76 iMarch, 1911 



The President, in the course of his Address, after refeiTing to the losses by 

 death sxxstained dviring the preceding year, went on to speak of various events 

 of special interest to Entomologists, among these being the appointment of 

 Professor Meldola, F.R.S., as Herbert Spencer Lecturer, and Mr. Selwyn Image 

 as Slade Professor of Fine Art at Oxford ; the award of the Royal Society's 

 Darwin Medal to Mr. Roland Trimen, F.R.S. ; and the meeting of the first 

 International Congress of Entomology at Brussels. He then proceeded to deal 

 with certain problems of general biology on which special light had been 

 thrown by Entomological stvidy, notably the demonstration that permanent 

 races, differing from the parent stock, could be produced by artificial inter- 

 ference with the germ-plasm. This had been surmised from early experiments 

 of Weismann, followed by Standfuss and Fischer, and had now been placed 

 beyond doubt by the carefixl work of Tower in America, who had also shown 

 that the new form might stand in Mendelian relation with the stock from 

 which it sprang. Other topics touched upon in the Address were the psycho- 

 physical character of the material presented to the operation of natiu-al selec- 

 tion — a point particiilarly emphasized by Professor Mark Baldwin ; and, in 

 connection with this, the special interest attaching to the communities of the 

 social Hymenoptera, where the group, rather than the individual, appeared as 

 the unit of selection. — H. Rowland-Brown, Hon. Secretary. 



CHIBONOMID LARV.^ AND WATERSNAILS. 

 BY K. H. BARNARD. 



It is well known that the fountains at Trafalgar Square, London, 

 contain a small (the largest measure | inch), and thin-shelled 

 variety of Limnsea peregra. On March 4th, 1910, I brought home 

 in a pillbox two of these snails, and was surprised to find, on 

 reaching home, two larvae as well as the snails. They were 10 mm. 

 long, mottled with red and green, and proved, on examination, to 

 be Chironomid larvae. When placed in water they spun silken 

 tubes open at both ends. 



A large number of snails, of all sizes, each being examined to 

 see that no larvae were attached to the exterior, was then collected 

 and brought home in pillboxes. Larvae of various sizes were again 

 found amongst the snails ; three full-grown ones spun silken tubes 

 and changed to pupae on March 25th ; these, however, died. The 

 small larvae, although supplied with green Algx and kept with the 

 snails, soon died. 



Another lot of snails was collected, and brought home in water. 

 This time no larvae were found, but several of the snails shortly 

 died. These I examined, and in every case (9) a small larva. 



