14 Mr. Arthur E. Shipley [Feb. 3, 



bird-lice, perhaps hardly 10 per cent., and the number on each bird 

 is to some extent a measure of its ill-health. On a healthy grouse 

 perhaps but two or three are found. They are animals with stout and 

 powerful jaws, which they use to bite off the barbules of the feather 

 or the finer plumules which form their sole nutriment. What fluid 

 they obtain to moisten this somewhat dry nutriment is not apparent, 

 but the animals are active and by no means so easy to catch as one 

 at first thinks. They lay very Ijeautiful eggs attached in small groups 

 to the base of the after-plume of the feather or between it and the 

 main shaft. The young hatch out as miniatures of the parents and 

 there is no metamorphosis. The same species occurs on the Black 

 Grouse and upon the Willow or Hazel Grouse. On a piner these 

 bird-lice increase enormously in number, and their numbers to some 

 extent serve as a measure of the gravity of the disease. Both of 

 these bird-lice cast their skin several 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 ])ird 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 

 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. 



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 trans- 

 ference 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 frequently 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 ali- 

 mentary canal contained red food. 



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



