GROUSE DISEASE 569 



times ; the exact number of times is, however, not known but 

 cast skins are frequently met with. The young birds are 

 probably infected with these ectoparasites whilst in the nests, 

 the bird-lice falling from one bird to another when they are 

 contiguous. They have also been known to cling to the 

 grouse-fly and in this manner may be transported to a new 

 host. In no case was any specimen of either of these two 

 species found in the crop of the grouse. 



Two fleas are found on grouse, one rare but the other is 

 a well-known bird-flea which has also been found in the nest 

 of the hawfinch, the dipper, the blackbird, the moorhen and 

 others. Since it is known that a certain dog-flea is the second 

 host of one of the cestodes of the dog and a rat-flea of a tape- 

 worm of the rat, it seems possible that one of these fleas may 

 be the intermediate host of one of the chief worms which 

 infest the alimentary canal of the grouse. We have, however, 

 not succeeded in finding the cysts, neither have we found 

 specimens of the flea in the crop of the bird. 



Then there is a tick, the common rice- or dog-tick, usually 

 attached below the jaw of the bird or to the eyelid or to some 

 other position where the beak cannot reach it. Ticks are 

 responsible for the transference of a very fatal epizootic termed 

 Spirillosis in fowls in the Sudan and for numerous other 

 diseases which afflict man and cattle throughout the world, 

 but ticks are not common on the grouse and the Inquiry 

 has as yet traced no disease to them. In parts of Ross-shire, 

 however, especially in certain woods, these ticks are said to 

 be extremely numerous and the keepers aver that they fre- 

 quently kill off large numbers of black-game. They are 

 commoner during the spring and early summer but usually 

 disappear at the beginning of July. Curiously enough a 

 common cheese- or flour-mite was from time to time found in 

 considerable numbers on the skin of the grouse and apparently 

 these mites sucked the blood of their host for their alimentary 

 canal contained red food. 



Finally, there are a couple of true flies, the well-known 

 grouse-fly which is apt to crawl up the sleeves of those who 

 handle grouse in the early autumn. The grouse-fly belongs 

 to the same group as the horse-fly and the sheep-tick. The 

 latter, however, has lost its wings and burrows in the wool 

 of the fleece, Most members of the family to which this grouse- 



