126 CALIFORNIA ACADEMY OF SCIENCES. 



smaller and with waist-like narrow basal abdominal seg- 

 ments. 



Head, length .53 mm., width .41 mm.; temporal mar- 

 gins with live very short stiff hairs or prickles and one 

 longer hair; antennal bands most strongly marked at 

 anterior end, ocular blotch dark brown, and temporal 

 margin broadly banded with brown paling internally. 

 Lateral bands of prothorax darkest at posterior angles. 

 Metathorax with large, lateral, marginal, dark brown blotch 

 in front of the middle, and margin behind the blotch dark 

 brown ; hairs seven, as in squalidus. Legs concolorous with 

 body, tarsi and claws darker. First two abdominal seg- 

 ments much narrower than succeeding ones, segments 4-5 

 the widest; segments 3-6 with two hairs, a long one and a 

 short one, at posterior angles; segment 9 feebly emar- 

 ginated, thus obtusely two-pointed; segment 1 short, seg- 

 ments 2—3 longest and equal, segments 4—5 next long- 

 est and equal, segment 6 very short especially in middle, 

 segments 7-8 equal; lateral marginal bands distinct, dark 

 brown; within pale yellowish brown quadrangular blotches 

 separated by uncolored median line on segments 2-4. 



The female is larger; body, length 3.12 mm., width 

 .66 mm.; head, length, .63 mm., width .5 mm.; first ab- 

 dominal segments shorter, segments 2-7 about equal, 

 segment 9 very slightly emarginated. 



The young of this species, as probably of all bisetosi, 

 show characteristic transparent, narrow, lateral, abdominal 

 margins, and on segments 1-7 along the lateral third of 

 the hinder margin of each segment a linear transparent 

 space; no brown markings. 



Lipcurus ftnicl ulatiis of Rudow (Zeitsch. f. ges. Natur 

 wiss., v. xxxvi, p. 137), from Oidemia fusca is probably 

 an immature specimen of this species. 



