66 ILLINOIS BIOLOGICAL MONOGRAPHS [66 



Dr. H. B. Ward from Esox reticulatus Le Sueur (type host) ; Sebago 

 Lake, Maine (type locality). 



Co-type: Alcoholics No. TLH413 in Dr. H. B. Ward's collection, 

 from Esox lucius Linn., Walnut Lake, Michigan, and slides of the same. 



Autotype : Alcoholics No. 10.35 in collection Dr. H. B. Ward from 

 Esox lucius Linn., Lake Geneva, Wisconsin. 



Leidy (1888:169 and 1890:417) described some specimens of ces- 

 todes from Esox reticulatus. The two specific names which he proposed 

 for them the writer considers to be synonyms and has included under 

 the one name, Proteocephalus nematosoma (Leidy). Leidy 's specimens 

 were considerably larger than the specimens of P. pinguis and appar- 

 ently are not the same. A more complete discussion of Leidy 's species 

 occurs later in the article. La Rue (1911:478) briefly characterized 

 this species and proposed for it the name Proteocephalus pinguis. 



This study is based, for the most part, upon specimens collected by 

 Dr. H. B. Ward from the intestines of Esox reticulatus Le Sueur at 

 Sebago Lake, Maine, while engaged in an investigation of that lake for 

 the U. S. Bureau of Fisheries, in the summer of 1907. Portions of the 

 study are also based upon specimens secured by Prof. T. L. Hankinson 

 from Esox lucius Linn, in the course of a biological investigation of 

 Walnut Lake, Mich., during the summer of 1906. This last material 

 was referred to in a former paper, La Rue (1909:25), as "A new spe- 

 cies, which I shall describe in detail later ". It bears the number 



TLH413 in Professor Ward's collection. Dr. H. B. Ward examined six 

 specimens of Esox reticulatus Le Sueur while at Sebago Lake. These 

 six fish yielded sixteen entire Proteocephalids and pieces as follows: 

 No. 4, 1 head+2 pieces; No. 6, 2 heads+2-3 pieces; No. 7, 1 head+2 

 pieces; No. 8, 11 heads-}- 2 pieces; No. 9, 1 head; No. 107, 5 heads, 1 

 young cestode-|-10 large pieces. In many instances the specimens re- 

 ported as heads were complete worms while in others the end proglottid 

 and part of the strobila were missing. Thus the infection of Sebago 

 Lake hosts was light. Hankinson 's material in bottle No. 413 from 

 Esox lucius of Walnut Lake was probably from a single host. It con- 

 tained 60-70 specimens of P. pinguis. A bottle, No. 10.35 in Dr. H. B. 

 Ward's collection, bearing the label "from stomach and intestine of a 

 'pickerel,' Lake Geneva, Wisconsin, Jy. 1, 1904. A. J. Coats, collector", 

 contained 5 or 6 complete specimens of P. pinguis La Rue and several 

 pieces of the same species. Replying to a letter of inquiry Prof. George 

 Wagner of the University of Wisconsin states that only one species of 

 pickerel, the Esox lucius, is found in Lake Geneva, Wisconsin. The data 

 on this species were obtained from specimens cleared and examined in 



