ANIMALS WHICH LIVE ON OR WITHIN GROUSE 185 



adult state in the dog, there was some justification for our hope of 

 finding the larval stage of at least one of the Grouse tapeworms in 

 these insects, but so far we have not succeeded in doing so. The bird- 

 lice form a rather isolated group of insects ; but there is, apart from 

 the fact that their mouth organs are adapted for biting and not for 

 sucking, much resemblance between some of their organs and those 

 of the true lice ; with these but not so closely allied, are the fleas. 1 



Biting-lice are as a rule minute flattened little insects, with poorly 

 developed eyes, a chestnut-brown body, and a generally well-groomed 

 appearance. Five distinct species infest the domestic fowl, and unless 

 the host be unhealthy, they seem rarely to do much harm. 



In 1842 Denny 2 described and figured the broad bird-louse, which 

 he calls the " Louse of the Black and Red Grouse." He states that it 

 is " common upon both the Black and Red Grouse." 3 " Upon the 

 Willow or Hazel Grouse 4 I find a similar but distinct species, rather 

 broader in the abdomen, and of much darker colour." 



Andrew Murray, in his book on Economic Entomology, 5 writing 

 of the broad bird-louse, says : " This is the insect which sometimes, 

 especially in the bad seasons, does so much harm to the young Grouse 

 when they are feeble and unhealthy." 



Goniodes\telraonis is the commonest of the insects which infest 

 the skin of Grouse, crawling about amongst the bases of the feathers 

 and on the vanes of the feathers themselves. It occurs more 

 commonly than the narrow bird-louse of the Grouse/ which is often 

 associated with it. It is comparatively rare to find a bird free from 

 these " biting-lice," but perhaps 10 per cent, is about a fair estimate 

 of the number of uninfested Grouse. The number on each bird is 

 to some extent an^inverse^measure^of^their health. Careful search 

 will discover but two Jor Jbhree on a healthy Grouse, but on a 

 " piner "^hundreds may be met with. 



The^Jbroad ibird-louse^is ^usually found^on^thejsmaller feathers, 

 crawling*about half-way between their insertion and the tip of their 

 vanes. When disturbed they hurry away into the brushwood of the 

 small feathers, like small doer seeking cover, and they are by no means 

 so easy to catch as one at first thinks. They eat the finer barbules of 

 the feathers, which, accumulating in the crop, gives the dark, curved 

 marking in their rather transparent bodies. On this meagre and arid 

 diet they seem to flourish, actively produce young, and pass through 

 several ecdyses or changes of skin. 



The eggs are very beautiful objects ; in badly infested Grouse they 

 may be numerous, but as a rule they are none too easy to find. Usually 



1 Bird-lice, true lice, and fleas are now placed together in the modern group 

 A napterygata. 



2 "Monographia Anoplurorum Britannise," published by H. G. Bohn, London, 

 1842, p. 161, PI. xiii. Fig. 3. 



8 Tctrao tetrix and Lagopus scoticus* 



4 Tetrao saliceti (sic). s Chapman and Hall, London, 1877. 



6 Nirmus cameratm, Nitzsch. 



