( xxiv ) 



seems to be rather rare in collections I thought they might 

 be of interest to-night." 



Aberrations of Central European Rhopalocera. — Mr. 

 Douglas Pearson exhibited a drawer of aberrations of the 

 genera Melitaea and Erehia, amongst which were some striking 

 forms of E. stygnc, E. ceto, and M. varia, as well as a remark- 

 ably variegated $ of 31. cntrelia, generally speaking the most 

 constant of the group. 



A New Suborder of Dermaptera. — Dr. Jordan exhibited 

 on behalf of Dr. Malcolm Burr, a pair of Arixenia n. sp., 

 found in vast numbers in a cave in Java, on bats' guano. 

 These creatures are remarkable in that they differ in several 

 essential features from the true earwigs, so that it has been 

 necessary to form a new suborder for their reception. The only 

 other known species was found in the gular pouch of a flying 

 fox, but it is not certain that they are parasites. 



Difference of Food and Habit in closely related Saw- 

 flies. — The President drew attention to a note in the Zeit- 

 schriftfiir wissenschaftliche InseMen-hiologie by Dr. E. Enslin, on 

 closely related species of sawflies one of which was partheno- 

 genetic and the other not. He said that Croesus varus and 

 latipes have very similar yet distinguishable imagines, but 

 quite diffex-ent larvae, and live on different plants ; the larvae 

 of varus is green and lives on alder, that of latipes is black 

 and lives on birch. Von Rossum reared varus imagines (all 

 $ $ ) from alder, which produced a parthenogenetic next 

 brood of larvae. These were fed on birch and became brown, 

 and the resulting imagines showed a tendency to the coloration 

 of latipes. The (? of vanes is almost if not quite unknown, 

 that of latipes is not rare. Von Rossum suggests that varus 

 and latipes may be races of one species varying in characters 

 according to their diet in the larval stage. It is curious that 

 very many saw-fly larvae feeding on alder are almost exclu- 

 sively known in the ? sex, while closely similar species living 

 on birch (when bred artificially) always produce numerous males. 



A discussion on the effects of food arose, in which Messrs. 

 Waterhouse, Cockayne and Fenn took part. Dr. Chapman 

 observed that among the Psychids thei-e are several cases of 

 closely related forms, perhaps of the same species, of which 



