46 Illinois State Laboratory of Natural History. 



posterior margins of all but the last segment are irregularly 

 and often very obscurely serrate. The last segment is 

 bordered posteriorly by the usual row of spinules. The sty- 

 lets are often slightly outcurved. In relative length to breadth 

 they vary from four to one to nine to one, but the usual 

 proportion is as seven to one. The inner of the two longer 

 seta; is as long as the entire abdomen, and the outer of the 

 two but half that length. The extreme outermost of the 

 terminal setae is two thirds as long as the inner. On the 

 outer side of each stylet, a little behind the middle, is 

 placed a spine surrounded at its base by a ring of spinules, 

 and at one fourth of the distance from the proximal end is a 

 vertical comb of small spines (PI. XII., Fig. 2). This 

 character seems to be invariably present. 



The antennae of the female are moderately robust and 

 terminate in the American forms between the posterior end 

 of the first segment and the middle of the third segment. 

 A sense-club is borne on the distal end of the twelfth segment. 

 No hyaline plate is present on the terminal segments. The 

 last three segments gradually increase in length toward the 

 distal end of the antenna, the antepenult being two fifths 

 the length of the last. The two segments preceding the 

 former, taken together, are shorter than the last segment, 

 and about equal to the penultimate. 



The armature of the thoracic legs is as follows : — First pair : 

 outer ramus, two spines, four seta ; inner ramus, one seta, 

 one spine, four seta. Second pair : outer ramus, three spines, 

 four seta ; inner ramus, one seta, one spine, four seta. 

 Third pair, exactly like second. Fourth pair : outer ramus, 

 three spines, four seta; inner ramus, one seta, two spines, 

 two seta. 



The fifth pair (PI. XII., Fig. 3) are two-segmented, the 

 basal segment about as long as broad, with a plumose seta at 

 the outer angle, the terminal segment roughly cylindrical, at 

 least twice as long as broad, with two terminal seta-, the outer 

 of which is as long as the seta of the preceding segment and 

 the inner a little more than half that length. This inner seta 

 is sometimes spine-like. 



