Zoology 73 



may have taken place in the fauna but it is interesting to note that 

 Jenyns' recorded the occurrence of three of the larger species of Diptera, 

 the Tabanids, Tahaitiis boviinis L. at Ely and Bottisham and Atylottis 

 riisticus F. at Cambridge, and the large Tachinid Peleteria nigrkornis Mg. 

 on the Devil's Dyke. The identity of the last two can be proved by an 

 examination of Jenyns' specimens, but none of these three has been since 

 taken in the County. An interesting case of the reverse condition is that of 

 the handsome Trypetid Aiwmaea pcnntmda Harr. [aiitica Wlk.). Formerly 

 regarded as a rarity it is now abundant, at least locally, and is freely 

 bred from hawthorn berries gathered near Cambridge. Recently it was 

 found in such numbers on the windows of a house on the outskirts of 

 that town as to be considered a "pest". 



The physical features of a county are always of primary importance in 

 connection with insect life. The Fenland in the north of Cambridgeshire 

 harbours many species not found in the drier strip of the Chalk to the 

 south. This, and the clay strip of south-eastern Cambridge, the river 

 valleys, and the fringe of Breckland on the east, all provide characteristic 

 species (see Figs. 29 and 56). 



Of particular interest is Wicken Fen, where intensive collecting might 

 well produce species unknown elsewhere in the whole country. It was here 

 that the author found the Chloropid Lipara similis Schin. which attacks 

 the growing point of the reed {Phragmites communis) without doing much 

 apparent damage, wliile its close relative Lipara lucens Mg. causes a large 

 gall-like swelling. Here also was found in 1935 and 1936 the tiny midge 

 Pterobosca paludis Mcfie. sucking the juices from the wing-veins of dragon- 

 flies. An unexpected capture in 1936 was that of the rare Syrphid Myiolepta 

 luteola Gmel. ; but some hollow tree on the outskirts of the fen must have 

 been harbouring this species for many years, in the same way that the 

 pollard willow trees at Upware probably accounted for the capture years 

 previously of Xylomyia margiiiata Mg. The occurrence of the rare 

 Odontomyia angulata Pnz. — a marshland species — is not surprising. 



Chippenham Fen, not very far from Wicken, is almost surrounded by 

 woods and plantations and therefore possesses a somewhat different fauna. 

 This is the home of the uncommon Syrphids Chilosia nehuhsa Verr., and 

 Sphegina kiinakowiczi Strbl., and here a specimen of the giant Pipuncuhd 

 Nephrocerusflavicornis Ztt. , and the interesting Conopid wasp parasite Brachy- 

 glossum (or Leopolditis) signatum W. have been taken. Here are also to be 

 found a few rare Trypetids such as Spilographa abrotaiii Mg., Rhacochlaena 

 toxoneiira Lw., and Oxyphora corniculata Fin., and other Acalyptrates 

 such as Ochthiphila coronata Lw., spectabilis Lw., and elegatis Pnz., and 



' See p. 60 above. 



