J. E. Hull 181 



Whatever the reason may be, it is obviously indisputable, after 

 making every allowance for the imperfection of the numerical test, that 

 the liability to gynandry (in Britain) is strikingly greater in the Linyphiid 

 family than in any other. But I do not think that the tendency 

 can be ascribed to any particular alliance within that family, for the 

 two great branches into which it is divided — the Linyphiine and the 

 Erigonine — are about equally represented among the known gynandro- 

 morphs. 



V. Examples of gynandry in other orders of the Arachnida are yet 

 to seek. In recent years I have had through my hands many thousands 

 of specimens, chiefly Acari (particularly Gamasidae, Thrombidiidae, 

 Oribatidae, and Tyroglyphidae) and have never seen a true gynandro- 

 morph; nor do I know of any record of one. I may, however, here refer 

 to an observation of Canestrini (Prospetto delV Acarofauna Italiana, in, 

 p. 364) on a Tyroglyphid — Rhizoglypkus echinopus F. and R. — which has 

 some bearing on the subject. In maintaining that Hypopus dujardinii 

 of Claparede and Rhizoglypkus rohinii of Michael are dimorphic males 

 of the same species, he says : " My conviction is strengthened still 

 more by the discovery of a male in which one leg of the third pair is 

 incrassate as in Rhizoglypkus rohinii, while the other is of ordinary 

 dimensions " (which is the case with both in the female and in the other 

 form of male, i.e. Hypopus dujardinii Clap.). It would be interesting 

 to know something of the genitalia of this abnormal individual ; for the 

 normal third leg might be either male or female. 



But the total lack of records of gynandry in orders other than 

 Araneae is by no means surprising, for (the Gamasidae and a few other 

 Acari excepted) sexual dimorphism is so slight that the sexes cannot be 

 separated without very close examination. Indeed, in the case of the 

 Oribatidae, it is impossible to distinguish male from female by an 

 external examination, however close. v 



