CHAMBERLIN: HENICOPIDAE OF AMERICA NORTH OF MEXICO. 19 



Outer branch of first maxillae rather indistinctly triarticulate; its 

 ultimate article clothed on mesal surface with plumose bristles and 

 bearing at anterior end a much larger laciniate bristle (see Plate 3, 

 figs. 2 and 4). Inner branch small, discrete from coxa, clothed with 

 simple bristles of which one at apex is upon a much broader base 

 and is stouter than the others (see fig. 2). 



Eyes absent. 



Antennae of medium length or long. First two articles long, the 

 immediately succeeding ten or eleven greatly shortened, with those 

 more distad longer. Articles so far as known, 36 to 45. 



Prosternum with the anterior margin wide, not narrowly produced 

 as in Lamyctes; teeth small, mostly 3+3. 



Six pairs of spiracles present, none occurring on the first leg-bearing 

 segment. 



None of dorsal plates, so far as known, with posterior angles pro- 

 duced. 



First twelve or thirteen^pairs of legs with an acutely pointed tibial 

 process or spur; the tarsi of these legs only indistinctly or not at all 

 divided, the suture not affecting the dorsal side of article, but in part 

 detectable on ventral side. (Plate 3, fig. 9). 



Coxal pores present on last four pairs of legs; por.es few, uniseriate 

 and small. 



Both males and females occurring commonly under the same condi- 

 tions. 



TYPE. B. oabitus Chamberlin. 



In the known species the body is more slender than in Lamyctes 

 and the legs are relatively longer. The coloration is light throughout, 

 yellow and pale orange with no darker pigment occurring. 



In addition to the type species one other is at present known. The 

 two species may be discriminated as follows: 



Key to species. 



a. Antennae composed of 36 articles; more than half as long as the 

 body. B. oabitus Chamberlin. 



aa. Antennae composed of 43-45 articles; nearly always clearly 

 less than half as long as the body. B. coniugans Chamberlin. 



