KOTES AND OBSERVATIONS. 53 



.1847 has never been satisfactorily explained, and nO cycle, I am told, 

 has yet restored Aporia cratagi to its haunts of sixty years ago, 

 excepting Kent, where it may have been reintroduced from the Con- 

 tinent. Nor would the reappearance of C. dispar at all astonish me, 

 since attempts have been made for some time to establish Dutch 

 specimens said to present no difference to the aborigines. 



Turning to moths, Triijonopliora flavimea [empyrea) has apparently 

 disappeared from its Sussex haunts for years. Other examples of 

 total and inexplicable disappearances could be given, but I refrain 

 from treading further on what may be delicate ground. I will only 

 say, as having some bearing on this part of the subject, that all my 

 attempts at transplanting lepidopterous insects have been total 

 failures, although every care was taken to select what appeared to be 

 identical habitats. 



So much for what seems inexplicable. But there are insect 

 disappearances which are as permanent as the examples given, and 

 which admit of explanation. In my experience I have known a colony 

 of Plebeius cegon exterminated in a small, isolated area in a few hours 

 by over-collecting. Some years ago Pieris napi was abundant near 

 Chester, the females especially being heavily charged with black. 

 Next year there were none, farming operations having destroyed the 

 food-plants. CcBuonympha tiphon (davus) vanished from a spot 

 which was entirely changed by a growth of trees. Another limited 

 locality for this butterfly was reclaimed and cultivated, and, of course, 

 tiphon disappeared. 



We now reach the fact that " all species are commoner one year 

 than another." In considering this part of the subject the year 1916 

 stands out as a dismal illustration, and, as far as my observation in 

 this district was concerned, I agree with Colonel Eattray that it was 

 a disastrous year for the collector. Pieris brassiccB and P. rap<B 

 appeared in their usual numbers (a few years ago P. hrassicce almost 

 disappeared), but these species struck me as being the only ones 

 whose numbers were normal. In September, 1915, Pyrameis 

 atalanta could be seen commonly enough in the park feeding on the 

 big daisy-like flowers of Senecio clivorum, or on the long blue flower- 

 spikes of Buddleia albiflora. So engrossed were they that I 

 frequently picked them off" with finger and thumb when they closed 

 their wings, and then letting them fiy again. In 1916 I did not see 

 one or even a larva. A few Vanessa io (absent in 1915, and rare for 

 some years back) took their place ; colonies of io caterpillars were 

 seen last June on nettles outside the town two miles away. 



A very unusual feature in the past season was the almost total 

 disappearance of A. urticce. Probably the inclement spring — con- 

 tinued well into June— had much to do with diminished numbers, 

 but the wandering habits of the butterflies just mentioned will 

 account for districts being sometimes missed in the distribution of 

 species. 



I observed a similar falling off in the number of moths in 1916 

 Ivy was not attacked by larvte of Boarmia rhomboidaria, Jerusalem 

 artichoke, and other plants by Arctia lubriccpeda, or loganberry by 

 Odontopera bidentata, and the numbers of perfect insects of these 

 species was correspondingly small. (It is remarka-ble how different 



