CHAMBERLIN: HENICOPIDAE OF AMERICA NORTH OF MEXICO. 31 



narrowed cephalad. Antennae long; articles 38 or 39; articles distad 

 of the sixteenth relatively more slender and more loosely articulated, 

 with shorter ones in pairs alternating with longer single ones but last 

 six all of longer type. Prosternum with anterior margin widely 

 rounding as usual; teeth 3+3. Posterior angles of niath, eleventh, 

 and thirteenth dorsal plates produced. Coxal pores 2, 3, 3, 3, 3-3, 4, 

 4, 4, 4: circular and small. Legs long; tibial spur occurring on each 

 leg of the first, fourteen pairs. Claw of female gonopods long and 

 acute, moderately curved; basal spines 2+2, distally thin, conical 

 in broader outline, with the inner set at an angle with the outer. 

 Gonopods of male long; ending in an acutely pointed and bristle- 

 tipped process or claw of which the ventral edge is serrate. Length 

 11-13 mm. 



DESCRIPTION. Dorsum reddish brown or chestnut, with the ulti- 

 mate segments darker. Head darker than dorsum, uniform. Anten- 

 nae dark reddish brown proximally, becoming pale distad. Venter 

 from light to dark brown, often of reddish tinge, the posterior segments 

 usually darker. Prosternum usually of same color as venter but some- 

 times darker, in which case the prehensors are paler, especially distally. 

 Legs usually brown, sometimes dark excepting proximally and 

 distally; the posterior pairs, as usual, commonly darker than the 

 others. 



Body moderate; about eight times longer than width of tenth plate; 

 conspicuously narrowed from tenth plate cephalad and abruptly 

 cauclad. Sparsely clothed with shorter, finer hairs and with longer 

 coarse spinescent bristles, the latter being more especially arranged 

 in series at lateral and caudal edges of dorsal plates and also across 

 anterior portion of major ones. The bristles more abundant on legs. 

 Antennae densely clothed with straight hairs of which there are short 

 and moderately long ones, the latter becoming reduced from proximal 

 to distal articles. 



Head normally longer than w r ide (12:11, nearly); subrotund, but 

 sides not so strongly convexly bulging as in dolichopus; widest in 

 front of middle, from where the sides caudad are substraight or a little 

 incurved to the rounded caudal corners; caudal margin straight; 

 head narrowed cephalad as in dolichopus. Head convexly elevated. 

 Conspicuously constricted or furrowed in a semicircle curving caudad 

 from the ocelli; two furrows on caudal portion of plate diverging 

 forward from a common point and on each side of these are several 

 subparallel sulci; a shallow median longitudinal furrow extending 

 caudad between antennae to the transverse furrow. (Plate 4, fig. 5). 



