196 Marsh — Cyclopidce and Calanidm of Wisconsin. 



It is quite common in the summer and fall months. As I 

 have found it, it has been of a brownish red color, much like 

 D. sanguineus, with purple tipped antennae and caudal setae. 



D. kentuckyensis Chambers, is probably identical with lepto- 

 pus, although the imperfect figures make it impossible to decide 

 with certainty. 



Diaptomus pallidus Herrick. 



Plate III. Figs. 6, 7 and 9. 



1879. D. pallidus, Herrick (18a) p. 91, pi. II, a-d. 



1884. " " « (26) p. 142, pi. Q, fig. 17. 



1889. « " DeGuerne and Richard (32) p. 62, fig. 17. 



A small, slender species. Cephalothorax elongated oval> 

 widest at about the middle ; the last segment is armed with 

 two minute lateral spines. 



The first abdominal segment of the female is as long as the 

 remaining part of the abdomen, and is dilated laterally. The 

 second abdominal segment is shorter than the third. The 

 furcal joints are about twice as long as broad. 



The antennae reach beyond the furca. The right antenna of 

 the male is swollen anterior to the geniculating joint; it bears 

 no appendage on the antepenultimate joint. 



The outer ramus of the fifth foot of the female is two-jointed; 

 the third joint is represented by two blunt spines. The inner 

 ramus is one-jointed, equaling in length the first joint of the 

 outer ramus ; it is armed with a short spine at tip, and two^ 

 larger ones on inner margin of tip ; the inner surface of the 

 tip is covered with short hairs. 



The fifth feet of the male are slender, with the basal joints, 

 nearly equal in length. The first joint of the outer ramus of 

 the right foot is a little shorter than the basal joint. The 

 second joint is nearly twice as long as the first; on its inner 

 margin at about a third of its length is a short spine-like pro- 

 jection, the lateral spine is slender, situated near the outer 

 end of the joint. The terminal hook is falciform, but not with. 



