222 ]ouKNAL New York Entomological Society. [Voi x. 



2-6; heavy, blacki.shhrovvn, median transverse bands in segments i-S, much paler, 

 however, in segments i and 2 ; all darker along the posterior portion and separated by 

 a clear transverse band in the posterior portion of the segments ; a narrow, clear, 

 median stripe separates them longitudinally, except in the eighth segment ; ninth 

 segment small, rounded and slightly emarginate at the tip. 



Legs short and stout, especially the femora ; darker than the body, being the 

 same color as the head with darker annulations and semi-annulations on the temora 

 and tibia'. 



Numerous females collected from specimens of the Western Lark 

 Sparrow ( Cliondestes i:^raininaci/s sfn'x^afus), in the IJttle Bad Lands, 

 Sioux Co., Neb., June 17, 1901. 



I'his form seems to have little resemblance to any species hitherto 

 described, and is easily recognized by the long, narrow, dusky head, 

 the absence of lateral abdominal bands and the heavy, median, trans- 

 verse, abdominal bands. 



Nirmus trimarginis, sp. nov. (PI. XX, Fig. 2; PI. XXI, Fig. 5.) 



J-'ciiuih:. — Body, length 1. 87 mm., width .61 mm.; head triangular, front nar- 

 rowly truncate ; prothorax short, quadrangular ; rnetathorax short, with widely 

 diverging sides; abdomen almost a perfect oval, narrowly margined with deep chest- 

 nut. 



Head, length .5 mm., width .5 mm.; triangular, slightly swollen at trabecul?e ; 

 front sharply conical, with sides straight and clypeus squarely truncate ; two short hairs 

 just behind the lateral angles of the clypeus, one at the suture and one in front of the 

 trabecule ; trabeculse slender, clear, bluntly pointed, and equal to the first segment of 

 the antenna; ; antenna; rather short and slender, first segment thickest, second longest, 

 nearly as long as the last three combined, which are uniformly darker; eye small, 

 scarcely perceptible, obscured by a blotch and furnished with a long stout hair ; temples 

 rounded, with two long hairs in large pustules, and several short bristles ; occipital 

 margin concave with the occiput slightly convex ; the chestnut antennal bands nar- 

 row, broken at the suture and extending nearly to the lateral angles of the clear 

 clypeus, while the posterior portion, bending angularly inward at the trabecular, 

 passes backward to, and joins at the middle portion, the somewhat broken occipital 

 bands ; temples narrowly edged laterally with deep chestnut. 



Prothorax short, quadrilateral, narrower in front, with the anterior angles flatly 

 rounded and the sides nearly straight, but slightly diverging ; posterior angles rounded, 

 with one long hair ; whole segment rather indistinctly margined with dull chestnut, 

 while the coxal lines are large and plainly visible. Metathorax scarcely longer than 

 prothorax, sides rounded and widely diverging ; posterior margin angulated with 

 several pustulated hairs on each side ; a dark blotch at the anterior angles, and a 

 broad band along the lateral margins, extending inward from the posterior angles. 



Abdomen an almost perfect oval, slightly pointed posteriorly, widest at fourth 

 and fifth segments ; posterior angles projecting, with one hair, except on the first, 

 -eighth and ninth segments which have none ; segments two to seven sharply and 

 narrowly margined with deep, blackish chestnut, projecting into the adjacent anterior 



