Mosquitoes and Malarial Fever 489 



the general principles of entomology. The best works of reference 

 for this purpose, that have come under observation to the present 

 time are "A Text-book of Medical Entomology" by Patton and 

 Cragg, published by the Christian Literature Society for India, 

 London, Madras and Calcutta, 1913, and the " Handbook of Medical 

 Entomology" by Riley and Johannsen, the Comstock Publishing 

 Co., Ithaca, New York, 1915. 



The mosquitoes comprise a family of dipterous or two-winged 

 insects, included in the family Culicidae. They can be recognized, 

 first by their well-known general form, and second by the presence 

 of scales upon some part of the head, thorax, abdomen, and wings. 

 For the rough and ready identification of the larger groups and 

 principal genera, the following table compiled from various authors 

 may answer. For more precise information and for the identifica- 

 tion of the species, of which hundreds are now described, reference 

 must be made to the large works recommended above. 

 CLASSIFICATION (Stitt) 



There are four subfamilies of CULICIDAE, differentiated according to the 

 *>alpi : 



I. Palpi as long or longer than the proboscis in the male. 



1. Palpi as long as the proboscis in the female; 



proboscis straight .......................... ANOPHELIN^E. 



2. Palpi as long or shorter than the proboscis; 



proboscis curved .......... . ................ MEGARRHININ.-E. 



3. Palpi shorter than the proboscis ................ CULICIN^E. 



II. Palpi shorter than the proboscis in the male and female ^DIN^E. 



Of these the Anophelinae is the one family concerned in the transmission of 

 malarial fever, so that it is important to be able to differentiate the genera in- 

 cluded in the family. 



ANOPHELINAE 



1. Scales on head only; hairs on thorax and abdomen. 



1. Scales on wings large and lanceolate. Palpi only 



slightly scaled ............................... Anopheles. 



2. Wing scales small, narrow, and lanceolate. Only a 



few scales on palpi ............................ Myzomyia. 



3. Large inflated wing scales ......................... Cydoleppteron. 



2. Scales on head and thorax. Scales narrow and curved. 



Abdomen with hairs, not scales. 

 i. Wing scales small and lanceolate ................... Pyretophorus. 



3. Scales on head, thorax, and abdomen. Palpi covered 



with thick scales. 



1. Abdominal scales on ventral surface only. Thoracic 



scales like hairs. Palpi rather heavily scaled.. . .Myzorrhynchus. 



2. Abdominal scales narrow, curved or spindle shaped, 



in tufts and dorsal patches .................... Nyssorrhynchus. 



3. Abdomen almost completely covered with scales and 



also having lateral tufts ............. . ......... Cellia. 



4. Abdomen completely scaled ....................... Aldrichia. 



Species of the genera Anopheles, Myzomyia, and Myzorrhynchus, are known 

 to transmit malarial parasites. The Culicinae include Stegomyia and Culex, 

 which have some medical interest, as the former transmits yellow fever and the 

 latter, filarial worms. 



CULICINAE 



I. Posterior cross-vein nearer the base of the wing than the 

 mid-cross-vein. 



