700 



BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



times as long as the third; the fifth is a little longer than the fourth. 

 The flagelluni is ooniposed of seven articles. 



The segments of the thorax are siibequal in length. The lateral 

 margins are straight. The epimera are not distinctly separated from 

 the segments. 



The abdomen is abruptly narrower than the thorax. The first two 



Fig. 740.— Brackenridgia cvvernarum (Aftee Ulrich). n, Dorsal view. 6, Second antenna. 



C, Last ABDOMINAL SEGMENT WITH IIROPODS. (/, MaXILLIPEII. (', THORACIC LEG. /, CLAW. (/, ONE 



OF UROPODA. /(, First maxilla, i, Mandibles. 



segments have the lateral parts covered by the seventh thoracic seg- 

 ment. The sixth or terminal segment has the posterior margin 

 rounded. The basal article of the uropoda does not extend beyond 

 the extremity of the last abdominal segment. The inner branch is 

 about half as long as the outer branch. 



The legs are all ambulatory in cliaracter. The seventh pair has the 

 outer distal extremity of the propodus surmounted with a crest of 

 hairs. 



