lo4 [July. 



1893, p. 139). It is smaller, and ma}'' readily be separated by the genal 

 spine outside the eyes, as well as b^^ the carinate junction of the flat 

 discal portion of the elytra with the vertical sides. In this species, as in 

 D. striaticeps, the eye is invisible from below, being almost horizontal 

 in position on the dorsal surface of a lateral projection of the gena ; in 

 D. domiiiiceiisis Horn, and presumably in D. laevipennis Horn, which 

 is unknown to me, it is completely lateral and almost circular in 

 outline, with a considerable interval between it and the neck. 



British Museum (Xat. Ilist.), S.AV. 7. 

 May 1918. 



ON GYNARCHY IN COLEOPTERA. 

 BY D. SHARP, M.A., F.B.S. 



The predominance of the female sex is well known and thoroughl\' 

 ascertained in some of the Orders of Insects, though particulars as to its 

 extent are still much wanted. In ILumenoptera the phenomenon is 

 specially well known, and we need only mention, to illustrate this, the 

 cases of the Hymenoptera Phytoj^haga and Parasitica, as well as the 

 peculiar cases that occur in the Aculeata. But in Coleoptera, so far 

 as I know, but little attention has yet been given to the subject ; it may 

 therefore be of some value for me to record some observations I have 

 made : for -though limited in extent, they may interest others, and 

 induce them to give us the benefit of their experience. 



Ehynchophora. — Some years ago the Russian entomologist, Silantjev, 

 discovered that Otiorrliynclius tiirca is parthenogenetic, and to such an 

 extent that 1000 specimens proved when examined to be all females, and 

 since then it has been found that O. ligustici and O. crihricollis are 

 both gynarchic {cf, Marshall, Faun. Brit. India, p. 25). I have no 

 experience of these species, but I have examined a fair number of speci- 

 mens of O, picipes during the last three years, and have not yet been 

 able to find a male. I have tried some of the largest and some of the 

 smallest specimens, but all are alike in the sexual characters. The 

 spermatheca of the female is very easily discovered and recognizable, 

 and it is well to observe it, because the $ spiculum and ovipositor may 

 give rise to some misconception as to the sex of the individual. 



Strophosomus coryli. — This in Britain is one of the most abundant 

 of the Rhynchophora. Three years ago I attempted to find a male, but 

 without success, and since then I have dissected about one hundred speci- 

 mens, and all of them have proved to be females. 



