PROOEEDINGS OF SOCIETIES. 23 



Edinburgh for many years before his removal to the Chair of Natural History in Aberdeen. 

 Here he filled in succession, and with groat credit, the offices of Assistant-Keeper of the College 

 Museum, and of Conservator of the Museum of the Eoyal College of Surgeons. He was a most 

 laborious student and exact ob.'^erver. His published works prove how well acquainted he was 

 with a large range of subjects in Natural History. Doubtless, had his life been prolonged, he 

 would have done much to extend the science and to foster a taste for the study of Natural History." 

 Mr. Hugh Miller then read a paper on the ancient Grauwackc Hocks of Scotland, with 

 a historical sketch of the progress of geologic discovery among them during the last sLxty years, 

 and a brief description of what is at present known regarding their place, character, and 

 organisms. The paper was illustrated with a fine collection of See to- Silurian fossils. On tlio 

 motion of Professor Fleming, the thanks of the Society were unanimously voted to Mr. Miller 

 for his valuable and interesting paper. 



Natural History Society of Glasgow. — The ordinary monthly meeting of this Society was held 

 in the Library of Anderson's University, on the evening of Tuesday, the 5th. of October, when 

 there was a full attendance of members.— Thomas Gray, Esq., Vice-President, in tlic Chair. 



Specimens of the Stormy Petrel from lona, were exhibited by Egbert Gray, Esq., who also 

 read a very interesting letter from Henry D. Graham, Esq., descriptive of the habits of that 

 bird. 



. A paper was read by Mr. John Gray, on the local distribution of the British Sphingida;, 

 with special reference to the changes caused by cultivation, and the anomalies thereby presented 

 in the geographical range of the various species. He concluded his paper by a general review 

 of the similarity and dissimilarity, where such existed, in their British and continental habitats, 

 with some remarks on the utility of a proper understanding of the geographical distribution of 

 the Lcpidoptera, and its bearings on collections of local fauna. 



The following recent observations on the House Fly were communicated by James Napier, 

 EsQ.:- 



On the day of the last severe thunder storm in August last, I observed, immediately after the 

 storm had passed, my paij^our window facing the storm literally studded with dead flies adhering 

 to the glass; beside each fly was a small' opaque cloud, composed of a white gummy matter 

 that appeared to have been ejected by the fly, and that very recently, from its being soft. That 

 it had been simultaneous with the death of the insect, I think evident, from the wings and 

 feet in most cases being covered with it in such quantity as to make it impossible for the 

 insect to fly or walk. In all cases the insect was adhei-ing to the glass by this gummy sub- 

 stance, some by the feet, the wings, and the mouth or sucker of the proboscis; in every 

 instance this sucker was at its full expansion, as if blowing out; and in two cases, out of the 

 few examined, the proboscis was ruptured or burst in the side. 



Whether the death of these insects took place during the thunder storm, or in consequence 

 of it, I cannot affinn ; but they had all died within the space of a few hours, and that insects 

 are affected by sudden or great atmospheric changes can hardly be doubted. I have spoken 

 with several persons who observed the same sudden mortality among the flies about the same 

 time, and also the invariable spot of dirt, as it was commonly called, contiguous to each insect. 



In connexion mth this gummy matter, I may add a few observations first made some years 

 ago. About the latter end of summer, (the month of August,) flies will often be observed 

 standing perfectly motionless often for a period of fifteen or twenty minutes; examining them 

 during these moods by a lens, it will be observed that they are not entirely idle, but are 

 blowing out from their proboscis a fluid, which they hold at the mouth of their trunk as a 

 globule, often as large as the head of a small pin. This globule the insect sucks in and blows 

 out every few seconds, oocasionally drawing in the proboscis and again throwing it out, evidently 

 with great enjoyment. These drops of fluid often fall on the place where it stands, and form 

 gray-coloured round spots, which soon get dark and constitute a great portion of that termed 

 Jly dirt. I have seen several of these drops fall in a few minutes, exciting some apprehensions 

 at the consequences were it continued. May not this account for the fact, that dead flies are 

 always dry and empty ? The fluid, by reflected light, is of a cream-colour, viscid and gummy, 

 and occasionally little specks of air and dust are seen in it, but no revolving motion has been 

 observed. 



