CHAMBERLIN: HENICOPIDAE OF AMERICA NORTH OF MEXICO. 27 



nent; more loosely joined and relatively longer articles of 

 antennae beginning with the seventeenth. 

 Body eight times as long as width of tenth plate. 



Z. sokarienus Chamberlin. 



aa. All legs with well-developed tibial processes; posterior angles 

 of sixth, seventh, ninth, eleventh, and thirteenth dorsal plates 

 produced. Zantethobius Chamb. 



Articles of antennae 43; body seven times longer than width of 

 tenth *dorsal plate. Z. pontis Chamberlin. 



ZYGETHOBIUS DOLICHOPUS Chamberlin. 



Henicops dolichopus Chamberlin, Proc. U. S. N. M., 1901, 24, p. 797. 



Henicops- fulvicornis Chamberlin, (in part), Proc. U. S. N M., 

 1901, 24, p. 25. 



Zygethobius dolichopus Chamberlin, Ent. news, 1903, 14, p. 335. 



Zygethobius dolichopus Chamberlin, Pomona college journ. ent., 

 1910, 2, p. 368. 



DIAGNOSIS. Dorsum yellowish brown to dark brown, with first 

 and last plates commonly darker and more reddish; head darker, 

 often chestnut to nearly black with median and posterior portions 

 paler; legs yellow to brown, more reddish distad, the posterior pairs 

 darkest; the whole often suffused with violaceous. Head subrotund, 

 longer than wide. Body strongly narrowed cephalad from tenth 

 dorsal plate and more abruptly caudad ; eight times longer than width 

 of tenth plate. Antennae long; articles 39 or 40; articles distad of 

 the fourteenth more loosely joined and showing an alternation of 

 shorter ones in pairs with single longer ones, but the last six all long. 

 Prosternal teeth, 3+3, small, the two innermost on each side closer 

 together. Posterior angles of ninth, eleventh, and thirteenth dorsal 

 plates produced. Coxal pores 3, 3, 3, 3-3, 4, 5, 5, 4, circular. Legs all 

 long, especially the caudal pairs ; tibial process present on legs of first 

 fourteen pairs. Claw of female gonopods large, not strongly curved: 

 basal spines 2+2 or 2+3; conical in outline, dorsally excised distad, 

 with plane of inner nearly at right angles to outer. Length 11.4-12.6. 



DESCRIPTION. Color of dorsum yellowish brown to dark brown, 

 first and last plates darker, sometimes reddish brown. Head fre- 

 quently very dark, its anterior and lateral portions reddish, at times 

 verging to black with the middle and posterior portions paler. An- 

 tennae yellow to brown, reddish brown or chestnut at base. Ventral 

 plates smoky yellow. Legs mostly yellow, brown or somewhat red- 



