NO. 2063. NORTH AMERICAN PARASITIC C0PEP0D8— WILSON. 619 



3. Arms slender; carapace scarcely widened anteriorly; a wide gap between the tips 



of the second antennae; first antennae with no traces of segmentation. 



lacae Kr0yer, 1863, p. 622. 



4. Genital segment with a jointed process on either side, on the ventral surface at the 



posterior margin sandrae Gadd, 1901 . 



4. No jointed processes; abdomen transversely lunate or hemispherical; maxillipeds 

 projecting beyond anterior margin and not concealed by second maxillae. 



coregoni (Smith), 1874, p. 623. 



4. No jointed processes; abdomen conical and pointed; maxillipeds small and their 



bases completely hidden between the second maxillae 5. 



5. Carapace ovate, much narrowed and well rounded posteriorly; mouth-tube pro- 



jecting considerably aviblopKHs Kellicott, 1880, p. 626. 



5. Carapace trapezoidal, twice as long as wide, almost covering the second antennae; 



mouth- tube not visible dorsally pimelodi Kr0yer, 1863, p. 628. 



5. Carapace trapezoidal, about the same length and width; not covering the second 



antennae; mouth-tube not visible dorsally percarum Nordmann, 1832, p. 629, 



ACHTHERES CORPULENTUS Kellicott. 

 Plate 34, fig. 63. 

 Achtheres corpulentus Kellicott, 1880, p. 54, pi. 1, figs. 1 to 3. 



Host and record of specimens. — Kellicott's specimens were taken 

 from the gills and gill cavity of the lake herring, Leudchthys artedi, 

 hi Buffalo Harbor and Niagara River. The species has also been 

 obtamed as follows: In the gill cavity of the bloater whitefish, 

 Leudchthys prognathus, from Lake Ontario, at Wilson, New York, 

 by R. R. Wright, On the gills of lake herring from Lake Erie, at 

 Dunkirk, New York, July 7, 1894, collected and identified by Cloud 

 Rutter. On gills of lake herring from Lake Michigan, off Milwaukee, 

 and on gills of ki-eye, Leudchthys hoyi, at the same locality, collected 

 by C. H. Stevenson and identified by G. G. Gurley. From gills of 

 bloater whitefish, Whitefish Bay, Lake Michigan, July, 1894, by R. 

 Rathbun. From bloater whitefish, Lake Ontario, at Wilson, New 

 York, August 26, 1894, by G. G. Gurley, From gills of whitefish, 

 Coregonus clupdformis, Lake Erie, at Dunkirk, New York, July 8, 

 1894, collected by Cloud Rutter and identified by G, G. Gurley, 



Specific characters of female. — Head nearly as long and as wide as 

 the body, ovate, with the anterior end very pomted and the posterior 

 end broadly romided; body m dorsal view broadly elliptical, nearly 

 as wide as long, in lateral view hemispherical, with the tip drawn well 

 under, as in the abdomen of certam female spiders. First antemiae 

 apparently two-jointed, the termuial jomt short and tipped with 

 four tmy setae; second antemiae stout and fleshy, reaching to the 

 anterior margin of the head; mandible with seven teeth, the second 

 tooth the longest, the succeeding ones diminishing regularly in size; 

 second maxillae longer than the body, tapermg considerably and 

 much wrinkled; bulla a broad and flat disk. Egg sacks broad at the 

 base, tapering toward the apex, a little longer than the body and 



