1909. | ECTOPARASITES OF THE RED GROUSE. 323 
appear to be deposited amongst the feathers and are easily 
detached from them. The few we have found either dropped on 
some paper over which we were handling some birds, or lay loose 
at the bottom of the cardboard boxes in which grouse travel. 
Probably they take some eight or nine months before they give 
rise to the imagos, and the latter very likely disappear altogether 
from about October till June. Further research is needed tc 
throw light on these questions. 
Three specimens of O. lagopodis, all of them taken from one 
grouse, were themselves markedly infested with an ectoparasite, 
a species of mite. Here I refrain from quoting Dean Swift. 
The mite belongs to the genus Canestrinia, as my friend Mr. C. 
Warburton has kindly told me, and is probably a new species. 
The subfamily Canestrinine are all parasitic upon insects, and 
are regarded as harmless. Our specimens existed in considerable 
numbers, clustered round the hinder end of the fly’s abdomen on 
the ventral surface, with their proboscides plunged into its body. 
Many were laying eggs, and many cast-off cuticles were lying 
around. Eggs from which the larve had escaped presented a 
spindle-shaped outline; others contained ova in various stages of 
differentiation ; others fully formed larvee. 
We have in no single case found a grouse-fly in the crop of a 
grouse, nor have we yet found any cestode larve or cysts in the 
bodies of the flies which we have cut into sections or dissected. 
Gi.) Fam. Scatophagide =Scatomyzide. 
LV .—SCATOPHAGA STERCORARIA lL. 
This fly cannot be looked upon as an ectoparasite of the grouse, 
but it lays its eggs in grouse-droppings, and its maggots live on 
and in these dejecta. The maggots must therefore constantly be 
in close contact with and possibly eating the ova of the tape- 
worms which exist in such vast numbers in the grouse-droppings ; 
and here we thought it was a profitable object to investigate for 
the cysticercus or second stage of the cestode. It should be 
mentioned that the droppings consist of two parts: (1) the dejecta 
from the intestine strictly speaking, and (2) the more fluid dejecta 
from the ceca. The latter pass last and lie like a cap upon the 
former. The fly-maggots are only found in numbers in the 
“cecal” part of the dropping. Mr. Fryer first found them 
commonly at Fort Augustus in April. In June they were not so 
common, owing perhaps to the rain which washed the cecal part of 
the droppings away. We examined a Jarge number of the larve 
both by squashing them and cutting them into sections, but we 
found no trace of infection; in fact, here, in this most likely 
place, we again drew a blank. No specimen of S. stercoraria of 
of its larve has been found in the crop. This fly, which, as 
