NO. 1788. -NORTH AMERICAN ERQA8ILID2E— WILSON. 383 



Male. — ^Mouth-parts a little farther back than in the female, labrum 

 more nearly circular in outline. Mandibles similar to those of the 

 female; maxillary hook considerably enlarged, the terminal claw 

 elongate, slender, and strongly curved. First and second maxillae 

 as in the female. 



Maxilliped in the same position as in the female but much larger 

 and not as rudimentary; basal joint inflated and armed with powerful 

 muscles, not fused with the ventral surface of the head and armed 

 with coarse teeth on the inner margin near the proximal end; terminal 

 joint a stout claw, but in a simple curve, its tip shutting against the 

 teeth on the basal joint. 



ARTIFICIAL KEY TO THE GENERA. 



a. Each of the first three free segments as large as the cephalothorax, the four together 



fully fom--fifths of the entire length Tseniacanthus Sumpf, 1871, p. 387. 



a. Each of the first three free segments much smaller than the cephalothorax, the four 



together about half the entire length b. 



b. Maxillipeds little larger than the second maxillae, their terminal joint seta-like, 

 pointing inwards and forwards, and covered with hairs, with one or two 



accessory plumose setae Irodes, new genus, p. 390. 



6. Maxillipeds much larger than the second maxillae, and armed with a curved 



claw, or with smooth spines folded back against the basal joint c. 



c. Mandibles and second maxillae bipartite; maxillary hooks wanting. 



Phagus, new genus, p. 390. 



c. Mandibles and second maxilte simple; maxillary hooks large and often two- 

 jointed Anchistroi /s Brian, 1906, p. 391. 



Of the seven species here included five have air :k}ij been described 

 under other genus names. For such a radical transposition the 

 author feels that a full explanation is demanded / Accordingly the 

 species are taken in chronological order, and the reasons are clearly 

 stated for the changes that have been made. This subfamily closely 

 resembles the Bomolochinse; perhaps the most obvious differences 

 are the presence of a part of tlie first maxillae in the form of prehensile 

 hooks on the ventral surface of the cephalothorax opposite the 

 bases of the second antennae, and the structure and position of the 

 maxillipeds. 



With reference to the latter nothing need be said beyond emphasiz- 

 ing the fact that both structure and position are more nearly normal 

 than in either of the other subfamilies. 



In regard to the former there has been considerable diversity of 

 opinion, and this in connection with a corresponding diversity in the 

 interpretation of the maxillipeds has occasioned the mislocation of 

 four out of the five species. 



The fifth is a case of simple preoccupation which chronologically 

 comes first. 



