276 THE ENTOMOLOGIST. 



33. ToRYMus CAMPANULA, Cam. 

 Torymus camjKinidce, Cameron, Ent. Mon. Mag. 1880, 40. 

 Rare in galls of Cecidomyia campanulce ; Clydesdale. 



34. Torymus viridis, Foer. 

 Torymus viridis, Foerster, Beitr. z. Mon. d. Ptero. j). xxx. 

 Rare. Clydesdale ; in galls of Bhodites eglatiterice. 



35. Torymus pruni, Cam. 

 Torymus pruni, Cam. Trans. Ent. Soc. 1883, 196. 

 Milngavie ; in galls of Cecidomyia iwuni, Kalt. 



VAEIATION IN THE GENUS EREBIA. 



By Geoffrey Smith. 



Part I. 



During this and previous years I have collected this genus in 

 the English Lake district, and in Savoy, with the purpose, shared 

 by so many collectors, of studying its variability, and the problems 

 connected therewith. The work of Dr. Chapman (Trans. Ent. 

 Soc. 1898), who has based a means of identifying the different 

 species by means of the gonapophyses of the male, has cleared 

 the way for such studies, and is, I believe, absolutely reliable. 

 It is a well-known fact that the various species of Erehia are 

 extremely variable in their wing-facies ; even when whole groups 

 have been separated as persistent varieties from a type-species 

 on the characters of their gonapophyses, &c., the various sub- 

 groups or varieties are not at all homogeneous. There is great 

 individual variability. 



Side by side with this fact I should like to mention another 

 fact even more striking, and that is the great preponderance of 

 males over females in the majority of species. These two facts 

 seem to me to be the leading facts with regard to the genus, 

 and from habitually considering them together 1 have been led 

 to suppose that there might be some causal connection between 

 them. In trying to establish a causal connection between these 

 two facts, it was necessary to treat the subject from a more or 

 less statistical point of view ; I have therefore used the means 

 explained in Prof. Galton's 'Natural Inheritance' for drawing 

 out a scheme of distribution of characters. The application 

 of this scheme will become obvious during the course of this 

 essay. 



I have selected for the purpose in hand Erehia epiphron var. 

 cassiope. This variety, in the regions in which I have studied it, 



