NO. 1788. NORTH AMERICAN EROASILIDM— WILSON. 341 



Total length of female, 0.9 mm. 



(Jizsd, from liza, the specific name which Kroyer gave to the mullet 

 on which this parasite was found.) 



A few specimens of this species were taken with other parasites from 

 the gills of Mugil curema (M. liza Kroyer), captured near New Orleans, 

 Louisiana. As in the case of Ergasilus funduli, Kroyer obtained these 

 parasites from the gills of fish which had been sent to the Royal 

 Museum in Copenhagen, and no further specimens have ever been 

 seen. But here again it is also true that no mullet from that region 

 have ever been examined for parasites since Kroyer's time. And it 

 is possible that a little search would show the species to be fairly 

 common. 



ERGASILUS VERSICOLOR, new species. 

 Plate 45, text figures 11 and 12. 



Female. — Carapace elliptical, three-fourths longer than wide and 

 violin-shaped, the part in front of the lateral constrictions longer 

 than that behind them. Anterior margin narrowed and projecting 

 strongly between the antennae; posterior margin somewhat emar- 

 ginate. First three free segments about the same length but dimin- 

 ishing regularly in width, the fourth a little narrower than the third 

 and not more than a quarter as long. Fourth (third free) segment 

 posteriorly and genital segment anteriorly contracted into a short 

 neck where they join the short fifth segment. Abdomen indistinctly 

 three-jointed, joints about the same length; anal laminae small, a 

 trifle longer than the last abdomen segment, quadrangular in outline 

 and slightly divergent, each armed with two unequal setae. 



First antennae six-jointed, the second joint the largest, the fourth 

 joint next in length, and all heavily armed with setae. Second antennae 

 long and slender, three-jointed, the basal joint less than half the length 

 of the second, the terminal joint a stout claw, a little longer than the 

 second joint, but bent into a half circle so as to appear shorter. 



Labrum not reaching the base of the first maxillae; mandibles rela- 

 tively large, the cutting blades curved forward and outward nearly 

 in a half circle, and fringed along the margins with a dense row of 

 stout spines. Palps short and triangular, with a few short and sharp 

 teeth at the apex and a row of rounded teeth along the outer margin. 



Basal portion of the first maxillae in the form of an elliptical papilla, 

 tipped with two stout spines of which the outer is a little larger than 

 the inner. Second maxillae with a peculiarly stout terminal joint, the 

 two appendages overlapping somewhat at the mid-line, and each 

 armed with a small tuft of bristles, restricted to the center of the 

 distal end. Labium distinctly U-shaped, its ends running forward 

 under the first maxillipeds almost to the base of the mandibles. 



