Thursday, Fehruanj 22nd, 1917. The President in the Chair. 



An exhibition of Lantern Slides. Mr. West (Ashtead), slides showing 

 androconial scales of several species in each of the families of butterflies 

 represented in the British fauna. Mr. Hugh Main, slides showing (1) ova of 

 the Earwig in situ; (2) a series of details of the life-history of a small burrow- 

 ing beetle common in Epping Forest ; (3) a series illustrative of the transforma- 

 tions of Dijtiscus marginalis ; (4) a series of the habits of the larva of Cicindela 

 campestris. Mr. Bunnett, slides ilhistrating all stages of a colony of Vanessa 

 io. — Ht. J. TuKNBK, Hon. Report. Secretary. 



ON THE RAEITY AND RESTRICTED DISTRIBUTION OF 



ANIMAL— ESPECIALLY INSECT— SPECIES. 



BY GEO. B. WALSH, B.Sc. 



(Continued from p. 61.) 



Examples of these environmental cliancjes are by no means diffi- 

 cult to find : (a) the destruction of forest land in England, besides 

 removing many possible sources of food, has affected the climate of 

 the country by reducing the rainfall and raising the temperature, it is 

 said, by about 1° F. ; and thus other species have been affected besides 

 those which are purely sylvicole ; (b) in France, the indiscriminate 

 destruction of forests by the peasantry during the excesses of the 

 French Revolution caused the loss of the tree-roots which bound the 

 soil together on the slopes of the Auvergnes and the Vosges ; conse- 

 quently the soil and sub- soil were removed from large tracts of hillside 

 owing to the erosive action of the rain ; this is not now retained by 

 the soil and plants in the hills where it falls, but runs directly into the 

 rivers, filling them rapidly much above their usual level and thus 

 causing devastating floods in their lower courses, for example, near 

 Orleans, on the Loire ; this destruction of forests, therefore, besides 

 affecting to their disadvantage the upland species which found their 

 habitat there, reacts inimically upon lowland species far removed from 

 the original forests* ; (c) in the Landes of sovith-western France, until 

 the planting of a long and thiclc littoral belt of pine-trees, the sea- 

 sand drove steadily inwards, destroying arable and grass land, and 

 causing an entirely new type of environment to spring vip there ; and 

 {(I) to quote one more of many possible examples, the progressive 

 desiccation of Central Asia is causing great differences in the fauna 



* It will be iutoresting to note wliat result, if any, follows the seriou.s clcstriicti(jn ef vcgeta- 

 tiou that is now going on in all the present battle areas. 



