IQ THE ENTOMOLOGIST. 



It is, for instance, well known, from numerous examples in 

 the field, that imagines almost identical in facias may be specifi- 

 cally distinct (for instance, V. j^olycliloros-xanthomelas), while 

 other forms bearing not the slightest outward resemblance to 

 one another facially are representatives of one and the same 

 species. It would perhaps be difficult to find an entomologist 

 to-day who does not know the striking examples of merely facial 

 divergence afforded by extreme cases of seasonal dimorphism. 

 There is, for instance, the orange black-spotted A. Icvana and its 

 summer (heat) form, the black white-banded ab. j^rorsa. I shall 

 not forget the shock I got when, as a boy with primitive notions 

 of entomology and possessed of a wild desire to find as many 

 " different kinds " as possible for my collection, I was for the 

 first time shown the orange levana and the black prorsa together, 

 and then told that these two flies were of one and the same 

 " species," and lived and paired, the one in May, the other in 

 August ! What little entomology I had managed to tuck into my 

 brain got loose then, and when I had also seen several forms of 

 ab. porrima, intermediate between levana and prorsa, my notions 

 about butterflies went scattering to the winds. But I did not 

 give up ; I thought it worth trying to understand. So after- 

 wards I went about gathering in the bits again, and then already 

 I made a discovery. I found that I had lost one thing — evidently 

 for ever — and that was my delightfully irresponsible belief in 

 the " constancy" of "species." But, to use a metaphor which 

 was very popular in the biological battles which raged on the 

 Continent only lately, though " the bath with the child had been 

 overturned," I did manage to save the child. I only lost the 

 water, and that was well spilt. 



Ever since that time I have taken more delight in collecting 

 " shocks " than butterflies, and I have, for instance, risked the 

 "cabinet quality" of the best aberrations which I reared, in 

 order to study their appearance and flight in the open field. So 

 far I find that I lose or damage very few specimens, but that the 

 harvest in " shocks," even in this one instance, is very great and 

 very calming. At least, when one comes to realize that a single 

 apparently "constant" British species — Vanessa urticce, L. — is 

 evidently capable of producing a far greater number of difierent 

 and beautiful varieties than there are different species of Khopa- 

 locera in the whole of England, then one soon begins to take 

 " shocks " naturally ; and, after all, it is only " thought fixed by 

 custom " that could prevent one from thus taking any un- 



from the wild larvaj (among different broods to prevent later stagnation) by 

 a moderate temperature experiment, and then to breed from these forms, 

 relying on the cumulative effects of hereditism for further variation. In 

 the case of, for instance, var. varleyata, it should not be distinguishable 

 whether the specimen was produced by temperature effects or by hereditism. 

 When both factors combine, then the most extreme forms result. 



