BITING MIDGES — WIRTH AND BLANTON 397 



a very narrow transverse pale mark across extreme apex of wing. 

 Macrotrichia very scanty, only a few in apices of cells R5 and Mj; 

 costa extending to 0.71 (0.70-0.74, n = 9) of distance to wing tip. 

 Halter pale. 



Abdomen. — Brownish black. Spermathecae two, pyriform, un- 

 equal, measuring 0.063 by 0.039 mm. and 0.052 by 0.038 mm., the 

 bases of the ducts sclerotized a very short distance. 



Male genitalia : Ninth sternum with very broad, shallow, caudo- 

 median excavation, the posterior membrane spiculate; ninth tergum 

 short and tapered, with very long, slender, fingerlike, closely ap- 

 proximated, apicolateral processes. Basistyle with ventral root 

 very slender, long and pointed, dorsal root stouter and about half as 

 long; dististyle curved, tapered to slender point. Aedeagus with 

 basal arch about 1.5 times as broad as high, basal arms very short 

 and curved; distal portion very broad, about twice as long as broad, 

 with truncated apex. Parameres each with very broadly expanded, 

 laterally directed basal knob bearing a distinct anterior process, stem 

 very short, swollen at base, stout on distal portioa with extreme tip 

 expanded and abruptly bent laterad in the shape of a beak. 



Distribution: Panama. 



Panama records: 



BocAS Del Toro Province: Almirante. 



Canal Zone: Fort Davis, Fort Sherman, Loma Boracho, Mojinga Swamp (type 



locality). 

 DARifiN Province: Punta Patino. 

 Panama Province: Tooumen. 



Discussion: The relations of macrostigma are uncertain, but this 

 species is probably related to mojingaensis Wirth and Blanton and 

 bricenoi Ortiz. Features which support its assignment to the group 

 with these two species are the basic arrangement of the four pale 

 spots in cell R5 with two spots behind the second radial cell, the 

 sensorial pattern with sensoria present on segments iii, viii-x, the 

 shape of the male aedeagus, the long male apicolateral processes and 

 the spiculate membrane on the ninth sternum. The male parameres 

 are bluntly expanded apically as in bricenoi, but in a different shape. 

 The shape of the basal knob of the paramere as well as the long 

 slender simple ventral root of the male basistyle are quite different, 

 however, and prevent macrostigma from being assigned to this group 

 with any degree of confidence. 



The furens group 



This group consists of small to medium-sized species, frequently 

 with pale spots at the extreme apices of cells R5 and Mi and a mesonotal 

 pattern of small punctiform brown dots; female antenna with sensoria 



475684 0-59-11 



