The Diseases and Parasites of Wild Ruffed Grouse 233 



yellowish in color, measuring about two millimeters long. The num- 

 ber found in an individual varied from one to many dozens." Only 

 the larvae were found, and the primary host is not known. 



Boughton found them present in three and twenty-five hundredths 

 per cent of the birds examined from Minnesota. However, their 

 presence was not considered serious to the birds for, when com- 

 paring grouse weights to analyze the effects of parasitism, those 

 having only Physaloptera larvae ". . . were considered uninfected." 



These parasites have not been reported in grouse farther east than 

 Wisconsin. 



Tetrameres americana ( Cram, 1927 ) . This parasite is found in the 

 stomach ( proventriculus ) . It was first reported from ruffed grouse 

 by the New York study in 1936 (N. Y. S. Cons. Dept. Ann. Rep., 

 1936) although common in poultry in the South. In 1937, it had ap- 

 parently increased somewhat in prevalence, being found in about 

 nine per cent of the adult birds examined. Thereafter its occurrence 

 fell off. "Of just what significance this parasite is to game birds is 

 unknown, but since it is a great destroyer of tissue and causes heavy 

 losses among poultry in the South and has been found in pheasants 

 and Hungarian partridge also, it is possible it may become impor- 

 tant" (N. Y. S. Cons. Dept. Ann. Rep., 1937). 



Other Nematodes. Three other species of nematode worms have 

 been found in ruffed grouse in the northeastern quarter of the United 

 States and eastern Canada. None is common or of much ecological 

 significance so far as known. 



The gapeworm Syngamus trachealis, Montagu (1811), was re- 

 ported in six adult grouse out of six hundred and sixty-two examined 

 during the New York study from 1932 to 1935, none thereafter; and 

 in seven young grouse out of six hundred and eighty-three specimens 

 between 1933 and 1939, none thereafter. As the name implies this 

 parasite infects the bird's windpipe, causing it to "gape" or choke 

 in an effort to get rid of the cause of irritation. 



Allen and Gross ( 1926 ) report a single case of an intestinal round 

 worm of the genus Contracaecum. 



A cecal worm, Subulura strongylina (Rudolphi, 1819) Raillet and 

 Henry, 1912, was found in a single grouse examined by Boughton 

 (1937). The specimen was from Minnesota but the parasite is 



