230 Proceedings of Indiana Academy of Science. 
THE COPEPOD PARASITES. 
By CHARLES B. WILSON, Professor of Biology, State Normal Schovl, 
Westfield, Mass. 
Three species of Argulus, two of Ergasilus, and one of Achtheres 
were found upon the fish of the lake. The species of Argulus have all 
been described elsewhere (Proc. U.S. Nat. Mus., XXV, pp. 709, 715, 
718). The life history of one species, A. maculosus, was obtained in 
full, and a brief account was published in 1907 (Proc. U.S. Nat. Mus., 
XXXII, p. 416). Of the two species of Ergasilus, one (E. centrarchi- 
darum) has been described by Wright.* This species is common every- 
where on all fishes of the perch family. The other species was new to 
science; it was named L. versicolor, and a full description with figures 
was published in 1911 (Proc. U.S. Nat. Mus., XX XIX, p. 341: pl. 45). 
The single species of Achtheres, A. percarum, has also been described 
by Wright, Nordmann, Kroyer and others, but several details were here 
supplied that had hitherto been lacking. 
The complete life-history was also worked out for both genera; that 
of Achtheres had been partially described before by Claus and Kellicott, 
while not a single detail had ever been published for Ergasilus. 
1. Argulus catostomi Dana & Herrick. 
Found in the gill-cavity of the white sucker, Catostomus commersont. 
The discovery of this species in Indiana, together with those recorded 
from Lake Champlain and the rivers of Massachusetts, Connecticut and 
New York, shows the distribution of this parasite to be identical with 
that of the host it infests. The specimens here obtained and those from 
Lake Champlain include males, the first of that sex to be recorded for 
this species. 
2. Argulus americanus Wilson. 
Found on the outside surface of the Dogfish or Bowfin (Amaia calva). 
This species does not appear to be very common at Lake Maxinkuckee, 
but possibly an examination of a larger number of fish would show a 
different result. This is the first instance of the species having been 
obtained from fish in their native haunts. 
3. Argulus maculosus Wilson. 
Found on the outside surface of the Common Bullhead (Ameiurus 
nebulosus), the Yellow Catfish (Ameiurus natalis), and the Rock Bass 
or Redeye (Ambloplites rupestris). Only two females were found on 
the Redeye; both were full of ripe eggs; evidently they were hunting 
* Proc. Canadian Institute (N. S.), 1, p. 243. 
