Norfli American Centropaf/uhe. 265 



(isltl(i)i(H Marsh, 1). pullidns Ilerrick, or /-'. siciloidc^, J), orc- 

 goneihsis, and J>. inimitiis, Lilljeborg, and sometimes with two 

 or more of these species. It has been found in Illinois, 

 Indiana, Ohio, Minnesota, Michigan, Wisconsin, and also at 

 East Portland, Oregon. 



DOUBTFUL SPECIES. 



Epischura fluviatilis Herrick. 



Epischura jlxviatilis , Herrick. '83a, p. 381, PI. V.. Fig. 10-20. 

 Epischura flvviatilis, Herrirk, "84, p. 133. PI. Q, Fig. 14-16. 

 Episdnir(ifl%Lviatilis, Herrick, "ST, p. 13, PI. 11., Fig. 21-24. 

 EjnschHraJfiiviatiiis, de Guerne et Richard, "891), p. 92, PI. IV., Fig. 



13. 20. 

 Epischura jlxvidtiUs, Forbe.^, "93, p. 254 (foot-note). 

 Epischura jluviatiUs^ Herrick and Turner, "95. p. 83, PI. XHI., P'ig. 



14-1 G. 

 Lamfflipodia [Epischura'] fa viatilis. Schmeil, *9S, p. 183. 



Of small size, body rather slender ; color greenish blue. 

 Cephalothorax imperfectly six-segmented. Abdomen three- 

 segmented,-diflfering in no way from that of iJiaptomns except 

 in the number of furcal setiie. In the male the second abdom- 

 inal segment bears on its left side a peculiar process con- 

 sisting of two parts forming a clasping organ, the inner part 

 of which is about as long as the third segment and armed at 

 the apex with two small spines, the outer part being slender, 

 curved, and about twice as long as the inner. 



Antenna; 2 5 -segmented, extending somewhat beyond the 

 end of the thorax. Eight male antenna geniculate between 

 the 18 and 19tli segments; last six segments not ankylosed, 

 enlarged portion not greatly sw^oUen. 



Swimming legs biramose, the outer ramus consisting of 

 three segments, the inner ramus of one segment. Basal seg- 

 ments of the two legs fused beyond the last. 



Fifth pair of legs of male uniramose, the two basal seg- 

 ments entirely fused. Right fifth leg three-segmented, the 

 first two segments subquadrate and subequal, about three 

 times as long as wide and entirely unarmed. Third segment 

 slightly longer and broader than the second, tapering to a 



