120 Illinois State Laboratory of Natwral History. 



shorter than remainder of abdomen ; second segment 

 shorter than third ; third segment and furca about 

 equal. Antennas extending beyond end of furca but 

 not to tips of fureal setae. signicauda. 



32 (27). Second segment of outer ramus shorter than preced- 



ing segment. 



33 (34). Last thoracic segment with a large dorsal process, 



armed with two spines, one minute. First abdominal 

 segment longer than remainder of abdomen, with short 

 mucronate process anteriorly, and posteriorly with 

 large triangular process. Second segment of outer 

 ramus straight, hairy ; third segment represented by 

 two spines, the inner about twice as long as the outer. 

 Inner ramus noticeably shorter than first segment of 

 outer ramus, with two long subequal spines at the 

 apex. Antennae barely reaching furca. trybomi. 



34 (33). Last thoracic segment without dorsal process. 



35 (36). First abdominal segment longer than remainder of 



abdomen, dilated, armed with small spine on each side ; 

 second segment very short; third segment shorter 

 than fureal rami. Second segment of outer ramus 

 shorter than the first ; third segment represented by 

 two spines of which the inner is the longer. Inner ramus 

 extending beyond end of first segment of outer ramus, 

 hairy, armed with two smooth subequal spines. An- 

 tennae extending just beyond furca. ashlandi. 



36 (35). First abdominal segment about equal to remainder 



of abdomen. 



37 (38). Second abdominal segment very much shorter than 



the third. Last two thoracic segments confluent ; the 

 last one armed on each side with two small spines. 

 First abdominal segment with large spine on each side ; 

 third segment longer than the second or the furca. 

 Second segment of outer ramus shorter than the first ; 

 third segment represented by two small spines, the 

 inner about twice as long as the outer. Inner ramus 



