282 THK K\l().\rol,l)(ilST"s KKCOHI). 



that tlie (lraj4'()nriies were not driven to swarm for want of food and 

 that, thci'ofore, the tiight was different from the swarms sometimes 

 observed flying over the water, especially if there has been a cold 

 spring- to retard their development. 



The British species of dragontlies may l)e roughly divided into 

 four groups : (1) l^ndoubted sedentary species. (2) Known migrants. 

 (3) Suspected migrants. (4) Casuals or suspects. In the second 

 group I'latctnnii iJrjirrssinii, Lihrllida iiiiailri)ii(icitlat(i, J'Whna ini.rta, 

 and -/•'. iinoKlis have already been dealt with. The suspected migrants 

 are species of exceedingly erratic appearance, and include Si/)iipi'triiiii 

 f()nsr(il())iil)ii, S. tfarcoliini, and S. saniniinruiii. S. fhnscoloiitbii is a 

 widelv distributed species, extending its range to South Africa, and 

 was for many years known as British from single specimens in the col- 

 lections of Stephens and INIcLachlan. Hall then captured it at Deal, 

 and I^riggs took 17, all males, between July Hth-17th, 1892, on 

 Ockham Common, near Wisley, Sui-rey ; B>riggs considers these to 

 have been part of an immigrant swarm, which, from the early date of 

 their appearance, probably came from North Africa. S. rlarcnlum was 

 observed by Miiller in large numbers on August 27th, 1871, on Shirley 

 Heath, ovipositing in and flying around a pond there, whilst Lucas, 

 in September, 1898, found this species, rather worn, but in fair 

 numbers, on Ockham Connnon, and single specimens were also 

 sent for identification from Elstead in Surrey, Oxford, and Col- 

 chester. These evidently appear to have been immigrants, and Lucas 

 suggests that they possibly came from Belgium, whilst the same 

 species has been recorded by l^oubleday as very common in certain 

 years among the gravel pits in Coopersale Common, near Epping, in 

 August and September. Lucas thinks that S. sautpiinciDn, which 

 Doubleday also records as very common among the gravel pits of 

 Coopersale Common in September and October, is also so local and 

 sporadic in its appearance in Britain that it is most probably a visitor 

 to our shores. The occurrence of odd specimens in various localities 

 in 1898 he considers supports this view. One suspects that the 

 British captures of these three species may be either immigrants or 

 the direct progeny of such. The " casuals " possibly owe their places 

 on our list to much the same cause as do certain Sphingids and butter- 

 flies. McLachlan notes that Lrmorrliinia prctoralis is reputed to have 

 been taken on board a fishing-boat at the mouth of the Thames. Two 

 Si/wiictnnii iiioididiiah'yveve recorded long ago as British, but this species 

 is not a very likely native, although it occurs abundantly in the Alps 

 of Central Europe, sometimes ascending to great elevations where it 

 could hardly be expected to breed. OniiclKHiomphn^ {JAndcnia) forci- 

 jiata is in the Stephens' collection (but the example is not too well 

 authenticated), whilst an example of (iomplms fiariiies was captured by 

 Stephens at Hastings on August 5th, 1818, both species being possibly 

 only very occasional visitors in this country. Jjcstex riiidis (one 

 example), Lcxtrs riiriis (two examples), and a single specimen of L. 

 barhara in the Dublin Museum are all badly authenticated as ]>ritish. 

 These three last-named specimens, too, are insects of feeble llight, and 

 it is quite possible that the examples of supposed British origin were_ 

 never really captured in this country. 



The records of dragonfly swarms here given could no doubt be greatly 

 increased bv a more careful hunt through the foreign literature relating 



