286 Hominoxious Arthropods 



h. R4+s does not form an angle at the crossvein. On birds. 

 There is a record of one species of this genus attacking man 

 .................................... Ornithomyia Latr. 



hh. R 4 + s makes an angle at the crossvein. 0. confluens. 

 . .'. ................................... Ornithoica Rdi. 



ff. Anal cell not closed by an anal crossvein. Lynchia, Pseudolfersia, 

 and Olfersia are chiefly bird parasites. The first mentioned 

 genus is said to be the intermediate host of Hamoproteus columba. 

 aa. Abdominal segments chitinous; not parasitic in the adult stage. 



b. Antennae with six or more segments and empcdium not developed pulvilli- 



form; palpi often with four segments. 

 c. Ocelli present. BLEPHAROCERIDJE, RHYPHID^E, BiBiONiDyE, MYCETO- 



PHILID/E, besides some isolated genera of other families. 

 cc. Ocelli absent. 



d. Dorsum of the thorax with a V-shpaed suture; wings usually with 

 numerous veins; legs often very long and slender. Crane flies. 

 .................................................. TIPULID^E 



dd. Dorsum of the thorax without a V-shaped suture. 



e. Not more than four longitudinal veins ending in the wing margin; 

 wing usually hairy: antennae slender; coxae not long; tibiae with- 

 out spurs, legs long and slender. Small, delicate flies often called 

 Gall gnats .................................... CECIDOMYIID^E 



ee. More than four longitudinal veins ending in the wing margin. 

 f. The costal vein is not produced beyond the tip of the wing; radius 



with not more than three branches. 



g. Antennae short, composed of ten or eleven closely united seg- 

 ments; legs stout; body stout; abdomen oval; anterior 

 veins stout, posterior ones weak (fig. 163 b); eyes of the male 

 contiguous over the antennae. Black flies, buffalo flies, 

 turkey gnats. Many North American species, several of 

 them notorious for their blood sucking propensities ...... 



............................................ SlMULIID^E 



h. Second joint of the hind tarsus with basal scale-like process and 

 dorsal excision (fig. 161 h); radial sector not forked; no 

 small cell at the base of the wing. 5. forbesi, jenningsi, 

 johannseni, meridionale, piscicidium, venustum, vittatum, 

 etc. Widely distributed species ....................... 



........................ ( =Eusimulium) Simulium Latr. 



hh. No basal scale-like process on the second joint of the hind 



tarsus; radial sector usually forked (fig. 163 b). 



i. Face broad, small basal cell of the wing present. P. fulvum, 



hirtipes, mutatum, pecuarum, pleurale . . Prosimulium Roub. 



ii. Face linear; small basal cell of the wing absent. One 



species, P. furcutum, from California ................ 



.............................. Parasimulium Malloch 



gg. Flies of a different structure. 



h. Antennae composed of apparently two segments and a terminal 

 arista formed of a number of closely united segments. 

 Rare flies with aquatic larvae ........ ORPHNEPHILID^; 



