INSECUTOR INSCITI^ MENSTRUUS 33 



Culex (Culex) thriambus, new species. 



Female. Proboscis black above, broadly whitish in the 

 middle below, the white rarely nearly or wholly encircling the 

 organ in a narrow ring. Mesonotum with brown scales. Ab- 

 domen with basal segmenttal white bands, widening on the 

 sides ; venter pale, with diffused black patches toward the 

 posterior borders of the segments. Legs with the femora 

 white below, femora and tibiae lined with white on the inner 

 side only, black without ; tarsi narrowly and often indistinctly 

 ringed with white at both ends of the joints. Wing-scales 

 dark, narrow and hair-like. 



Male. The proboscis has a complete white ring; otherwise 

 the coloration is as in the female. Hypopygium. Side piece 

 curved, conical at tip ; subapical lobe with three rods, a leaf 

 and a stout seta. Clasper smooth, wide at base, the spine 

 appendiculate and shortly subapical. Tenth sternites with 

 strongly spinose tip and curved basal arm, the latter enlarged 

 at end. Mesosome with the inner process membranous and 

 denticulate, central area with four teeth, outer process thumb- 

 shaped. Ninth tergites undeveloped. 



Larva. Head-hairs multiple ; antennas with the basal part 

 with long spines, the notch at the outer third ; lateral comb of 

 the eighth segment of numerous scales in a patch ; air-tube 

 long and slender, slightly tapering on the outer half, about six 

 times as long as wide ; pecten of about 12 teeth on the basal 

 third of the tube ; hairs single, a long single one beyond the 

 pecten and a short double subapical one are preserved, besides 

 two single ones, one out of line just beyond the long hair 

 mentioned, and another much more out of line beyond the 

 middle of the tube. Possibly there should be four hairs in the 

 posterior row instead of two as here described. These hairs 

 are easily broken, the remaining insertions difficult to find. 

 Anal segment broadly ringed by the plate. 



Larvae in a small dirty pool beside the river. 



Types, one male and two females. No. 2392G, U. S. Nat. 

 Mus. ; Kerrville, Texas, August 20, 1920 (H. G. Dyar). 



Allied to stigmatosoma Dyar (=eumimctes D. & K.). 



