40 • [July, 



stripes, has horny protuberances on all the segments, those on the third and fourth 

 segments being the longest ; each horn bears a brown-grey hair directed backwards. 

 Seen from above the larva has a pale dorsal stripe edged with a darker line, which is 

 composed of obliquely-placed dark streaks. 



The larva is sluggish, but when hungry or if disturbed, can crawl more quickly 

 than the larva of Agdistis tamaricis. When touched, the larva assumes a torpid, 

 motionless state. — E. Hering, Zoologisch. Museum, Konigl. Universitat, Berlin C. : 

 June 11th, 1888. 



On Melanism in Lepidoptera. — A casual observation this spring led me to form 

 a hypothesis as to the cause and meaning of melanism in Lepidoptera, which appear 

 to explain a considerable majority of the instances, and, at the same time, correlates 

 various facts in connection with it, that are otherwise of obscure import. I am not 

 sufficiently acquainted with the literature of the subject to know whether the same 

 hypothesis has been advanced before, but I do not happen to have met with it. 

 Melanism appears to be a western rather than a northern form of valuation ; to be 

 associated with a wet rather than with a cold climate ; and it has certainly been more 

 common of recent years, which may be attributed to the long succession (unprece- 

 dented) of wet seasons we have recently passed through. My observation was on 

 D.fagella. Twenty years ago this species afforded here an occasional dark or even 

 black var. Happening to meet with one of these, I searched carefully for two 

 seasons, but only got one black and two dark specimens. For the last year or two 

 (result of wet seasons) they have been fairly numerous. Visiting certain oak trees with 

 a lantern one night, lately, and the same observation might, occasion favouring, no 

 doubt have beeen made during the day, I found the dark var. quite numerous, 

 about one to three of the ordinary form. The point I wish to call attention 

 to is this, the afternoon had been showery, and one side of the trunks was very 

 wet, the other dry, the wot side was of a very dark colour, the dry portions 

 pale, and, as a consequence, the dark specimens of fagella were very conspicuous on 

 the dry portions, hardly visible on the wet, whilst with the ordinary form the 

 conditions were reversed, those on the wet bark were conspicuous, those on the dry 

 much less so. This observation appears to admit of generalising, because we know 

 that many trunks of trees, rooks, stones, mosses, &c, are much darker in colour when 

 wet, the change often being from pale grey to black, and that most of the species 

 that are subject to melanic variation are such as are in the habit of resting on such 

 objects ; natural selection would thus have abundant leverage to work with. I do 

 not know whether the melanism of the Lancashire and Yorkshire districts is acknow- 

 ledged to depend on the general griminess of all natural objects, trees, stones, &c., 

 but there is no doubt that this blackness of the resting places of insects is intensified 

 when they are wet. This hypothesis will not probably explain all cases of melanism, 

 but it seems to be widely applicable.— T. A. Chapman, Hereford : May, 1888. 



The South London Entomological and Natural History Society : 

 May 2teh, 1888.— T. E. Billups, Esq., F.E.S., President, in the Chair. 



Messrs. A. H. Japp, L. Stevens, and J. C. Matthews were elected members. •■ 

 Mr. Jiiger exhibited a larva of Nemeophila plantaginis, L., which he had found 

 dying, with a Oordius emerging from it. Mr. Helps showed Dianthozcia capsincola, 



