124 [May. 



collection. Mr. McLaohlan rcinarlved that he thought the material exhibited 

 preferable to artichoke pith, which had been used for a similar purpose. Mr. Goss 

 exhibited a species of a Mantid, Pseudocreohotra Wahlbergi, Still, received from 

 Captain Montgomery, J. P., of Mid-Ilovu, Natal. He said he was indebted to 

 Mr. Champion for determining the species. Mr. Frederick A. A. Skuse communi- 

 cated a paper, entitled, " On a Colour variety of Heteronympha Merope, Fab., from 

 New South Wales," and sent coloured drawings of the typical form and the variety 

 for exhibition. Mr. Oswald H. Latter read a paper, entitled, " Further Notes on the 

 Secretion of Potassium Hydroxide by Dicranura vinula (imago) and similar 

 Phenomena in other Lepidoptera." The paper was illustrated by the oxy-hydrogen 

 lantern. Professor Meldola congratulated Mr. Latter on the thorough way in which 

 he had worked out his experiments, and said that in view of the small quantity of 

 material at his disposal the concordance in the results was remarkable. He added 

 that Mr. Latter had, for the first time, proved the secretion of free potassium 

 hydroxide in the animal kingdom. Mr. Blandford, Mr. Merrifield, Mr. Latter, and 

 Dr. Dixey continued the discussion. Mr. Merrifield read a paper, entitled, "The 

 results of Experiments made last Season on Vanessa C-album and Limenitis Sibylla." 

 This was illustrated by an exhibition of specimens of L. Sibylla, and a long series 

 of V. C-album, to show the effects of temperature in producing variation. Dr. 

 Dixey said that many of the forms of V. C-album exhibited reminded him 

 of V. C-aureum, a Chinese species, which he believed to be the oldest form of the 

 genus. He thought that much of the variation shown in this series of specimens 

 was due to atavism, and was not altogether attributable to the effect of temperature. 

 Mr. Barrett said he was interested to find that one of the forced forms of L. Sibylla 

 was similar to a specimen he had seen which had emerged from the pupa during a 

 thunderstorm. In connection with Mr. Merrifield's paper Mr. F. W. Frohawk 

 exhibited a series of 200 specimens of V. C-album bred from one female taken in 

 Herefordshire, in April, 1894. The series consisted of 105 males and 95 females, 

 and included 41 specimens of the light form, and 159 of the dark form. Professor 

 Meldola in proposing a vote of thanks to Mr. Merrifield, Dr. Dixey, and Mr. 

 Frohawk said that he was glad to think that the subject of Seasonal Dimorphism, which 

 had been first investigated systematically by Weismann, was receiving so much 

 attention in this country. He was of opinion that the results hitherto arrived at 

 were quite in harmony with Weismann's theory of reversion to the glacial form, 

 and all the evidence recently accumulated by the excellent observations of Mr. 

 Merrifield and others went to confirm this view as opposed to that of the direct 

 action of temperature as a modifying influence. Mr. Merrifield, Mr. Barrett, and 

 Dr. Dixey took part in the discussion which ensued. 



April 3rd, 1895. — The President in the Chair. 



Mr. C. J. Gahan exhibited two examples, male and female, of a rare Prionid 

 beetle, Chariea cyanea, Serville, which had been kindly sent to him for examination 

 by Mons. Ren^ Oberthiir; and stated that Lacordaire was mistaken with regard to 

 the sex of the specimen which he described in the " Genera des Coleopteres." He 

 pointed out that the elytra of the male were relatively much shorter than those of 

 the female ; and that the joints of the antennae from the third to the tenth were 

 biramose. Mr. Gahan also exhibited two species of the genus Decarthria, Hope, 



