626 PROCEEDINGS OF THE NATIONAL MUSEUM. tol. 47. 



ACHTHERES AMBLOPLITIS Kellicott. 

 Plate 25, fig. A; plate 36, figs. 81 to 85; plate 37, figs. 86 to 91. 

 AcMhcrcs amblopUh's Kellicott, 1880, p. 56, pi. 3, fig^. 6 and 7. 



Host and record of specimens. — Three lots of this parasite were 

 obtained from the gills of the red-eye, AmUoplites rupestris, at Lake 

 Maxinkuckee, Indiana, and are numbered respectively 39614, 39615, 

 and 43570, U.S.N.M. The firet lot includes 5 females with egg strings, 

 the second lot 15 females, and the third lot 100 specimens of both 

 sexes. Since Kellicott's types have been lost, this last lot will sei-ve 

 as surrogate types of the species. Fifteen females were taken from the 

 gills of "Redfish" at Big Payette Ijake, Lardo, Idaho, and are num- 

 bered 39624, U.S.N.M. Gurley records the species as occurring on 

 fully 50 of the red-eyes taken in the Shiawassee River, Michigan, a 

 tributary of Lake Huron. 



Specific characters of female. — Cephalothorax much smaller than 

 the trunk, the separatmg groove being narrow and deep; ovate in 

 outline, with a fairly well defined carapace. This carapace is wide 

 and roundly truncated anteriorly, while the cephalothorax itself is 

 just tlio reverse. It follows that where the two intersect on the lateral 

 margins there is a shallow notch. 



Trunk broadly ovate or somewhat spindle-shaped, narrowed to a 

 short but distuict neck where it joins the cephalothorax, and tapering 

 posteriorly to a bluntly rounded point, the abdomen. 



Egg strings arising from the dorsal or dorso-lateral surface and 

 strongly divergent, largest at the base and tapermg toward the tips; 

 eggs large, in 3 or 4 longitudinal rows, 8 or 10 eggs in each row. 

 The genital segment between and behind the egg strings is strongly 

 narrowed and to its posterior margin is attached the short and 

 conical abdomen. Two spherical spermatophores, wine red in color, 

 are often found attached to this abdomen, occupymg the position 

 usually filled by the anal laminae. 



First antennae indistinctly three-jointed, long and slender, and 

 tipped with three small setae; second antennae biramose, endopod 

 bluntly rounded, one-jointed, and armed with tiny spines; the 

 exopod two-jointed, narrower than the endopod, tapermg quite 

 rapidly, and armed at the tip with a single stout spine curved like 

 a claw. 



Mandible broad and stout, with six large primary teeth and a 

 single secondary one; first maxillae consisting of a single joint, short, 

 narrow, and bipartite at the tip; second maxiOae large and stout, 

 and in the mature adult profusely wrinkled; bulla funnel-shaped; 

 maxillipeds with a rather stout basal joint, and a short but stout 

 terminal claw, reenforced on the mner margin near the tip with a 

 single spmc. 



