174 The Insects of Cambridgeshire 



because in no other English county is there such another 

 piece of original undrained fenland as is found at Wicken. 



A history of this Fen District (which is far the most 

 important from an entomological point of view) will be found 

 elsewhere, and it is only necessary to state here that the 

 greater part has been drained and converted into exceedingly 

 rich agricultural land, by confining the flow of water to certain 

 artificial channels, and pumping the water from the surround- 

 ing land into those channels; only about 300 acres remain 

 to give anyone an idea of what the Fen District was like 

 before it was drained. These 300 acres, which are known 

 as "Wicken Fen," possess a fauna and flora of remarkable 

 interest, and it is to be hoped that they may never suffer the 

 fate that has befallen the rest of the Fen-land. At Chippenham 

 there is another piece of fen-land, which was probably close to 

 the edge of the original Fen District, where it merged into the 

 sandy heaths beginning at Newmarket and culminating in the 

 wild arid country round Barton Mills and Elvedon (Suffolk) 

 and Thetford (Norfolk). This piece of fen-land is also ex- 

 ceedingly rich entomologically, and possesses in many respects 

 a fauna and flora distinct from Wicken Fen because it is 

 more or less surrounded by woods, and consequently in ad- 

 dition to the usual marsh-loving insects and plants, one finds 

 many species peculiar to damp woods ; it is the only locality 

 in England where Temhophorus simplex, Mik., has been found. 



The geological and topographical features of the Southern 

 District show much greater variation; there is the valley of 

 the Cam and those of its tributaries in the South-West ; 

 a range of "chalk hills, which rise to a height of from 300 to 

 400 feet and include the Gog Magog Hills near Cambridge, 

 enter the county at Royston and extend from south to south- 

 east via Linton to Newmarket; south of these hills the country 

 is extensively wooded, and such large woods as Woodditton Park 

 and The Wydghams would probably well repay any collector 

 who would undertake to work them, for such comparatively 

 rare species as Volucella iiiflata, F., Criorrhina asilica, Fin., 



