ENQUIRY iNtO TllK STliUGGLK KOU KXISlKNClC iN AGLAtS tJHTlOE. 241 



can be definitely stated, and it must bo admitted there is room for 

 doubt. Pupic on smooth palings were annihilated, showing form to 

 be eilcctive. Watch was kept on several occasions to detect the 

 destroyers, but though pupiu disappeared during the watch in a 

 good many instances, nothing was seen except in one case, in 

 which a tit took a pupa. This points, perhaps, to mice rather 

 than birds being the more active destroyers, as Prof. Meldola sug- 

 gested, noting the experiences of many sugarers for moths, who 

 have found mice searching their sugared patches. It strikes us 

 as curious that golden pupae on nettles should have been the safest, 

 if this on analysis proves really to have boon the case. If this 

 were so, this should be the most usual situation for pupation, whereas 

 it is most exceptional, so much so that golden pupte found on nettles 

 are almost always stung by parasites, that is, only those remain and 

 pupate on the nettles that are too weak to attempt the journey of 20 to 

 100 yds., that all healthy larvae make to find a proper place in which 

 to suspend themselves. The experiments are most interesting, as an 

 attempt to give us a numerical measure of what we only know gener- 

 ally, or, in truth, only surmise. Their importance from this aspect 

 cannot be exaggerated, as leading the way, let us hope, to much more 

 work of the same kind. We shall look for the full analysis promised 

 us with much expectation, and even if the results in some aspects are 

 not very decisive, that is perhaps only to be expected in a fresh and 

 difficult field of research. 



Entomological Subjects discussed at the International Zoological 

 Congress, 1898. 



As supplementing the interesting notes on " The fourth Inter- 

 national Congress of Zoology," held at Cambridge during the week 

 August 22nd-27th, in our last issue, the following, dealing with other 

 entomological matters of interest, appear to be worthy of notice. 



EXPEKIMENTS IN THE CROSSING OF LOCAL RACES OK LEPn)0PTEi;A. 



Among the various objects of zoological interest placed in the zoologi- 

 cal laboratory were exhibits by Mr. Bateson, illustrating experiments 

 in the crossing of local varieties. Two species were especially inter- 

 esting, viz., I'aran/e ri/cria and I'it'iis najii. In the case of /'. cijcria, 

 the forms of the species occurring in western Europe were well illus- 

 trated by a large black-board, on which was sketched a map of 

 western Europe, and actual specimens were pinned on the board at 

 approximately their places of capture on the map. This arrangement 

 exhibits at once to the eye the distribution of /'. ojinia and var. aicriik's, 

 and did so completely for the purpose of the exhibit, though for 

 faunistic purposes a map taking in a larger area would no doubt be 

 necessary. (1) The southern form {(';n'iia) was shown to inhabit 

 Spain, western France, south of the Loire, and the lower Rhone 

 Valley, the actual localities being Gibraltar, Granada, Jaen, Biarritz, 

 Landes, Vienne, Poitiers, Avignon, Tarascon. (2) The middle form 

 (var. ijitcniiidia) occupied a zone round this, riz., the lower Loire 

 Valley, Brittany, ISavoy and the Riviera, the localities illustrated 

 being Avranches, Cancele, Balleroy, Gavrinis, Chambery, Nice. 

 (3) The northern and Alpine form {eijeriilfn) occupied England, Paris, 



