NO. 1900. NEW SPECIES OF PARASITIC C0PEP0D8— WILSON. 241 



First antennae short and slender, only partially visible in dorsal 

 view; second pair stout, the basal joint considerably longer than the 

 terminal claw. First maxillae stout, the terminal joint as tliick as 

 the basal and tipped with three spines, the central one of which is 

 longer and stouter than the other two ; second maxillae with a slender 

 terminal claw. Basal joint of the maxilUpeds much swollen; termi- 

 nal claw conical, shorter than the basal joint, and slightly curved. 



Exopods of the first two pairs of legs wider than the endopods 

 and considerably flattened. First exopod armed with five short and 

 sharply conical spines; second exopod also witJi five spines which are 

 narrow and bluntly pointed. Endopods of both pairs with a stout, 

 pear-shaped basal joint about as long as the exopod, and a stout 

 terminal spine half as long again as the basal joint. Third legs of 

 the usual plicate form, short and stout and projecting at right angles 

 to the body axis. Fourth legs projecting half their length beliind 

 the posterior margin of the dorsal plate; rami flattened and armed 

 posteriorly around their margins with a broad band composed of 

 rows of papillate processes, each of which bears from three to five 

 short and sharp spines. So far as known no armature of this sort 

 has ever been observed on any other species of the genus. Conse- 

 quently this character alone will serve to distinguish the present 

 species, since it is very prominent. 



Color a brownish-yellow without pigment; egg strings dark cinna- 

 mon-brown. 



Total length (including fourth legs), 6 mm. Width of fourth dor- 

 sal plate, 2.15 mm. Length of cephalothorax, 0.9 mm. Width, 0.9 

 mm. Length of egg strings, 8 mm. 



Male. — General body form oblong, two and a half times as long as 

 wide, somewhat widened posteriorly ; cephalothorax nearly circular, a 

 trifle wider than long with the lateral margins flattened ; antennal area 

 very short but projecting well laterally. Free thorax, genital seg- 

 ment, and abdomen well fused, without transverse grooves, but with 

 marginal invaginations indicating the segments; genital segment much 

 narrower than the free thorax ; anal laminae narrow, conical, and un- 

 armed. Mouth-parts and legs like those of the female, with these 

 difi'erences: The second antennae are larger and stouter; the terminal 

 claw of the maxilUpeds is relatively longer and more abruptly curved ; 

 the third legs are directed diagonally backwards; the spiny processes 

 are lacking on the inner margins of the fourth legs. 



Color as in the female, but a little lighter. 



Total length (including fourth legs), 2 mm. Width of cephal- 

 othorax, 0.51 mm. Width of fourth segment, 0.75 mm. 



(lappaceus, burrlike, that is, armed with prickles like a burr, allud- 

 ing to the fourth legs.) 



20441°— Proc.N.M.voI.42— 12 16 



