BITING MIDGES — WIRTH AND BLANTON 369 



Wing. — Pattern as figured ; second radial cell very dark ; radial cells 

 broad, the second very broad, the first about twice as long as the 

 second; r-m crossvein blackish, in the center of a large pale spot 

 which broadly reaches costal margin; cell R5 with five definite pale 

 spots, one resting on anterior side of vein Mi near base of cell, the 

 next three arranged in an arc behind and around the apex of second 

 radial cell and the fifth spot lying in middle of distal portion of cell R5, 

 not reaching wing marf In ; two pale spots in cell Mi, the distal one lying 

 far from wing margin ; apices of veins Mi and M2 pale margined a short 

 distance; one pale spot each in apex of cell Mo and cell M4, neither 

 attaining wing margin; two pale spots in distal portion of anal cell and 

 two in basal portion of this cell; cell M2 with a pale spot lying in 

 front of mediocubital fork, one lying behind medial fork and another 

 lying across cell about halfway from these spots and wing base. 

 Macrotrichia sparse on distal third of wing; costa extending to 0.70 

 (0.69-0.72, n=8) of distance to wing tip. Halter pale. 



Abdomen. — Brownish black, cerci whitish. Spermathecae two, 

 pyriform, slightly unequal, measuring 0.063 by 0.043 mm. and 0.059 

 by 0.042 mm., the bases of the ducts sclerotized a short distance. 



Male genitalia: Ninth sternum with a shallow caudomedian 

 excavation; ninth tergum quadrate, with large, triangular apicolateral 

 processes. Basistyle with ventral root large, foot-shaped ; ventral root 

 slender; dististyle long and slightly curved with pointed, bent tip. 

 Aedeagus with rounded basal arch extending to a third of total length, 

 the basal arms stout and curved ; distal portion with four long, tapering 

 pointed branches, the median pair cleft about half the distance from 

 their apices to the arch, the lateral pair arising nearer to arch. Para- 

 meres each with very large basal knob, stem curved near base, only 

 slightly swollen on curved portion, midportion of stem slightly sinuate, 

 slender, without ventral lobe, the distal apex with a lateral fringe of long 

 spines. 



Distribution: Brazil; Mexico; Panama; Venezuela. 



Panama records: 



BocAS DEL ToRO PROVINCE: Almirante. 



Canal Zone: Fort Davis, Fort San Lorenzo, Fort Sherman, Loma Boracho, 



Mojinga Swamp. 

 Dari^n Province: El Real, Jaque. 

 Panama Province: Arraijdn, La Jolla. 



Discussion: Culicoides carsiomelas Wirth and Blanton resembles 

 acotylus in having an unmarked brownish mesonotum, darkened cross- 

 vein and the same general wing pattern, but can be readily distin- 

 guished by the presence of only one pale spot in the distal part of the 

 anal cell, by the presence of two distal pale spots in cell M2, and the 

 presence of five rather than three pale spots in cell R5. 



