DISTRIBUTE INSECT VARIETY. 377 



At the present time we notice these seasonal varieties not 

 alone alternating in ordinary years, but witness their production 

 by fluctuation in annual temperature. Thus while many butterflies 

 and moths in the British Isles produce one or two annual 

 broodsj on certain years those ordinarily single brooded become 

 double brooded ; or those which are double brooded produce 

 three annual generations. Similarly we find increase in produc- 

 tion, accompanied with the generation o£ variety on proceeding 

 southward. Thus an unusual third brood of Clouded Yellows, 

 developed in England in 1878, was noticed to be dwarfed, 

 with the black margin of the wings narrowed ; those of the 

 usual spring brood in Southern France, on the contrary, are large, 

 with broad black borders. A second extraordinary disclosure of 

 the Burnet Moth {Anthrocera jilipeyidulcc) in September presented 

 smaller crimson spots, with a tendency to coalesce. The South 

 African butterflies Callosicme Evarne and Keiskaimna, it is stated 

 by Mr. Mansel Weale, are varieties produced in successive 

 years. 



Poli/ommatus Agestis, a well-known little brown butterfly 

 with a marginal row of rich orange spots, common in the south 

 of England during May and August, when producing but a 

 single annual brood, appears in July as a variety [Artaxe7'xes) 

 that pi-esents the black spots on the wings replaced by white 

 ones, and which was for long on that account regarded by our 

 entomologists as a distinct species, the Pride of Scotland. Yet 

 the gradual selection of this " sport,^^ that suns itself on 

 Arthur^s Seat and the eastern lowlands, may be clearly traced as 

 we approach the north-eastern counties, where there occurs an 

 intermediate form [Salmacis) ; and we more than fancy we witness 

 its elimination during exceptional years in the south, as we 

 learn from the '' Manual of British Butterflies and Moths " 

 that a singular variety was captured near Brighton during the 

 July of 1857 by Mr. Cooke, which showed the characteristic 

 white spot on the fore-wing. That it is not an aberration due to 

 food, as Professor Zeller once surmised, has been triumphantly 

 proved by Mr. Buckler, who succeeded in rearing caterpillars 

 from Hartlepool on the rock rose, that disclosed butterflies 

 pictured as the three varieties above, while conjointly he has 

 discovered the northern larvse merely differ from the southern in 



