9 
1909.] ECTOPARASITES OF THE RED GROUSE. dll 
Giebel* gives the name (loniodes heteroceros Nitzsch as a 
synonym of G. tetraonis, and in his large monograph on ‘ Les 
Pédiculines,’ Piaget T uses the former name without any reference 
to Denny's. The name G. heteroceros also appears in Giebel’s 
article £ on the Epizoa of the Halle Museum, published in 
1866, but only the name. In his article on “ "Parasiten ” in 
von Middendorf’s ‘Reise in den Aussersten Norden und Osten 
Sibiriens,’ Grube attributes certain bird-lice taken from Lagopus 
albus, the Willow Grouse, and from Lagopus alpinus, the 
Ptarmigan, to the species Goniodes tetraonis Denny; but Piaget 
points out certain differences, and seems to consider that a new 
species might have been described from these specimens. 
Andrew Murray, in his book on ‘ Economic Entomology’ §, 
writing of Goniodes tetraonis, 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.” 
It is the commonest of the insects which infest the skin of 
grouse, crawling about amongst the base of the feathers and on 
the vane of the feathers themselves. It occurs more commonly 
than Nirmus cameratus, 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 or three on a healthy grouse, but on a “ piner ” hundreds 
may be met with. This is not, however, the case with birds that 
die quickly of acute disease. 
Goniodes tetraonis is usually found on the smaller feathers, 
crawling about halfway between their insertion and the tip of 
their vanes. When disturbed they hurry away into the brush- 
wood of the small feathers, like small] deer seeking cover, and 
they are by no means so easy to catch as one would at first think. 
They eat the finer barbules of the feathers, which, accumulating 
in the crop, gives the dark curved marking in thew rather trans- 
parent bodies. On this meagre and arid diet they seem to flourish, 
actively produce young, and pass through several ecdyses. 
The naked-eye colour of Goniodes is a yellowish brown. Under 
the microscope the body appears rather transparent, but wherever 
there is chitin this is of a yellowish to chestnut-brown colour 
according to the thickness. The crop, which is full of minute frag- 
ments of the finest barbules of the feathers, presents a blackish 
sac-like appearance, running obliquely across the middle line of the 
abdomen ; asomewhat parallel but much smaller black tube repre- 
sents possibly the rectum (Pls. XL.& XLI.figs.12&16). In afew 
cases the cesophagus and crop presented a red appearance, this 
being probably due to hzemoglobin from the blood of the grouse. 
* “Insecta Epizoa,’ Leipzig, 1874. 
t Leiden, 1880. 
af Zeitsch. f. ges. Naturwiss. xxviii. 1866, p. 387. 
§ Chapman & Hall, London, 1877. : 
