CLIMATIC VARIETIES 173 



destroyed. Many species are continually throwing off indi- 

 viduals which feed up fast 12 and emerge at once if the temperature 

 permits, and I imagine a species of Satyrid wholly or largely 

 represented by such individuals could scarcely survive in a 

 country which had a hard winter. For such a climate some 

 definite periodicity in the appearance of the broods may well be 

 indispensable. But assuming that egeria is cut off from cold 

 climates for such a reason, there is nothing yet to connect these 

 habits with the fulvous colour, and until breeding can be carried 

 out on a satisfactory scale there is no more to be said. 



From time to time records appear of individual specimens 

 more or less fulvous being caught in southern England, especially 

 in the New Forest. 13 It would be interesting to know what 

 offspring such individuals might produce. From the evidence 

 now given some notion both of the strength and the weakness 

 of the case considered as one of continuous climatic variation 

 can be formed. I know no other equally satisfactory. Whether 

 or not definite mixture of the intermediates with either of the 

 extremes will be proved to occur, the case differs materially from 

 those considered in the last chapter in the fact that at all events 

 there is no general overlapping of forms. In a species so little 

 given to wandering, overlapping could indeed scarcely be expected 

 to occur. It is this circumstance which makes the species 

 preeminently suitable as a subject for the study of climatic 

 influences, and I trust that entomologists with the right oppor- 

 tunities may be disposed to explore the facts further. 



Just as many species, like egeria, have varieties which can 

 be regarded as adapted to northern and southern regions, so 

 there are also several which have lowland and Alpine forms quite 

 distinct from each other. Every such case presents an example 

 of the problem we have been considering. As the collector 

 passes from the plains to the Alpine region, how will he find the 



12 Some most unlikely species do this. I once had a larva of Parnassius delius, 

 found at about 5,500 feet, which emerged late in the autumn (in October I believe), 

 a season at which it must have perished in its own country. 



13 See, for examples, Barrett, G. C, Lepidoptera of the Brit. Islands, I, 1893, 

 p 229; also Grover, W., Ent. Rec, IX, 1897, p. 314; Williams, H., Proc. Ent.Soc, 

 1898, who reared several specimens from the New Forest which would pass for 

 Bretons, though the rest of the family were true egerides. 



