108 THE ENTOMOLOGIST. 



OBSERVATIONS ON BRITISH ODONATA. 

 By W. Haecourt Bath. 



I WAS exceedingly interested with Mr. Arkle's paper (Entom. 

 35 — 58) on the Dragonflies of the Dee Valley. One very 

 common species, I notice, is not mentioned in his list, namely, 

 Platetrum depressum, which most likely occurs within the district, 

 although it is no doubt very local. Last season I saw several 

 specimens of this insect at Arthog, in North Wales, and also 

 possess examples in my collection from Welshpool, which 

 localities are, however, both just outside the area in question. 

 This well-known species is universally distributed, and very 

 plentiful throughout the south of England, but appears to 

 become scarcer the more one travels northwards. 



Another common species, not included in Mr. Arkle's list, 

 is jMschna cyanea, which is the most familiar member of its 

 family in south Britain, a closely allied species, Mschna juncea, 

 appearing to monopolise this position in Scotland and Ireland. 

 These two species are never known (at least as far as my 

 experience goes) to occur together in the same locality, and the 

 same also holds good as regards Calopteryx virgo and C. 

 splendens. 



Undoubtedly the best species mentioned in Mr. Arkle's paper 

 is Leucorrhinia dubia, which, however, is generally found in 

 abundance wherever it occurs, frequenting many mosses and 

 moors in the North of England. I may here remark that the 

 locality given for the species in my ' Illustrated Handbook of 

 British Dragonflies' as "Thorne Moor, near Dorchester," is, I 

 find, after considerable investigation, Thorne Waste, near Don- 

 caster. There is no such place in Dorsetshire, although it is 

 recorded as such in the works of several authors, in copying 

 from whom I fell into the same error, which I take this oppor- 

 tunity of correcting. 



Mr. Arkle rather amuses me by the way in which he makes 

 use of the ** mother-tongue " names of dragonflies ; one would 

 think they had been in use for half a century at the least. They 

 were in fact only invented by myself about four years ago, and 

 were not intended for the use of scientific students, but simply to 

 popularise the study of these grand insects among young 

 beginners who, as a rule, object to the use of long Latin cogno- 

 mens. Some entomologists may perhaps be inclined to ridicule 

 them, but I do not consider they are more absurd than the 

 familiar names by which most butterflies and moths are known. 



It seems to me incomprehensible that more entomologists do 

 not study and collect these grand insects, considering how much 

 in evidence they always are during every summer ramble. In 

 size they are, as a group, not eclipsed by any other in this 

 country. Some of the species of ^schnidcs, on account of their 



