102 Mr. F. Balfour-Browne on the 



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

 puncturation only to be found under very high magnification 

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

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

 and which I certainly regard as such. 



Although therefore it is not correct to describe //. rttfi- 

 coIUs as dimorphic, as suggested by Bedel — since all inter- 

 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 wliich 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 the elytral puncturation for 

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

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

 Edwards describes the females of //. loehnchei 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 brackish 

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

 except one, very faintly punctured to tlie base of tlie elytra. 

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

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

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

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

 eighteen female xoehnckei 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 wehnckei occurred in this collection, and no 

 male rvficollif, and, excepting in the cliaracter of elytral 

 puncturation, the females do not in the least suggest 

 ruficollis. 



In collections made in the Biver 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 

 u'eJnickei 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 between the extremes. j\Iv knowledge of con- 



