188 THE GROUSE IN HEALTH AND IN DISEASE 



well-known bird-flea, having been found in the nest of the hawfinch, 

 in that of the dipper, in that of the blackbird, the moor-hen, and others. 

 In the thousands of Grouse which passed through the hands of the 

 Committee only one or two specimens of this flea were found (all in 

 1906), and none were found in the crop. Hence, although the dog-flea, 

 Pulex serraliceps Gerv., is said to be the intermediate host of the 

 dog tapeworm, 1 it does not seem at present very possible that the 

 Grouse-flea could play any part in the life history of the Grouse 

 tapeworms. On the other hand a flea may easily escape notice in 

 the crop contents, and this species is probably much commoner in 

 the nests than on the birds when flying. It has been suggested that 

 there may be a connexion between the seasonal occurrence of k the 

 transparent tapeworm and the life history of the flea. The view is 

 strengthened by Minchin's recent discovery of the larval form 

 (cysticercus) of a tapeworm 2 in an allied species of flea 3 which lives 

 on the rat. As this species of Grouse - flea had not hitherto been 

 accurately figured, t Mr Edwin Wilson drew both male and female, 

 and the drawings were reproduced in the original report. Now that 

 the role of the flea in carrying certain human diseases is recognised, 

 it is well to have them accurately delineated, as in a flea every hair 

 tells. (PI. xix. Fig. 2.) 



IV. Ceratophyllus garei, Rothsch. 



This second species of flea was found in a Grouse in 1907 ; but only 

 one or two specimens were taken. It is recorded by Evans 4 from the 

 nest of the lapwing, and of the ring-dove. Rothschild 6 has found it 

 in the nest of a water-hen, and he records that it has been taken from 

 the stoat, the weasel, the shrew, the vole, and the water-rat, and 

 from hedge-clippings. 



C. DIPTERA. Flies, 

 (i.) Fam, HIPPOBOSCID^E. Horse-flies. 

 V. Ornithomyia lagopodis, Sharp. The Grouse-fly. 



This family includes besides the Grouse-fly, the horse-fly, sometimes 

 known as the forest-fly, the sheep-ked, which has lost its wings and 

 burrows in the wool of the fleece, and a third species which infests red- 

 deer. This last has wings when young, but when the flies find a suit- 

 able host they get rid of their wings and nestle among the fur. Most, 

 however, of the members of this family li ve on birds, and they seem 

 particularly to frequent the swallows and allied species. 



1 Dipylidium caninum. 



2 Thought by Mr Nicoll to be Hymenolepis diminuta (Rud.), a tapeworm of the rat. 



3 Ceratophyllus fasciatus. * "Ann. Scot. Nat. Hist.," 1906, p. 163. 

 5 EnL Mag., 2nd Sen, xiii., 1902, p. 225. 



