36 



MALARIA 



have spotted wings. A Culicine mos- 

 quito, Theobaldia incidens, very com- 

 monly found in California, has con- 

 spicuously spotted wings. 



Sexual Differences. --The males of 

 fig. 13. varieties of a jf spec i es f mosquitoes, as far as 



Culicid scales. a, b, c, r 



head scales: (a) narrow known, are provided with plumose 



curved ; (b) upright forked ; r 



(c) flat; (d-h) thoracic an t enn c€ (Fig. 11, b) , while in the fe- 



scales. (Redrawn after v ° 



Stephens and christo- ma j e these organs are slender, thread- 



phers.) ° 



like, and covered only with short 

 lateral hairs. In the males the palpi are long (as long 

 as or longer than the beak) conspicuous, jointed organs, 

 and quite hairy (Fig. II, b). In habit the sexes differ 



Fig. 14. Occurrence and arrangement of scales on the head, (a) Stegomyia; (b) 

 Anopheles; (c) Culex. (Redrawn in part after Stephens and Christophers.) 



quite markedly ; the males do not feed upon blood, and 

 are consequently less frequently found around human 

 habitations. Sweeping with the insect net through 



