364 THE GROUSE IN HEALTH AND IN DISEASE 



specimens were fixed on the chin or around the eyelids in fact, in such positions 

 as the Grouse cannot reach with its beak. In parts of Ross-shire, especially in 

 certain woods, these ticks swarm in enormous numbers, and the keepers assure us 

 that they kill large numbers of young blackgame. Hence there is nothing remark- 

 able in finding this species from time to time on the Grouse, where its presence 

 must be regarded as accidental. The larval stages emerge from the eggs, and 

 probably crawl on to the heather, and thence on to the Grouse or other animals 

 which come in contact with the vegetation. We have found both larvae and 

 nymphs amongst the feathers, but in small quantities and on rare occasions. We 

 have never found it in the crop, and it can hardly play any part in infecting the 

 bird with tapeworms. 



Ixodes ricinus, or the " castor-bean tick," as it is called in America, is common 

 in many parts of the world. It is reported from sheep, goats, cattle, horses, deer, 

 dogs, cats, foxes, ferrets, hedgehogs, hares, rabbits, bats, birds, and man. This 

 tick occurs most frequently during the spring and early summer, but can be found 

 in lesser numbers up till September and October, possibly later. 



Severe epizootics amongst fowl of spirillosis and of another obscure but very often 

 fatal disease have been described by Balfour l in the Sudan. The spirochaete, probably 

 Spirochcsta gallinarum, which causes the first-named disease is transferred from one 

 fowl to another by a tick, Argas persicus. The second, and as yet rather obscure, 

 disease is recognised by the natives, and by them associated with the presence of the 

 Argas. We have found no traces of such disease in Grouse, and the recorded number 

 of ticks taken in the Grouse is, except locally, so small that they can hardly play 

 any part in " Grouse Disease." 



(ii.) Fam. Tyroglyphidse. 

 VIII. ALEUROBIUS FARING (De Geer). 



Synonym : Tyroglyphus farince Gerv. 



Mr C. Warburton has kindly identified for us a small mite which was found in 

 considerable numbers on several birds and at varying times of the year. Whilst 

 very common at Easter time, they were less,abundant in July. Aleurobius farince, 

 sometimes known as the flour-mite, occurs in great numbers on all sorts of organic 

 material grain, straw, hay, tobacco, flour, cheese, dead bodies, etc., etc. At times 

 workmen handling corn, cats, horses, etc., have suffered much cutaneous irritation 



i British Medical Journal, No. 2445, p. 1330, November 9th, 1907. 



