LEPIDOPTERA COLLECTED IN 1917. 273 



al)le power which the species seems to possess for the oJBfspring to 

 produce the parent form, is quite sufficient to account for the 

 present position of ab. nigrana. 



Ab. alhonigrana is undoubtedly a development of the type 

 form of P. cristana ; ab. nigrocostana is, of course, a melanic 

 alboriificostana ; ab. meiiana and ab. jansoniana are obviously 

 derived from a member, or members, of the ab. striana group ; 

 ab. rufinigrana bears strong evidence that it is a melanic form 

 of the abs. chantana and spadiceana or forms closely allied to 

 them ; ab. ulotana is plainly derived from ab. desfontainiana ; 

 and ab. jlammeana from ab. consimiliana. The origin of ab. 

 atrana is more obscure, but I take it that it is a modern develop- 

 ment of abs. fulvovittayia, suhfalvovittana, or hentleyana, or all 

 of them. 



Ab. nigro-subrittana is obviously a melanic ab. punctana, or 

 ab. suhvittana. Of course there is no doubt that all these new 

 melanic forms are more or less dominant, and in addition to 

 obtaining recruits in each generation — once the melanic ten- 

 dency was established — from certain -of the old non-melanic 

 forms, each melanic form would tend to reproduce itself each 

 generation in increasing numbers. 



(To be continued.) 



LEPIDOPTERA COLLECTED IN 1917, MAINLY IN 

 GLOUCESTERSHIEE AND SUSSEX. 



By The Eev. J. W. Metcalfe, M.A., F.E.S. 



A RATHER bad break down in health during the trying winter 

 led to a three months' rest from work by doctor's orders. 

 Fortunately it was possible to arrange that my holiday should 

 cover the three best collecting months in the year — May, June, 

 and July — and, if it represented a rest from normal work, it 

 afforded a most acceptable opportunity for work of another kind 

 amongst the insects. The weather proved all that could be 

 desired, and the long spells of brilliant sunshine were only 

 broken by an occasional day's rain. 



As we all know, the winter prolonged itself far into the spring, 

 and the season on May 1st, when the fine weather really set in, 

 was undoubtedly three weeks behind-hand. So favourable, 

 however, were the ensuing weeks that by the beginning of June 

 insects, with the probable exception of those that feed up in 

 the early spring, were fully up to time, if not ahead of it. 

 Undoubtedly the season now going over has been, from the 

 collector's point of view, one of the best experienced for many 

 years ; and equally beyond doubt this fact is due to the bitterly 

 cold and prolonged winter. Not only must the cold weather 



