188 MEDICAL ENTOMOLOGY 



male, but rarely with more than two serrations. The wings are long 

 and narrow, and when at rest folded flat on the abdomen ; the venation is 

 characteristic and constant; six longitudinal veins are nearly always 

 present, the second, fourth and fifth \are forked ; the third is simple and 

 arises from the anterior cross-vein about the middle of the wing ; two 

 basal cells are nearly always present. The veins are clothed with hairs 

 or true scales, and the hind margin is fringed with scales or simple hairs. 



At present the family Culicidae contains about 1250 known species 

 distributed all over the world. 



The Culicidae, like many of the other families of the Diptera, contains 

 species which show minor differences in structure, the value of which 



is a matter of dispute. Dipterologists, however, have 

 Classification of the , , c .,. r ,, 



. .. .. been content to recognize two subfamilies of the 



Culicidae, the Corethrinae in which the proboscis is 

 soft and not armed for piercing, and the Culicinae in which it is long 

 and is, at least in the female, armed for piercing. 



The blood-sucking habit of the female mosquito, and the relation of 

 certain species with the transmission of the parasites of malaria, yellow 

 fever and filariasis, have stimulated the study of these insects, with the 

 result that workers of all nationalities have collected them from all parts 

 of the world. In order to facilitate this study and to make the work of 

 others accessible, Theobald has written an exhaustive monograph of the 

 group, in five volumes, classifying them according to the structure and 

 position of the scales on the various parts of their bodies. In Volume I 

 of his work, The Culicidae of the World, he recognizes six subfamilies 

 of the Culicidae, of which the Corethrinae is one, and this grouping is 

 retained in Volume III published in 1903. In 1905 Eysell published a 

 paper in which he suggested the separation of the Corethrinae from the 

 Culicidae, raising them to family rank ; the family Culicidae being retained 

 for mosquitoes alone. Theobald in Volume IV of his monograph, pub- 

 lished in 1907, following this suggestion, divided the family Culicidae 

 into ten subfamilies and more than one hundred genera, many of which 

 are subdivisions of the older genera. In Volume V, published in 1910 he 

 retains this classification but adds several new genera. 



Dipterologists have taken exception to this classification. Williston, 

 for instance, points out that scale characters are highly artificial, and 

 that a genus of mosquitoes cannot be raised to family rank without 

 raising all other genera of equal rank in a like manner. Whether the 

 classification based on the characters of the scales, resulting as it has 



