218 De Selys Longchamps on the British Libellulidse. 



that I am indebted for having been able to throw light upon the 

 synonymy of the British Libellulidse, by numerous comparisons. 

 I must particularly mention the following gentlemen : — Mr. E. 

 Doubleday, who facilitated my researches in the British Museum, 

 and in the collection of the late Dr. Leach, which is deposited 

 there ; — the Rev. F. W. Hope of London, whose museum is an 

 inexhaustible source of study for all branches of entomology ; — 

 Mr. J. F. Stephens of London ; — Mr. John Curtis of Hayes ; 

 [The collections of these two last gentlemen are classical for 

 British entomology.] — Mr. W. Evans of London; — Mr. West- 

 wood of London; — Mr. E. Newman, with whom I visited the 

 typical collection of Linnaeus, and that of Sir J. Banks, deter- 

 mined by Fabricius; both of them deposited in the Linnsean 

 Society of London ; — the Rev. Leonard Jenyns of Swaffham Bul- 

 beck ; — Mr. Babington and Mr. Wollaston of Cambridge ; — Mr. 

 R. Ball, who procured for me admission to the Irish collections 

 at Dublin, and especially that of Miss Ball, his sister ; — Mr. W. 

 Thompson of Belfast, who rendered me the same service in the 

 collections of Messrs. Haliday, Hyndman, &c. ; — Dr. Balfour and 

 Dr. Colquhoun of Glasgow; — Dr. Greville and Mr. Wilson of 

 Edinburgh; — Mr. J. Blyth of Glasgow; — Mr. Wailes and Mr. 

 Hancock of Newcastle. 



I had not time to visit the collection of Mr. Dale in Dorset- 

 shire, so rich in British Libellulidse, but that entomologist has 

 furnished me with very detailed accounts ; and as I have seen in 

 the British Museum typical specimens sent and determined by 

 Mr. Dale, I can supply this omission and cite his observations 

 with precision. I must here bear witness to the perfect ac- 

 quaintance which Mr. Dale possesses with the family of insects 

 which is now under our consideration. 



I hope that I have not committed any error as to the deter- 

 mination of the species in the collections, and have not omitted 

 any species. Doubtless many others will be discovered in making 

 new researches, and some which have only been observed in En- 

 gland exist also in Scotland and Ireland, these two last countries 

 having been little explored for this purpose. This list contains 

 forty-six species ; eight of them *, resting on the capture of only 



* I must however remark, that on visiting, from the 15th to the 25th of 

 July, several apparently very favourable localities in Scotland, and that in 

 very fine weather, I was much surprised not to see there, so to speak, any 

 Libellulidse, except the JEschna juncea in small numbers, and some Libellula 

 scotica, Agrion minimum, pulchellum, cyathigerum and elegans, and more- 

 over not in all these localities, which are — Tarbet (Loch Lomond), Inve- 

 rary (Loch Fine), Oban, Foyersfall. In the marshes above these celebrated 

 waterfalls, I did not see any Libellulidae. Is this to be atti-ibuted to the 

 composition of the waters, which themselves depend on the geological con- 

 stitution of the country? The Ardennes in Belgium, the uncultivated heaths 



