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THK KNTOaiOLOGIST S RECORD. 



a strong basis, but, unfortunately, neither of these hypotheses holds 

 good, and I cannot, for the moment, call to mind any of the apterous 

 winter moths that has not several larval foodplants. Take the case 

 of Cheimatohia bniinata. Whether its true food plant was scented or 

 not in winter, such an universal feeder could hardly go wrong wherever 

 it might happen to oviposit. Take Ny>i^ia lahponaria again. Why, 

 with the miles and miles of nothing but heather and birch in its 

 Scotch haunts, how could the females, even with the largest and 

 weakest of wings fail to oviposit near its proper larval food ? Or take 

 N. zonaria. When it emerges the sallows are in full blossom. 

 and we all know how attractive they are to moths. Surely it is hard 

 to credit that the scentlessness of foodplant would, in this case, account 

 for winglessness in the females. On the other hand, if Dr. Chapman's 

 theory be correct, does it not seem that nature has paid an extravagant 

 price for the object which she presumes she has gained by depriving 

 certain insects of wing power? With Cheimatohia it is true, there is 

 the compensation of increased pedal activity ; but with Nyssia there is 

 no such compensation and, as a result, apparently, both A', zonaria and 

 N. lapponaria are excessively local, though, on the other hand, I'/iiyalia 

 pedaria {pilomria) and ^V. hispidana seem less att'ected and are coiumon 

 in most places. That the subject is full of intei-est and will bear deep 

 investigation is evident, though I doubt if Dr. Chapman has yet hit on 

 the satisfactory explanation. — Percy C. Reid, F.E.S., Feering Bury, 

 Kelvedon. March 'lii.h, 1903. [This note being submitted to Dr. 

 Chapman he sends the following memorandum in reply : — " There is 

 perhaps one point in Mr. Reid's comments on my suggested explanation 

 of why winter moths have apterous females that ought to be referred to by 

 me, by way of reply, since it may have resulted from some obscurity 

 in my original statements. 1 had often, of course, wondered why 

 • these moths were apterous, and felt dissatisfied with any explanation 1 

 met with, but had seen no way of investigating the subject and for 

 all practical purposes the problem might not have existed so far as 1 

 was concerned. It was only after having familiarised myself with the 

 Psychids and Orgyias, and concluded that there could be little, if any, 

 doubt that apterousness with them was a provision to prevent any 

 mistake as to where the eggs should be laid, that i thought some 

 similar principle might be found to explain the apterousness of 

 winter moths, and began to search for some way in which it would 

 apply, and imagined that the scentlessness of plants, when enjoying 

 their winter sleep, supplied the conditions that made the same explana- 

 tion applicable. It seems, therefore, desirable to point out that Mr. 

 Reid is in error in saying that I abandon my theory in the case of 

 Psychids and Orgyias, since, on the contrary, what 1 do, is to bring 

 the winter moths {mutatis mutandis) within the Psychid-Orgyia 

 explanation. Mr. Reid's other criticisms do not seem of much 

 moment, and, if nothing more damaging can be advanced, make 

 me believe that my view of the matter is on stronger ground than I 

 had supposed. I cannot see how a larva having one or several 

 foodplants affects the matter. From the point of view of the 

 ovipositing moth it only nuikes the foodplant a little more or less 

 abundant. Or, again, is sallow " the " foodplant of Nt/ssia zonaria ? Why 

 should this price paid by Nature to secure the advantage of havmg 

 the proper position of the eggs made sure be regarded as extravagant, 



