also transmit filariasis. 

 Some think the Anophelinae genera "Cellia" and "Myzomyia" may 

 transmit filariasis as well as malaria. 



The genus Culex is implicated in dengue. 



Stegomyia. This is the most important culicine genus. These are mosquitoes 

 with silver markings. The head, entirely covered with flat scales, has also some 

 upright forked scales. Scutellum has dense flat scales. S. calopus is deep blackish- 

 brown with two thoracic parallel lines with curved silver-white lines outside (lyre 

 marking). Banding of thorax, abdomen, and legs. 



S. calopus bites only at night after the first feeding. The first meal of blood 

 however may be taken in the day time. To become infected it must take blood 

 from a yellow-fever patient in the first two or three days of the disease. After 

 sucking the blood of a yellow-fever patient the mosquitoes cannot transmit the 

 disease by biting a nonimmune to yellow fever for a period of eleven days. After 

 this time the mosquito remains infective for its life in one instance 57 days. 



S. scutellaris has a single silver stripe down the center of thorax. Mosquitoes 

 of this genus are often called "Tiger mosquitoes." The larvae have short, barrel- 

 shaped siphons. They breed particularly in receptacles about the house. 



S. pseudoscutellaris, which resembles S. scutellaris, but has white bands only, 

 at the sides of the abdominal segments, is thought to transmit filariasis in Fiji. 



Cidex. Male palpi long and acuminate. Head has narrow curved and up- 



