1903.] NATURAL SCIENCES OF PHILADELPHIA. 159 



spines 1, 3, 3, 1; anal legs with the claw unarmed, spines 1, 3, 2, 0, in 

 the d^ much modified, enlarged, the tibia above at the distal end pro- 

 duced into a large knotty lobe, the lobe truncated posteriorly, sparsely 

 pilose, bearing upon its posterior surface a spine which projects cau- 

 dally; the last 2 pairs of coxse armed laterally, the last 3 dorsally. 

 Coxal pores very small, 2, 3, 3, 2 



Length of body 8.8 mm.; width of 8th dorsal plate 1.3 mm. ; length 

 of antennae 3 mm. ; length of anal legs 3 mm. 



Habitat. — Shasta Springs, Cal. 



Etymology. — Latin castellum, a citadel or fortified place, and pes, 

 foot, a name suggested by the appearance of the enlargement on the 

 tibia of the c? anal legs. 



10. Lithobius clavigerens sp. nov. 



Description. — Color of body, antennae and last pair of legs brown, 

 other legs yellowish; head and dorsum smooth and glabrous, the head 

 sparsely minutely pimctate; ventral plates and the prosternum with 

 prehensorial feet smooth, sparsely pilose, the last 2 together with the 

 genital and anal segments subdensely pilose ; antennae pilose, the outer 

 surface of the proximal articles subglabrous. Head sub-round, about 

 equal in length and width, narrowed anteriorly. Antennae: articles 

 20, the ultimate about equaling in length the 2 preceding taken to- 

 gether. Ocelli: 10-14, pale and distinct, in 3 series (1+5, 5, 3). Pro- 

 sternal teeth 2-2, moderately small. Spines of the first legs 1, 3, 2, 

 penult legs with 1 accessory claw, spines 1, 3, 3, 1; anal legs with the 

 claw unarmed, spines 1, 3, 2, 0. Anal legs in 9 scarcely more slender 

 than in d" ; the exterior and interior superior margins of tibial and 

 tarsal joints extended laterally, making the upper surface flat, the 

 femur compressed in a different plane; the tibia densely punctate 

 beneath, the tarsal joints less densely so; the first tarsal joint with a 

 knob-like swelling at proximal end (absent incJ^); penult legs similarly 

 modified to anal and to a scarcely smaller degree. In thed^ the anal 

 legs are also swollen along or a httle below the superior margins, but 

 the expanded portions are thicker and not so suggestive of flattening ; 

 tibia marked above for its entire length by a ridge-like swelHng which 

 at the proximal end is produced upward and inward into a conspicuous 

 pilose lobe, tibia sparsely punctate beneath, the tarsal joints more 

 densely so ; in the penult legs the tibia is somewhat similarly modified 

 to that of the anal legs, but the lobe at the proximal end is missing 

 not so strongly modified as in 9 . Coxal pores small and round, 

 3, 4, 4, 3. Gonopods of 2 : claw rather large, tripartite, lobes all acute, 



