ON ISCHNOCERA PARASITIC UPON BRITISH GROUSE 103 



GONIODES TETRAONIS (L.) (l/SS). 

 Host — Black Grouse, Lyrurns tetrix. 



Like Lagopceais canieratus (cf. supra) probably confined 

 to this host. 



GONIODES LAGOPI (L.) (1758). 



As I hope later to show, quite unnecessary difficulties 

 have been made in the interpretation of this name. 



Hosts — Red Grouse, Lagopus scoticus and 

 Ptarmigan, L. imctus. 



This parasite has probably the same host range and 

 distribution as Lagopcccus nffinis. 



It is evident from the foregoing notes that hitherto the 

 Ischnocera of the Red Grouse and the Black Grouse have been 

 confused. Neither "' Lagopcccus canieratus''' nor '"' Goniodes 

 tetrao7ns" have any claim to be considered parasites of the 

 Red Grojise. The host attachment of the Grouse Ischnocera 

 is of a very definite type. Further, we can generalise on 

 the extent to which the insects have lagged behind the 

 birds in the evolutionary race. A parasitic species corre- 

 sponds to a host genus. Closely related species within a 

 parasitic genus here indicate closely related host genera. 

 It is interesting to note that judged by its parasites our 

 somewhat soberly clad Capercaillie has as its near relatives 

 the splendid Impeyan" Pheasants" of the Himalayas (2 spp.). 

 If accidental transference in the game bag be ruled out, 

 I have not yet seen a case of genuine straggling of one 

 of these Grouse Ischnocera. 1 have, however, examined 

 male and female -of Goniodes lagopi, taken from a Golden 

 Eagle {Aquila chrysactus) in Perthshire (see Trans. Perths. 

 Soc. Nat. Sc, vol. v., pt. iv., p. 124, Dec. 1912). In 191 2 

 I did not venture to name this pair, but the suggestion then 

 put forward that they probably came from Tetrao was 

 groundless, as a recent dissection of the male has shown. 



To sum up, our four species of Grouse harbour seven 

 forms of Ischnocera referable to three genera. Of the latter, 

 one {Lagopcecus) is peculiar to Grouse and their immediate 



