THE ECTOPARASITES OF THE RED GROUSE 357 



Travels " as existing on Lagopus albus and L. alpinus, thus confirming Denny's 

 surmise. 



It is mentioned in Giebel's article l on the Halle Bird-lice, and described and 

 figured in his great monograph " Insecta Epizoa." Piaget, in his " Les Pediculines," 

 states his conviction that N. cameratus is specifically identical with the N". quadru- 

 latus of Nitzsch, from Tetrao urogallus, the Capercaillie. Kellogg in his Mallo- 

 phaga (" Genera Insectorum ") does not mention N. cameratus, though he records 

 N. quadrulatus from T. urogallus, T. tetrix, and Lophophorus impeyanus. 



Nirmus is a more slender animal than Goniodes, and appears to be longer. It 

 is rarer than the latter, though in the great majority of cases the two are found 

 together. Most of what has been said above about Goniodes applies also to 

 Nirmus, as their habits are very similar, except that Nirmus lives more on the 

 skin and upon the base of the rachis of the feather than does Goniodes. It also 

 seems to frequent the feathers under the wing, where Goniodes is seldom seen. 

 Both species seem to wander all over the body ; and though they seem rather more 

 common upon the head, neck, and back, the old view that these biting-lice occur 

 chiefly or exclusively on those parts of the body inaccessible to the beak was 

 not borne out by our investigations. 



The variation in size and in colour is very considerable. Dead specimens are 

 not infrequently found, and these may be in some cases mistaken for cast skins. 

 An average length is 3 mm., and an average width of the abdomen is 1*5 mm. 

 The abdomen is the widest part (PI. LIV. Fig. 1). In no case did we find either 

 Goniodes or Nirmus in the crop of the Grouse, though, as we have just stated, 

 they are fully exposed to being snapped up by the bird's beak if the bird cared to 

 notice them. It is not known exactly how clean birds get infected : probably the 

 Mallophaga simply crawl from one bird to another when the latter are contiguous, 

 and the young birds are infected on the nest. There is evidence, however, that in 

 some cases, probably rare ones, they cling to the Grouse-fly, and are by it trans- 

 ported to a new host. 



In the summer of 1907 Mr Fryer found some Mallophaga eggs. These were 

 for the most part empty, but from one or two full ones he has succeeded in hatch- 

 ing out specimens of Nirmus cameratus. The eggs are white, and trans- 

 parent when empty, just visible to the naked eye, 0'6 mm. in length, and 

 about four times as long as they are broad. Each egg-case is beautifully reticu- 

 lated, the areas between the reticulations being six-sided. At one end the egg has 



1 "Zeitschrift fur gesammten Naturwissenschaft," xxviii. p. 370, 1866. 



