234 The Ruffed Grouse 



known to infect a number of other birds elsewhere in the Western 

 Hemisphere. 



The Cestodes (Tapeworms). At least seven species of tapeworms 

 have been found in the ruffed grouse. Since many of these found in 

 autopsies made in the course of the New York study have been listed 

 in published ' records only by genus or simply as "cecal cestoda" or 

 "tapeworms," it has not been possible to analyze accurately the oc- 

 ciurence of the different species in each genus found in New York. 



Hyinenolepis microps (Diesing) 



Hymenolepis carioca (Magalhaes, 1898) (?) 



Hymenolepis sp. 



Specimens of this genus of tapeworms have been reported from 

 New England (New Hampshire), New York, Minnesota, and On- 

 tario. They are found in the small intestine, primarily in the duo- 

 denum. 



This is the only genus of tapeworms identified in the reports of 

 the New York study. Only a portion of the tapeworms reported were 

 determined as Hymenolepis sp. but it seems lil^ely that at least the 

 majority of those identified as "intestinal cestoda," or merely "tape- 

 worms," were of this group. 



The prevalence of these intestinal tapeworms in adult grouse 

 varied greatly in different years, the incidence varying from zero 

 to twenty-three per cent, with no clear-cut trends. The average in- 

 cidence was seven per cent; but none at all were found in four years 

 out of eleven. 



The record is quite different with the chicks in which these para- 

 sites were found every year and in consistently higher proportions. 

 The incidence of infection averaged nineteen per cent over a nine- 

 year period, 1933-41, with extremes of thirty-seven per cent in 1933 

 (based on only eight specimens, however), thirt)'-two per cent in 

 1934, and ten and eleven per cent respectively in 1938 and 1939. 

 The records indicate a consistency of occurrence not usual with 

 grouse parasites. It is notable that the greatest incidence occurred 

 in a period when most parasites of grouse were at a low ebb. 



Clarke (1936) found nine cases of H. microps in Ontario grouse, 

 eight of which were in young birds and one from an adult. All of 



1 N. Y. S. Cons. Dept. Ann. Rep., 1932-42. 



