RUFFED GROUSE 163 



Lyponyssus sylvarium. Several individuals of a flock of ruffed 

 grouse kept in captivity at Brunswick, Me., were killed by an infes- 

 tation of myriads of these blood-sucking mites. 



" The hippoboscid fly Omithoponus amerlcanus is light brown 

 and about the size of a common house fly but with longer wings and 

 with a radically different life history and behavior. This fly is very 

 active and difficult to secure since it is quick to disappear among the 

 feathers or it may leave the bird entirely. The flies attack the birds 

 in the region of the head, where they suck the blood of the host and 

 are thus capable of bearing blood parasites and diseases." 



The internal parasites are more numerous, of greater importance, 

 and apparently more often prove fatal. Of these Doctor Gross 

 writes : 



" The internal parasites are chiefly in the alimentary tract, where 

 they are introduced along with the food, chiefly in the form of eggs 

 and larvae. The life histories of some of the parasites involve a 

 secondary host. 



" The crop worm Thominx annulata is an extremely slender worm 

 found beneath the epithelial lining of the crop and gullet. It is 

 from 2 to 3 inches long, but less than the diameter of a hair. The 

 walls of the crop and gullet are very much thickened and thrown 

 into folds and ridges by the presence of this parasite. 



" The stomach worm Dispharynx spiralis is one of the most im- 

 portant of the internal parasites. In southern New England and 

 New York State a large percentage of the birds found dead and 

 examined, died from the effects of this nematode. Dispharynx spir- 

 alis is between one-fourth and one-half of an inch in length, pointed 

 at both ends, and always rolled up in a characteristic spiral form. 

 It becomes established in the glandular walls of the proventriculus 

 and in advance cases of infection this region is so excessively swollen 

 as to equal the size of the gizzard. The worms become sexually 

 mature in the grouse, and great numbers of eggs are passed through 

 the alimentary tract and eliminated with the droppings. The eggs 

 will not develop if taken directly into the body of another grouse, 

 but the life cycle involves an intermediate host, which Dr. Eloise 

 B. Cram, of the United States Bureau of Animal Industry, working 

 with the New England ruffed grouse investigation, has found to 

 be the pillbug. 



" The gizzard worm Gheilospirura spinosa is distributed over a 

 wide range from Maine to Pennsylvania and west to Wisconsin. In 

 Wisconsin it is second only to Ascaridia lineata in the percentages of 

 cases of infection. Gizzard worms are slender, the female obtain- 

 ing a length of iy 2 inches. They are usually found between the 

 chitinous lining and muscular walls of the gizzard. Like Dis- 



