102 Mr. F. Balfour-Browne on the 



there is, at the extreme apex of tlie elytra, a mere trace of 

 puncturation only to be found under very iiigh masjnification 

 and by careful manipulation of the light, but I find a similar 

 trace in a small specimen sent me by Edwards as H. heydeni, 

 and which I certainly regard as such. 



Although therefore it is not correct to describe H. rufi- 

 colUs as dimorphic, as suggested by Bedel — since all intei- 

 mediate stages seem to exist between the extremes, — we may 

 perhaps describe the completely punctate female as the 

 "insular^' form and the one in which the fine puncturation 

 is reduced as the "continental" form, and it is interesting 

 to note that, so far, the only specimens of the continental 

 form which I have seen from the British Islands are from 

 the south-east of England (Cambridge, Surrey, and Kent 

 East). 



From what has been said, it is quite clear that very little 

 reliance is to be placed upon tlie elytral puncturation for 

 determining the females of H. ruficollis, and, unfortunately, 

 it is not only this species which is variable in this character. 

 Edwards describes tlie females of H. ivelinckei as having the 

 apical half of the elytra finely punctured and the basal half 

 impunctate— and in many cases this is no doubt correct, but it 

 is not always so. A few specimens taken by me in brackislt 

 pools by the River Bann, near Coleraine, Co. Derry, are, all 

 except one, very faintly punctured to the base of tiie elytra. 

 I determined these specimens, first, on the ground that only 

 male loehnckei occurred in these pools, and, secondly, on the 

 general form, which is typical of the " wehnckei" group as 

 opposed to the " ruficollis " group. Again in sixteen out of 

 eighteen female wehnckei taken in one spot in the Lagan 

 Canal, near Belfast, the elytra are punctured to the base, 

 although the puncturation is in some cases extremely fine. 

 Nineteen male we/inckei occiuved in this collection, and no 

 male rvficolU.", and, excepting in the character of elytral 

 puncturation, the females do not in the least suggest 

 7'uficollis. 



In collections made in the River Spey and in some drains 

 in the Aviemore district (Inverness East), very faint punctu- 

 ration can be seen at the base of the elytra of most of the 

 loehnckei females and a few are strongly punctured through- 

 out. 



I could give a number of other examples to show that the 

 puncturation of the elytra of females of H. wehnckei tends to 

 vary in our Islands, in some cases covering only the apical 

 half, in others covering the whole of the elytra, and there 

 are all grades betv^^een the extremes. My knowledge of con- 



