42 



Sil/c Felt produced by Satvrnia Puvonia-media. 



The President exhibited a specimen of silk produced at Vienna by the larvjB of 

 Salurnia Pavonia-media called in Germany " Schwartzdornspinner: '' he had received 

 it through the kindness of Herr Pretsch, from whom he learned that a series of most 

 interesting experiments were now in progress, the object being to obtain, from the la- 

 bours of this insect, a silken felt impervious to water. The larvae were confined sepa- 

 rately in polished receptacles, from which there was no escape, and which presented 

 no salient points that the cocoons could possibly be attached to, so that the whole 

 stock of silk was exhausted on the smooth surface, and could afterwards be removed 

 at pleasure. As the space allotted to each caterpillar was large and the stock of silk 

 small, the coating was very thin, as in the specimen exhibited, but the felt was readily 

 increased in substance by introducing a second and then a third larva, each of which 

 readily worked on the felt manufactured by its predecessor. He did not know to 

 what extent the experiments have hitherto been carried, but be believed they promised 

 perfect success. 



Note on Helobia impressa, Newman. 



The President read the following memorandum on Helobia impressa: — 



" I beg to exhibit some specimens of the insect which twenty-three years ago I 

 ventured to describe as distinct, under the name of Helobia impressa; and I do this, 

 not because I am now at all persuaded of its distinctness, but because the Rev. Mr. 

 Dawson appears to have been unacquainted with the insect at the time he was pre- 

 paring his invaluable ' Gcodephaga Britannica.' Helobia impressa was found at a 

 great altitude, on Ben Nevis and Ben Voirlich, by our friend Mr. Walker, and was 

 distributed by him amongst entomologists at the time : the specimen which I beg to 

 exhibit was captured by him. The difference between this and the common Welsh 

 insect, Helobia nivalis, is this : — in nivalis, one interspace of each elytron, the third 

 counting from the suture, is impressed with large deep foveas ; in impressa, two of these 

 interspaces, the third and Jifth, are thus impressed, giving the insect, at the first 

 glance, a very different appearance. After having read Mr. WoUaston's admirable re- 

 marks on the effects of isolation on species, I will not presume to dwell on the 

 importance of the character on which the species is founded, but I trust entomologists 

 will agree with me that the subject is worthy of investigation, and that this very 

 doubtful species ought at least to be separated from its Cambrian congeners as a named 

 and locally isolated variety." 



Improvements in Bee-hives. 



Mr. Downie exhibited a model of a wooden bee-hive, containing, as he explained, 

 several important improvements, proved by its use for the last three years. The im- 

 provements consisted of a moveable open floor with bars placed transversely to the 

 bars of the hive, sliding above the true floor of the hive, and affording great facility 

 for removing dead bees in winter without admitting cold air, a circumstance ou which 

 he laid much stress, as by the ordinary method of lifting the hive for the purpose of 

 clearing the floor the bees were injured by the reduced temperature in the hive; and 



