DESCBTPTTONS OF GENERA AND SPECIES. 211 



is small. The claw is short, strong, and sharply curved. 

 The abdomen is widest at the anterior margin, and 

 diminishes in width rapidly toward the posterior mar- 

 gin, which is deeply incised in the middle, so as to be 

 almost bifid. It bears on each lateral edge three or 

 four large raised mammilliform tubercles ; the number 

 varies. I most commonly find three ; the posterior of 

 them forms the posterior projecting corner of the 

 abdomen. Megnin draws three besides the projecting 

 corner. Megnin also draws three similar tubercles on 

 the central portion of the notogaster. I have seen 

 these, but I more usually find the notogaster hollow, 

 as in PL II, fig. 3. There is a short curved hair on 

 each antero -lateral corner of the abdomen, one on the 

 posterior tubercle, and two on each lateral margin near 

 together and near to the posterior end. The epimera 

 of the first pair of legs are joined to the sternum; 

 those of the second pair are free, but are large and 

 nearly meet. The third seem broken into two sclerites. 

 The fourth are well marked and of the reversed Y type. 

 The penis is placed posterior to the epimera of the 

 fourth pair of legs. The anus is minute and near the 

 posterior margin. There is a pair of small chitinous 

 rings on the ventral surface just anterior to the penis, 

 and another pair, rather larger and rather further 

 apart, between the anterior ends of the epimera of the 

 fourth pair. There are two or three pairs of very 

 minute spines on the ventral surface. 



Female. This is a larger and wider creature than 

 the male. The posterior portion of the rostrum is 

 more bulbous, and the posterior part of the cephalo- 

 thorax has a convex lateral outline. In consequence 

 of the greater length of the abdomen the fourth pair 

 of legs do not pass its posterior margin ; the abdomen 

 in the specimens I have seen most commonly increases 

 slightly in width from the anterior until near the 

 posterior end. Megnin draws it decreasing slightly ; 

 this, however, is partly a question of age and condition. 

 The epimera of the third pair are similar to those of 



