362 THE GROUSE IN HEALTH AND IN DISEASE 



The mouth is bordered by tumid lips, above which the hook-like mandibular 

 sclerites are pulled and pushed in and out. Dorsal to these again are two eleva- 

 tions which each bear two sensory papillae ; these correspond with the sensory 

 tubercles of M. domestica, though the latter are not borne on an elevation. 



The anus opens on the truncated thirteenth segment, well forward on the 

 ventral surface ; around it, symmetrically placed, are four anal papilke, which 

 assist in the movements of the maggot. 



The ti'acheal system opens on the flattened posterior end, about the centre. 

 Ventral to the stigmata there are two or three pairs of low papillae. Each stigma 

 leads into a trachea, which almost immediately divides into a visceral branch which 

 bends down into the viscera and extends a little way in front of the middle of 

 the body. Before splitting in M. domestica the right and left main trunks are put 

 into communication by a transverse trunk ; if this exists in S. stercoraria it 

 escaped our notice. The lateral trunks give off in each segment a dorsal and 

 ventral twig. Anteriorly, in what appears to be the third segment (it is described 

 as the fourth in the house-fly), there is a transverse commissure by means of which 

 the right and left trunks are put into communication. In front two small twigs 

 are given off from this transverse commissure which run to the pharynx. The 

 main trunk is continued forward, and at the second segment (the third in the 

 house-fly) it ends in a process like a little rake. This is due to the splitting up of 

 the trachea into eight or nine little twigs, all in the same plane and all ending in 

 a knob. The whole is called the anterior spiracle, and can be protruded from the 

 body and retracted. Hewitt states that in the house-fly each of these knobs opens 

 to the surface by a very minute pore. 



C. SiPHONAPTERA. — Fleas. 



(i.) Fam. Pulicidae. 



V. — Ceratophyllvs jallisvljS Dale.' 



Synonym : Ceratophyllns (TrichopsyUa) newsteadi' Rothsch. 



I am indebted to my friend Mr N. 0. Rothschild for identifying this flea, 

 which is here recorded for the first time from the Grouse. It is a well-known bird- 

 flea, having been found in the nest of the hawfinch, Coccothraustes vulgaris, in 

 that of the dipper, Cinclus aquations, in that of the blackbird, Ttirdus merula, 



' N. C. Rothschild, Entonwlorrists' Monthly Magazine, II., ser. xiv. i>. 14.'), 1903. 

 * Entomologists Record, xiii. p. 284, 1901. 



