142 Illinois State Laboratory of Natural History. 



and without hairs or spines of any description. The second 

 joint of this ramus is about equal in length to the second 

 joint of the peduncle, and bears on its outer margin, close to 

 the tip, the usual stout seta, which is two thirds as long as 

 the joint to which it is attached. The terminal claw is not 

 regularly curved, but is nearly straight for the basal three 

 fourths. The left leg is biramose, the inner ramus straight, 

 slender, extending about to the middle of the second joint of 

 the outer, and armed at its tip. The second joint of this 

 ramus is as long as the first, if measured from the tip of the 

 apical spine. This spine, seen from behind, is stout, conical, 

 rather blunt, and has opposed to it within, projecting from the 

 inner angle of the segment, a stout, curved seta, slightly 

 plumose on its distal half. Between these, but more closely 

 applied to the outer spine, is a hemispherical cushion-like 

 elevation, set with small, short spinules. On the basal half 

 of the inner margin of this terminal segment is also a much 

 larger hemispherical cushion, but with longer and more slen- 

 der hairs, while the terminal half of the inner margin of the 

 segment preceding is also moderately inflated and covered 

 with delicate hairs. 



"The antenna? of the female are 25-jointed, as usual, 

 and reach to the base of the abdomen. The legs of the fifth 

 pair (PL XXVI., Fig. 2) closely resemble those of stagnalis, 

 but have the terminal sette of the inner rami much less devel- 

 oped. This ramus is a little shorter than the basal joint of 

 the outer ramus, and of about half its diameter. It bears at 

 its tip two stout setae equaling the ramus itself in length, plu- 

 mose under a high power, and has, in addition, at its inner 

 tip and on the inner margin adjacent, a patch of delicate 

 hairs and spines. The second joint of the outer ramus is as 

 long as the first, if measured to the tip of its terminal claw! 

 The latter is nearly straight, very slightly recurved. This 

 joint bears a single spine at its outer distal angle, just within 

 which is the rudiment of the third segment of the ramus, which 

 bears two spines similar to the above, the inner of which is the 

 longer, the outer itself being longer than the adjacent spine 

 of the second joint. Adults of both sexes are blood-red 

 throughout except the egg-sac of the female, which is purple. 



