A REVISION OF THE GENUS LEPTOCONOPS, SKUSE. 7 



The confusion which has arisen in regard to the segmentation of the palj^i has been 

 entirely due to the somewhat rudimentary nature of the first and second segments, 

 and to the varying degrees of differentiation exhibited by them in certain species. 

 The palpi have thus been described as possessing four, three, or even two segments, 

 when the basal ones were overlooked or ignored. 



J^:}C 



Fig. 3. Proximal portion of antenna of Acanihoconops albivenins, Meij., 

 §, showing the reduced first segment ; side view ( x 510 circa). 



Antennae set in large subcircular, pale-coloured, thinly chitinised, depressed areas. 

 In the female the antennae (fig. 5, a-h, and cf. fig. 1) are pilose, composed of thirteen 

 (subgen. Holoconops) or fourteen {Leptoconops, sens, sir.) segments ; first segment 

 (cf. fig. 3) (ignored by all previous authors except Lutz) cup-like, broad at the apex, 

 where there is a rim of thickened chitin, narrowing rapidly to a conical base ; second 

 segment large and rounded, the inter-segmental membrane connecting it to the 

 chitinised rim of the first, extensive ; segments of the ifagellum eleven or twelve in 

 number, all but the last with a distinct whorl of hairs and two or more transparent 

 spines ; third segment (first of the flagellum) relatively large, pyriform ; terminal 

 segment elongate-oval, considerably longer than any of the others; intermediate 

 segments (4 to 12 or 13) almost uniform in shape and size, often transverselv oval or 

 subspherical, rarely narrowly oval. In the male the antennae are longer and plumose, 

 composed of fifteen segments ; the two basal segments similar to those of the female 

 but larger, the second very large ; segments of the flagellum as shown in fig. 4, k, 

 and described on pp. 16 and 17. 



Thorax arched anteriorly but not projecting over the head, with short and some- 

 what sparsely arranged hairs on the dorsal surface. Situated laterally, near the 

 anterior margin, and centrally, in front of the scutellum, are small depressions some- 

 what similar to those found in Culicoides ; in each anterior depression, however, are 

 two or three separate oval or rounded, seemingly membranous, areas (which frequently 

 appear as small shining black spots in dry specimens), not a single slit-like area as in 

 Culicoides. Scutellum with the posterior margin gently rounded, slightly produced 

 laterally, bearing two or three pairs of strong, and sometimes a few pairs of smaller, 

 bristles. Post-scutellum strongly arched, nude. 



Wings white, iridescent, with the surface entirely covered with minute upright 

 setae and with a fringe of longer hairs on the distal and posterior margins. The 

 venation (fig. 7) is characteristic, but the veins, particularly the anterior ones, are ill- 

 defined and difficult to distinguish. They can best be followed in dry specimens, but 

 careful manipulation is necessary, as the detection of certain details depends largelv 

 on the angle of view and the illumination ; in mounted specimens (unless stained) the 

 venation cannot be observed. The costa is short and, in the female, usually terminates 



