DESCRIPTIONS OF GENEKA AND SPECIES. 249 



hairs are entirely upon the fine outer layer, or epios- 

 tracum, of the cuticle, which forms a sheath ; this 

 layer occasionally gets detached (see PL VII, fig. 5), 

 and then the tarsus appears quite smooth. There are 

 two or three pectinated hairs on the various joints 

 other than the tarsus of each leg, and the usual tactile 

 hairs. The genual of the third leg bears a broad, 

 flat, lanceolate scale on its outer side, which scale is 

 clothed with short fine hairs, like the tarsi. The 

 epimera of the first pair of legs are joined to the 

 sternum, those of the second pair are free. 



The vulva is long, parallel-sided, rather open, and 

 placed between the second and third pairs of legs ; it 

 is not chitinized, but is protected anteriorly by a semi- 

 lunar sclerite. It has two pairs of very short hairs at 

 the side. The labia of the anus project slightly 

 beyond the posterior margin of the abdomen. There 

 are a pair of short hairs at the anterior end. 



Male practically similar to the female, but somewhat 

 smaller, and, of course, without the projecting bursa 

 copulatrix. The penis is placed almost between, but a 

 trifle anterior to, the coxae of the third pair of legs ; 

 there are a pair of short hairs at the sides of it, and 

 another posterior to it. The hairs on the body are 

 longer in proportion to the body itself than those of the 

 female. 



The Nymph and Larva closely resemble the adults, 

 with the ordinary exceptions. 



The Hypopial Nymph (PL VIII, fig. 17). Only 

 slightly developed, and rarely emerging from the hypo- 

 pial case. It is not really functional, but still is 

 capable of individual movement when removed from 

 the case. In order to avoid repetition the reader is 

 referred to page 170 for information on this point. 

 The hypopial case in this species (PL VIII, fig. 11) is 

 covered with fine reticulations (PL VIII, fig. 15), and 

 opens posteriorly bv the splitting of that end of the 

 case (PL VIII, fig. 13). 



