428 THE ANIMAL PARASITES OF MAN 



told by the whole body being more or less covered with long twisted scales, 

 giving them a mouldy appearance, and the legs densely scaled with out- 

 standing scales ; the wings with large parti-coloured scales. The Australian 

 M. alternans, Walker, occurs in larval forms both in fresh and salt water. 

 The adults bite man. 



Genus Psorophora, Robineau-Desvoidy. 



This genus is confined to the Americas and the West Indies. Four 

 species exist which can easily be told from Mucidus by the absence of long 

 twisted scales and the narrower wing scales. The legs are densely scaled 

 and the thorax ornamented with flat spindle-shaped scales. 



Psorophora ciliata, Robineau-Desvoidy, occurs in both North and South 

 America, and bites man. 



Genus Janthinosoma, Arribalzaga. 



Hind legs only densely scaled ; some of the hind tarsi are always white. 

 The venation is as in Culex. The abdomen is metallic and iridescent. 

 They all bite man and occur only in the Americas and West Indies. 



Genus Stegomyia, Theobald. 



After Anopheles this is the next most important genus, on account of the 

 connection of 5. fasciata with yellow fever. This genus is easily told by 

 the head and scutellum being entirely clothed with flat scales. They are 

 mostly black and white mosquitoes, and are known in India as tiger mos- 

 quitoes. The best known species is S. FASCIATA ; it is found in all parts of 

 the world between 40 N. and S. It is a most vicious biter both by day 

 and night, and breeds in small artificial collections of water, such as barrels, 

 puddles, cisterns, and even in such small receptacles as sardine tins. The 

 character by which this species is told is the ornamentation on the thorax, 

 which has a curved silvery line on each side and two dull yellow parallel ones 

 in the middle ; but it is subject to much variation, some specimens (variety 

 mosquito} having no median thoracic stripes. 



Stegomyia scutellaris, Walker. 



A vicious biter, found in India, China, Malay, and East Indies, Fiji and 

 Ceylon. The thorax has one median silvery stripe, and so can easily be 

 told from 5. fasciata. ^ 



A number of nearly allied genera occur here (vide synoptic table). 



Genus Theobaldinella, B\o.i\ch3ird==Theobaldia, Neveu-Lemaire. 



. Includes several large Culicines, of which T. annulata, Meigen, is the 

 type The wings are usually spotted (annulata, incident, &c.), but may 

 be nearly plain (spathipalpis\ The $ have the palpi swollen apically, and 

 the $ have long five- join ted palps. 

 Several of these are vicious biters. 



