SCIENCE-GOSSIP. 



BRITISH DRAGON FLIES. 

 By Charles A. Briggs, F.E.S. 



A MONG the lesser-known, or rather less 

 *■*■ popularly known, groups of insects there 

 are few, if any, that exceed in interest the 

 dragonflies. 



Whether we regard the marvellous structure 

 and habits of the carnivorous aquatic larvae, or 

 the singular beauty of the perfect insects them- 

 selves, the group certainly is deserving of far 

 more attention than our entomologists have 

 hitherto given it. 



Forming as. it does a section of the pseudo- 

 neuroptera so distinct that the separation of the 

 odonata, or dragonflies, into a distinct order 

 seems almost a necessity, the group is so distinct 

 from all other insects found in the British Islands, 

 so easily, worked, and so small that it may be 

 taken up and mastered by anyone with com- 

 paratively little difficulty or doubt. 



As compared with other groups of insects 

 dragonflies are of large size, the smallest of our 

 British species being nearly an inch in alar ex- 

 panse. Although, when the specimens are old 

 and discoloured a good lens is needed for 

 determining with certainty the identity of some 

 closely allied species ; yet while the insects are 

 fresh, they may, with perhaps one or two ex- 

 ceptions, be easily determined by the eye alone. 



The difficulty which has always stood in the 

 way of beginners has been the absence of any 

 reliable English work on the subject, Dr. Hagen's 

 excellent monograph in the " Entomologists' 

 Annual," for 1857, being so brief that it is 

 scarcely adapted to the wants of the beginner, 

 while the painstaking books of Stephens and 

 Evans are practically useless owing to their 

 antique nomenclature and the erroneous views 

 of species which cloud them. 



Recently, however, Mr. Harcourt Bath, in his 

 "Illustrated Handbook of British Dragonflies' 

 has made a step towards enabling the beginner to 

 name his specimens, and this work, though very 

 incomplete, especially in the descriptions of the 

 Agrionina, ought to be in the hands of every lover 

 of the group ; while the price is so low as to be 

 within the reach of everyone. 



For those who can afford a somewhat more ex- 

 pensive work, the magnificent plates in Charpentier's 

 " Libellulinas European " will prove most useful, 

 but the nomenclature must be corrected by 

 McLachlan's " Catalogue of British Neuroptera." 

 The standard work, however, is Selys Longchamp's 

 " Revue des Odonates." This work, dealing with 

 the whole of the European dragonflies, and con- 

 trasting and comparing as of necessity it does in its 



descriptions, species which do occur in Britain 

 with species which do not, is somewhat confusing 

 to the beginner, yet sooner or later it must be 

 consulted by everyone. 



The total number of the species of dragonflies 

 occurring in the British Isles is only forty-six, and 

 even of these eight species are but chance visitors, 

 five of them, viz., Lcucorrhinia pectoralis, Onycho- 

 gomphus forcipatus, Gomphus flavipes, Lestes viridis, 

 and L. barbara being represented here by solitary 

 examples, taken many years ago. Two others, 

 viz., Sympctnim meridionalis and Lestes virens by 

 two examples, also of old date ; while the eighth, 

 Sympctvum fouscolombii, was represented by only 

 three examples, until the chance discovery by 

 myself of a flight of them in Surrey, in 1892, added 

 seventeen more specimens to the record. 



Of the remaining thirty-eight species, three, viz., 

 Cordnlia arctica, C. metallica, and CEschna borcalis are 

 not found in England, being confined to the High- 

 lands of Scotland (or in the case of C. arctica at 

 Killarney also), three, viz., Cordulia curtisii, Agrion 

 mercuriale and Ischnura pumilio are confined to 

 Hampshire and the south-west of England 

 (/. pumilio has, strange to say, been recorded also 

 from Kilmarnock), and one species, CEschna rufescens, 

 is restricted to the Fens of the Eastern counties, 

 and until a single specimen was taken last year 

 had not been recorded for many years. 



This leaves thirty-one species for the general 

 collector to seek for. Probably all of them, except 

 Libcllula fulva and Lestes nymph a might be obtained 

 in a couple of years' work in varied localities. I 

 have myself taken twenty species from round one 

 large pond in Surrey, and there are two or three 

 other kinds I still hope to take there. 



Our dragonflies are divided into two main groups, 

 the Libellulina and the Agrionina, the former con- 

 taining the stout-bodied, swift-flying species, the 

 latter the slender-bodied, slow-flying ones. 



The first group, the Libellulina, contains the 

 bulk of the British dragonflies, and is also well 

 represented in a fossil state. It is certainly re- 

 markable that while the remains of these and other 

 insects in the Lias so closely resemble our own 

 species of to-day that they can with ease and 

 certainty be referred to existing families and [even 

 genera, yet the mammals from the same formation 

 chiefly consist of the Saurians and other creatures 

 long since extinct. 



The Libellulina contains four families, twelve 

 genera, and twenty-nine species. 



The first family — the Libellulida? — contains five 

 genera, viz., Lcucorrhinia (two species), Sympetrum 



