CHAMBERLIN: HENICOPIDAE OF AMERICA NORTH OF MEXICO. 25 



Anal glands well developed. 



Sternite of genital segment bearing on each side three bristles. 

 First article of female gonopods with three bristles, second with two 

 or three and the ultimate with two of which one is long and one short. 

 Claw pale and thin, weak. Basal spines all present, but short and 

 pale with the inner one of each pair more slender and much shorter 

 than the outer, extending scarcely distad of the middle of the latter. 



Length 6.75 mm. 



LOCALITIES: California (Berkeley! Mill Valley!). 



ZYGETHOBIUS Chamberlin. 

 Ent. news, 1903, 14, p. 335. 



Labrum mesally deeply incised and unidentate as in other genera 

 of the family; tooth acutely conical and strongly chitinized; lateral 

 divisions not at all notched at median excavation. Lateral portions 

 with a fringe of plumose hairs along margin much as in Buethobius, 

 some of which also occur on caudal portion of dorsal surface which 

 also bears more cephalad an area of simple hairs (see Plate 5, fig. 2). 



In the mandibles at distal end and beginning at cephaloventral end 

 of dentate plate are, first, three pairs of stout, obliquely placed teeth 

 followed next to caudal angle by a fourth pair consisting of one large 

 tooth and a much smaller one. Pectinate aciculi and plumose hairs 

 nearly as in Buethobius but the aciculi fewer, being mostly about 6 

 in number (see Plate 5, fig. 5). 



Both branches of the first maxillae separated from the coxae. Inner 

 branch armed with simple hairs and hairs that are laciniate at distal 

 end, the latter showing two, three, and more branches, but no truly 

 ramose or plumose hairs are present. Outer branch clearly triarticu- 

 late; the ultimate article bearing plumose hairs on mesal surface; 

 no branched aciculi at anterior end. (Plate 5, figs. 3 and 4). 



Eyes present, each consisting of a single large ocellus which is larger 

 than that in Lamyctes and is situated farther forward. 



Antennae long; in known species consisting of from 38 to 43 articles. 



Prosternum with anterior margin wide and not much extended 

 forward; teeth 3+3. (Plate 4, fig. 6). 



Only six pairs of spiracles present, none being found on first leg- 

 bearing segment. 



Posterior angles of ninth, eleventh, and thirteenth, or of these with 

 seventh, or of these with both sixth and seventh, strongly produced. 



