PROCEEDINGS OP SOCIETIES. 279 



disposed in tlie form of beads, the appearances were a confirmation of 

 his own views on the matter of dispute. 



Mr. Hogg said the effects produced by Dr. Maddox were obtained 

 while the scales were in a torrefied condition. He (Mr. Hogg) had 

 also made experiments on the torrefied scales in the way proposed by 

 Mr. Wenham. The pigment seemed to run up the longitudinal 

 markings, giving a continuous effect, and under the ^V^^ immersion 

 lens, which showed them remarkably well, the notes of exclamation ! ! 

 were quite destroyed. No doubt the structural characteristics of 

 scales can be better studied in the larger si^ecies of the T.epidoptera, 

 as Dr. Maddox has pointed out in his valuable paper, when it is found 

 that they are not inserted " as tiles are in the roof of a house," but 

 are as much of an outgrowth of the dermal structures as are the hairs 

 of animals or the feathers of birds. Their bulbous extremities, being 

 firmly imbedded in the membranous wing, and filled with an albu- 

 minous or fatty colouring matter, this flows up the shaft, permeates 

 the tubules, or series of longitudinal folds, for the i^urjiose of nou- 

 rishing the scales, in precisely the same manner as the epidermal 

 structures covering animal bodies derive nom*ishment and are main- 

 tained in health. These closely-placed tubules filled with colouring 

 matter give the iridescent hues and colour so much admired in the 

 wings of Lepidoptera : as soon as death takes j)lace the pigment 

 shrivels ujj, leaving certain interspaces, which, when viewed above 

 transverse or irregular markings in the basement membrane, height- 

 ened by an oblique pencil of light, j)roduce false appearances of " rows 

 of beads." The beautiful drawings sent with Dr. Maddox's paper 

 show this to be the explanation of the structui'e of scales, while his 

 photographs, and also those of Dr. Woodward, prove that pseudo-beads 

 can as easily be produced by artificial means. 



Mr. Slack said, that Mr. Hogg's experiments on Lejiidopterous 

 scales showed that their structure was analogous to that of the feathers 

 of birds. He had noticed the bulbs described by Mr. Hogg, and he 

 apprehended that the pigment matter was either conveyed through 

 the quill or by exudation from the membrane ; and as it shrunk it 

 tended to divide into portions more or less beaded. Mr. Hogg's 

 experiments seemed to him to lead to conclusions which he (Mr. 

 Slack) had previously ventured to bring before the Society. 



A short communication was also read from Dr. Woodwai'd, en- 

 titled, " Additional Observations concerning the Podura Scale." 



Votes of thanks to Drs. Maddox and Woodward were then given. 



Mr. Lowne read a paper " On the so-called Suckers of Dytiscus 

 and the Pulvilli of Insects." 



Dr. Braithwaite said, the sucker of the Dytiscus was one of the 

 stock objects of a microscopical cabinet, and the functions it had been 

 supposed to perform had been copied from book to book, without any 

 test being applied as to the correctness of the descriptions. He had 

 no doubt that Mr. Lowne had that evening explained the true func- 

 tions, and he believed the explanation would carry conviction to the 

 minds of all who had heard it. He proposed that a vote of thanks 

 should be given to Mr. Lowne. 



