142 American Midland Naturalist Monograph No. 3 



caudal tuft on either side; ventral brush extending almost the entire length of 

 the anal segment; gills 4, longer than the anal segment, pointed. 



distribution. — Southern United States, north to Indiana and Kansas; 

 Mexico; Central and South America. Southern States: Alabama (170); 

 Arkansas (30); Florida (35); Georgia (97); Kentucky (140); Louisiana and 

 Mississippi (52); Missouri (1); North Carolina (166); South Carolina and 

 Tennessee (125); Virginia (49). Other States: Indiana (76); Kansas (79); 

 Oklahoma (159); Texas (108). 



BIONOMICS. — This species is more abundant in certain areas of Alabama, 

 Mississippi, Louisiana and Arkansas than in the Atlantic and Gulf coastal 

 plains. The females are vicious biters and will engorge themselves until they 

 are barely able to fly. The adults are often so plentiful in certain areas follow- 

 ing prolonged summer rains, that they seriously annoy livestock and interfere 

 with farm work. They are more commonly encountered in woodlands and 

 thickets but will come out into open fields to attack. The larvae are found in 

 temporary rain-filled pools in the southern states from May to October (4th 

 Sv. C. Med. Lab. records, 1942-1944, unpublished). 



Psorophora (JanthinosOma) ferox (Humboldt) 



Culex ferox Humboldt, 1820, Voy. Reg. Equin., 7:119. 



ADULT FEMALE. — Medium sized species. Head: Proboscis dark scaled; 

 palpi short, dark, about one-fifth as long as proboscis. Occiput clothed with 

 numerous broad recumbent whitish-yellow to golden-yellow scales, paler anter- 

 iorly; many yellow erect forked scales present on posterior half. Thorax: Scu- 

 tum covered by rather broad dark-brown and golden-yellow (often whitish- 

 yellow) scales, intermingled and in no definite pattern, the dark scales more 

 abundant. Abdomen: All tergites (first included) dark scaled with purplish 

 reflections, except for prominent apico-lateral triangular patches of whitish- 

 yellow to golden-yellow scales; sternites yellow scaled on segments II to VI, 

 mainly dark on segment VII. Legs: Knee spots present on middle and hind 

 legs; inner surfaces of all femora primarily pale scaled, darker near apices; outer 

 surfaces of femora I and III usually pale scaled on basal third or half. Tibiae 

 and tarsi of fore and middle legs entirely dark scaled; segments 4 and 5 of hind 

 tarsus, and frequently the apex of segment 3, white scaled, other segments dark 

 (Fig. 73 A); segments 1 and 2 of hind tarsus and apical portion of hind tibia 

 with scales suberect, appearing rather shaggy. Wing: Scales dark, narrow. 



ADULT MALE. — Coloration similar to that of female. TERMINALIA (Fig. 

 73B). Ninth tergite (IX-T) with lobes (IXT-L) widely separated, broadly 

 rounded, each bearing many scattered setae. Tenth sternite (X-S) prominent, 

 heavily sclerotized. Phallosome (Ph) heavily sclerotized, conical, broad basally 

 and pointed apically, open ventrally, closed dorsally. Claspette (CI) slender, 

 cylindrical, about three-fourths as long as basistyle, becoming abruptly broader 

 at apical fourth, then tapering to tip; apical fourth with numerous slender, 

 feathered filaments on inner margin; a large leaf-like contorted pointed fila- 



