236 The Ruffed Grouse 



indication that it is a lethal factor. It is also found in the domestic 

 chicken, and its intermediate hosts are several species of snails. 



All authors in reporting on the species of Davainea note the mi- 

 nute size of these organisms and the likelihood of overlooking light 

 infestations. Their prevalence may, therefore, be greater than is 

 shown by the records. 



Raillietina tetragona^ (Molin, 1858) Joyeux, 1927. This species of 

 tapeworm, from two-fifths to ten inches long, occurs primarily in 

 the small intestine, occasionally in the ceca. It was identified (as 

 Davainea t.) in three New England grouse by Dr. Tyzzer and re- 

 corded by Allen and Gross ( 1926 ) . It was found in five out of four- 

 teen young Minnesota grouse by Boughton (1937), aged from a 

 few hours to ten days, and was reported from New Hampshire 

 grouse by Mueller (1941). The species is also known from the 

 bobwhite and other game birds, and infects a species of snail and 

 the domestic fly as secondary hosts. No significance is indicated for 

 this worm as a grouse parasite. 



Choanotaenia infundibulum ( Bloch, 1779 ) Cohn, 1899. Another in- 

 testinal tapeworm, from two to eight inches in length, was reported 

 by Boughton (1937) as the most prevalent cestode in Minnesota 

 grouse. The incidence of infection was about three per cent. It is 

 also found in several other gallinaceous birds. The domestic fly 

 serves as a secondary host. In spite of its widespread distribution, 

 it has not been reported elsewhere in grouse. 



The Trematodes (Flukes). At least five species of flukes occur in 

 the ruffed grouse in the northeast quarter of the United States and 

 eastern Canada. None are knowm to be of any significance as a 

 lethal factor. These worms are probably more prevalent than is in- 

 dicated by the records since they commonly escape notice in routine 

 autopsies, imbedded as they are in the bird's tissues and assuming 

 the same color. Mueller ( 1941 ) notes that his examination of forty- 

 six New Hampshire grouse added two new species of trematodes to 

 the one previously known from this region and suggests this finding 

 resulted because his birds were taken largely from low ground 

 where snails, the intermediate hosts, are abundant. 



Harmostomum pellucidum ^ Werby, 1928 



^ See Boughton ( 1937 ) for complete description. 



