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ANNALS OF SCOTTISH NATURAL HISTORY 



I can find no authentic l modern record of D. griseo-striatus 

 south of Mull and Easterness. 



Although it is more probable that the Mull record refers 

 to the latter species since that species does occur there 

 I am not inclined to dismiss the possibility of the record 

 referring to H. halensis. I have recently been inquiring into 

 the question of " improbable " or " ectopic " records, and am 

 now inclined to see some significance in them, although they 

 are usually apt to be regarded as due to wrong identification. 



It is obvious that species are always striving to extend 

 their range, and I have elsewhere endeavoured to show that 

 the water-beetles do tend to spread during the summer and 

 are again driven back to their old haunts in the winter. 2 It 

 is to be expected that ectopic records will occur, and there 

 are quite a number of such records for the water-beetles. 



In such a group as the halophil or maritime species for 

 instance there are a number of species for which there are 

 inland records which may be regarded as " ectopic " : 



1 Stephens ("Illustr. Mand." V. p. 391, and "Manual," p. 66) records 

 H. griseo-striatus, De G. , from the north of England (" Carlisle," in Manual), but 

 'Gemminger and Harold treat this as referring to H. halensis, F. They consider 

 Stephens's H. areolatus to refer to Deronectes assimilis, Payk, although in the 

 " Illustrations " Stephens gives it as areolatus of Ditftschmidt which is a synonym 

 for H. halensis, F. , and in the Manual Stephens gives both names for one species ! 



2 ' A Study of the Aquatic Coleoptera and their surroundings in the Norfolk 

 Broads District.' "Trans. Norfolk and Norwich Nat. Soc." viii. 1905 (Paper I.), 

 1906 (Paper II.). 



