DESCRIPTIONS OF GENERA AND SPECIES. 273 



spine, which decreases in thickness from its insertion 

 to its point. The first of these points forward, the 

 others are directed first outward and then backward, 

 so that the distal portion is nearly parallel to the side of 

 tl/r abdomen. The only spines on the notogaster are a 

 pair so close together that they generally look like a 

 single large spine in the median line a little behind the 

 centre, and a pair of much smaller spines further 

 forward. There is not any true sternum. The vulva 

 is very large, extending from the level of the insertion 

 of the lower edge of the coxa of the first leg nearly to 

 that of the insertion of the third coxa ; it consists of 

 two large, slightly chitinized labia, somewhat separated 

 posteriorly ; it is entirely surrounded by a chitinous 

 band or ring at some distance from the labia laterally, 

 but almost touching their posterior ends. This 

 chitinous ring is thickest at the sides and thinnest 

 posteriorly. The epimera run from above the first 

 leg, below the second, and between these two legs ; all 

 run radially inward and join the vulval ring. The 

 epimera of the two posterior pairs of legs are free, that 

 of the fourth leg is very small. The anus is large, 

 placed rather far forward, and entirely surrounded by 

 an elliptical chitinous ring. There are two pairs of 

 spines of moderate size near the hinder part of this 

 ring, and a pair of larger spines on the ventral surface 

 of the abdomen further back and more to the side. 

 Legs thin, rather short ; the fourth pair passing the 

 hind margin by about half the length of the tarsi. 



O t/ O 



They diminish gradually in thickness from the proxi- 

 mal to the distal ends. Coxa3 short and rounded, tarsi 

 longer than the two immediately previous joints ; 

 femora, genuals, and tibiae of about equal lengths. 

 Tactile hairs long on the first three pairs of legs, short 

 on the fourth. The other hairs on the legs are more 

 spine-like in character ; they are a pair on the third 

 joint of each leg, those on the two anterior pairs 

 are strongly curved dowmvard and inward and slightly 

 serrated. A strong, somewhat similar, curved spine 

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