io6 



NORTH AM URIC AN DIPTERA. 



Head well formed, enclosed in a ehitinous covering; 

 with compound eyes, single-jointed antennae, a group of 

 ' hairs before the oral orifice, toothed mandibles, maxillae, 

 and single-jointed palpi. Thoracic segments consolida- 

 ted into a transversely elliptical flattened mass; abdomen 

 with nine slender and moniliform segments, the eighth 

 with a dorsal, respiratory opening, often prolonged into 

 a ehitinous tube; last segment furnished with a ehitin- 

 ous plate, and usually with four delicate anal append- 

 ages. The body has setae in tufts or singly, usually 

 more or less conspicuously feathered. From other aquatic 

 nematocerous larvae, the mosquitoes are distinguished 

 by the presence of the mouth-brush, the shape of the 

 anal segment and the absence of abdominal feet. The 

 larvae of Dixa and the Corethrinae are practicably indis- 

 tinguishable from those of the Culicinae, save by minor 

 characters.* 



Pig. 35. Culicidte. 1, Megarhinus, wing; 2, Megarhinus, head, 

 male; 3. . ledes, winy; 4. Hcemagogus, bean, female; 5. front claws 

 of ftcemagogus, male; 6, Wyeotnyia, head of female; 7, Corethra, hind 

 tarsus. 



TABLE OF GENERA. 

 Proboscis short, not adapted for piercing. . . Corethrinae. 

 Proboscis much longer than the head, firm, adapted for piercing. 

 Mosquitoes Culicinae. 



*I especially commend to the student interested in this family of flies 

 the comprehensive and richly illustrated Report upon the Mosquitoes 

 of New Jersey (1904), by Prof. J. B. Smith. 



