234 PROCEEDINGS OF SOCIETIES. 



error arising from the cause iudicated, and the more the appearance of 

 aperture was reduced by this system of measurement. 



Mr. Stephenson thought this might be accounted for by the 

 thickness of the foil used. 



Mr. Wenham said he set the stop so as to include the marginal 

 oblique rays, and by means of a diagram drawn on the black-board 

 showed that he really allowed a superfluously large opening. 



Mr, Slack then proposed a vote of thanks to Mr. Wenham for his 

 communication, which was carried imanimously. 



Mr. Mclntire read a short paper descriptive of the peculiar 

 structiire of the proboscis of a lepidopterous insect exhibited under a 

 microscope in the room, and of which drawings were also exhibited. 

 The paper will be found printed at p. 196. 



Mr. Wenham, in inviting remarks upon the paper, said that near 

 to his residence there was a quantity of the humming-bird moths, and 

 it occurred to him, whilst hovering over flowers they appeared able to 

 hold on as if by some anchoring process. 



Mr. Charles Stewart said that the appearance alluded to in the 

 case of the humming-bird hawk-moth was due to the remarkable 

 power which it had of balancing itself in the air (the same as that 

 possessed by some of the wasps and flies) rather than to any anchoring. 

 It would be very interesting to know what sjjecies it belonged to, and, 

 if a South African variety, perhaps it could be identified by com- 

 parison with the fine collection of insects from that part which ^vas to 

 be seen at the British Museum. It appeared probable that it belonged 

 to a race which had to live amongst peculiar flowers, and perhaps it 

 was unable to reach the bottom of the corolla, so as to obtain its food 

 in the usual way, and therefore had to take a short cut to it, like the 

 bees had to do in the case of such flowers as the jasmine and antirr- 

 hinum. An examination of these flowers would often show the 

 puncture made by the armed proboscis of the bee, who has in this 

 way got out the honey, as it were, by the back-door. He thought it 

 probable that the moth described by Mr. Mclntire might have to do 

 the same. 



A vote of thanks to Mr. Mclntire was carried unanimously. 



The meeting was then adjourned to May 6th. 



Scientific Evening, April 15th. 



The scientific evening, held on the 15th ult., was remarkable for 

 the exhibition of many objects of great interest, such as are seldom 

 seen at ordinary microscopical soirees, where it is found necessary to 

 consult popularity rather than the direct advancement of science. So 

 many instruments and preparations deserve special mention and de- 

 scription, that to do anything like justice to them would require far 

 more space than can now be devoted to that purpose. Amongst the 

 preparations we may, however, particularly distinguish a remarkable 

 series of sections of tumours exhibited by Messrs. R. and J. Beck, 

 which attracted the attention of the physiologists present. 



Mr. Ley's, illustrating the anatomy of Asopus luridiis, fully invited 

 the epithet " wonderful" freely bestowed upon them. 



Mr. IJow's collection of geological photographs for the lantern 



