ANIMALS WHICH LIVE ON OR WITHIN GROUSE 187 



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 the broad bird-louse applies also to the narrow form, as their 

 habits are very similar, except that the latter lives more on the skin 

 and upon the base of the shaft of the feather than does the former. 

 It also seems to frequent the feathers under the wing, where the broader 

 form is seldom seen. Both species appear to be able 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 has not 

 been borne out by recent investigations (PL xvin. Fig. 1). 



Some eggs of this form have been found. These were for the most 



Eart empty, but from one or two full ones specimens of the insect 

 ave been hatched out. The eggs are white, and transparent 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 marked 

 with a network of ridges, the areas between the ridges being six-sided. 

 At one end the egg has a cap which is pushed off when the young 

 emerges. The eggs are laid between the barbules of the feather- vanes 

 or near the bases of the filo-plumes or short hair-like feathers, and 

 adhere to their supports by means of some sticky excretion (PI. xvin. 

 Fig. 2). 



The eggs appear to be laid during the summer ; the first time they 

 were found (some of them were empty) was on 2nd July 1907, they 

 were found again later in the season. 



There is no metamorphosis or change of the larva into a chrysalis, 

 and then into the adult form, as for instance in butterflies. The young 

 emerge from the egg-case as small miniatures of their parents. They 

 seem to cast their skin several times, but the exact number of times is 

 not known. Dead specimens and cast skins were frequently met with. 



In no case were either of the two species found 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 bird- 

 lice simply crawl from one bird to another when the latter are con- 

 tiguous. There is evidence, however, that in some cases, probably rare 

 ones, they cling to the Grouse-fly and are by it transported to a new host. 



B. SlPHONAPTERA. Fleas. 





 (i.) Fam. PULICID^E. Fleas. 



III. Ceratophyllus gallinulce, Dale. 1 



We are indebted to Mr N. C. Rothschild for identifying this flea, 

 which is here recorded for the first time from the Grouse. It is a 



1 N. C. Rothschild, Ent. Mag., 2nd Ser., xiv., 1903. In the Ent. Ret. Tin., 1901, 

 No. 10, Rothschild described this under the name synonym of Ceratophyllus 

 (Trichopsylfa) newsteadi. 



