DESCRIPTIONS OP GENERA AND SPECIES. 231 



at this time, when the abdomen is distended by eggs 

 and the function of the bursa is over, a small bursa 

 is apt to be obliterated by the distension of the cuticle ; 

 particularly when it lies between two lobes, as it does 

 in G. sciurinus. As to Kramer's only other species, 

 D. arvicolas, Dujardin, only the hypopial nymph is 

 known, and that stage never shows any sign of sex in 

 any species ; and, of course, never has a bursa copula- 

 trix ; therefore it is not apparent how Kramer knew 

 that it should be put into Dermacarus rather than 

 Glycypliagus, according to his definition. 



Since 1886 we have got to know a little more about 

 the species included in this genus, but it is very little : 

 the hypopial stage is only known in the three or four 

 species known then, and in one of these, Hypopus 

 aruicolge, Dujardin, the adult is not known at all, and 

 in another (if they be different), " Homopus hypudddi" 

 Koch,* the adult is only known from Oudemans' 

 announcement that he has found it,t but he has 

 unfortunately omitted to describe or figure it. In the 

 same place this author states that he has found the 

 adults of three other species and the hypopial nymph 

 of a fourth ; but as he does not describe or figure any 

 of these it is not possible to judge whether they 

 properly belong to this genus at all ; J indeed, it is 

 not possible to be quite certain about Koch's H. 

 hypudgei. Under these circumstances I am still of 

 opinion that it is best, for the present at all events, 

 to leave all the species in the genus Glycyphagus until 

 the life-histories of all are thoroughly known. 



If ever the hypopial nymphs of G. platygaster and 

 G. dispar, if they have any, should be discovered, and 

 should be homopial that is to say, provided with 

 apparatus for holding the hairs of mammals between the 

 ventral surface of the abdomen and certain specialised 

 overlapping chitinous plates near the posterior end, 



* Koch, 1844, < D. 0.,' fasc. xxxix, No. 24. 

 t ' List,' p. 252, called Labidophorus liypudsei. 

 t Oudemans does not name them. 



