NORTH AMERICAN PARASITIC COPEPODS. DESCRIP- 

 TIONS OF NEW GENERA AND SPECIES. 



By Charles Branch V/ilson. 



Department of Biology, State Normal School, Westjield, Massachmetts . 



This eleventh paper" in the series cleahng with the North American 

 Parasitic Copepods includes four new species, two of which are made 

 the types of new genera. Two of the species were sent to the author 

 by Dr. Barton W. Evermann of the U. S. Bureau of Fisheries, one was 

 collected by Dr. Edwin Linton at the Tortugas, Florida, and the 

 fourth was found in the Museum of the Johns Hopldns University. 

 Sincere thanks are hereby returned to each of the senders, not merely 

 for these favors but also for many others similarly conferred. 



MIDIAS,* new genus. 



General form intermediate between that of Caligus and EurypJiorns. 

 First three thorax segments united with the head to form the cara- 

 pace; frontal plates poorly defined but furnished with lunules. Fourth 

 or free thoracic segment short and wide, with a pair of very rudi- 

 mentary dorsal plates in the female. 



Genital segment greatly enlarged and carrying a pair of rudimentary 

 legs at the posterior corners in both sexes. Abdomen long, distinctly 



«The ten preceding papers are : 1. The Argulidae, Proc. U. S. Nat. Mus., vol. 25, 

 pp. 635-742, pla. 8-27. 2. Descriptions of Argulidee, idem, vol. 27, pp. 627-655, 38 

 text figures. 3. The Caliginae, idem, vol. 28, pp. 479-672, pis. 5-29. 4. The Trebinte 

 and Euryphorinpe, idem, vol. 31, pp. 669-720, pis. 15-20. 5. Additional Notes on the 

 Argulidje, idem, vol. 32, pp. 411-424, pis. 29-32. 6. The Pandarinae and Cecropinae, 

 idem, vol. 33, pp. 323-490, pis. 17-43. 7. New Species of Caliginae, idem, vol. 33, 

 pp. 593-627, pis. 49-56. 8. Parasitic Copepods from the Pacific Coast, idem, vol. 35, 

 pp. 431-481, pis. 66-83. 9. Development of Achtheres ambloplitis Kellicott, idem, 

 vol. 39, pp. 189-226, pis. 29-36. 10. The Ergasilidse, idem, vol. 39, pp. 263-400, pis. 

 41-60. 



6 Midias, a disreputable Athenian. 



Proceedinqs U. S. National Museum, Vol. 39, No. 1805. 

 Proc. N.M. vol. 39— 10 42 625 



