SOCIETIES. 217 



to stabilis, and, although its larva and structure are truly Tamiocampid, 

 yet it has a remarkable superficial resemblance to the genus Noctua. 

 Mimosa (probably the most specialised species) is, at the same time, 

 the most aberrant member of the genus ; its larva is Tccniocatupid, and 

 its relations are with s/a/>ilis and cruda, but having no very close con- 

 nection, apparently, with either. The groups into which it appears 

 advisable to divide the genus for the purpose of comparison are : (i). 

 Leucographa -A-wdi riibricflsa ; (2). Miindn, instabilis, opima, gothica ; (3). 

 Populeti, gracilis, stabilis, cruda ; (4). Miniosa. The relation of these 

 groups to each other was fully discussed. 



II. Variation. Taking the genus as a whole, we find very closely 

 allied species, and should naturally look for parallel ranges of variation. 

 The " origin of species " points out that this should be so, for if a slight 

 modification and gradual development, owing to environment, etc., 

 bring about specific distinction, it follows, that reversion and natural 

 selection generally, will aid in the development of somewhat similar 

 forms under similar conditions The general variation was then con- 

 sidered under the following heads : — ( i ). Colour variation ; (2). Variations 

 in size, shape and position of stigmata; (3). Modifications of transverse 

 lines (basal line, shade between stigmata, angulated dotted (or wavy) 

 line beyond the reniform, and line parallel to hind margin; (4). Develop- 

 ment of dots and wedge-shaped marks, parallel to hind margin. All 

 these points were fully dealt with and illustrated by the various species, 

 T. instabilis, as the most variable member of the group, being repeatedly 

 taken as the basis on which the various arguments were worked out. 

 Mr. Tutt then made a few remarks as to the effects of "Natural Selec- 

 tion " on the variation of the same species in different localities. Of the 

 specimens of instabilis sent from Hereford, almost 50 per cent, were 

 dark, whilst from Forres, of those sent not more than 2 per cent, were 

 dark ; but these specimens were picked, and probably the percentage 

 given might be erroneous and misleading, as Mr. Tutt had worked 

 neither district. The large amount of material needed for working up 

 a subject like this fully, Mr. Tutt suggested, prevented many from taking 

 up the study, and the material was not at hand in the Museum at 

 South Kensington. The comparative inaccessibility of the scientific 

 collection to ordinary workers was much to be deplored, although Mr. 

 Tutt did not think the curators of the entomological department were 

 in any way responsible. He could not help thinking that the collections 

 might be made of more real service to British entomologists than they 

 are at the present time. Mr. Tutt concluded by acknowledging his 

 great indebtedness for material and suggestions to Dr. Chapman, who 

 had supplied him most generously with specimens to work out the 

 variation. 



Mr. Fenn stated that from his experience of T. miniosa, he considered 

 it closely allied to cruda, and that its resting position in nature, was 

 very similar to that species. It also varied considerably. Dr. Euckell 

 had observed that the T/ENiocampid.^^ all emerged at about 10 o'clock 

 a.m. Mr. Machin, Mr. C. G. Barrett, and others also took part in the 

 discussion. Replying to Mr. Lewcock with respect to neuration, Mr. 

 Tutt said it could not be depended on altogether, as it was unstable 

 and very unreliable. Votes of thanks to Mr. Tutt and the country 

 exhibitors were unanimously accorded. 



D 



