3180 Microscopical Society. — British Entomologists. 



the help of English entomologists, in furnishing him with specimens of diurnal Lepi- 

 doptera, stating that it would be sufficient for his purpose if there were but an upper 

 and an under wing free from damage. 



Herr Helfrick, of Berlin, had also intimated his desire to exchange with any of the 

 Members, specimens of the larger European Lepidoptera for English species. 



It was announced that Part 5, Vol. i. n. s. of the Society's 'Transactions,' was 

 ready for delivery. — J. W. D. 



Proceedings of the Microscopical Society of London. 



May 21, 1851. — George Shadbolt, Esq., in the chair. 



Thomas Chamberlain, Esq., Jabez Hogg, Esq., John Ladds, Esq., William Ladd, 

 Esq., Joseph Taylor, Esq., and George Field, Esq., were balloted for and duly elected 

 Members of the Society. 



A paper by George Shadbolt, Esq., On the Sporangia of some of the Filamentous 

 Fresh-water Algae, was read. 



After stating that the facts to which he wished to direct the attention of the Society, 

 were, if not hitherto entirely unknown, at any rate, not made public, so far as he had 

 been able to ascertain, the author proceeded to describe that he bad ascertained that 

 the sporangia of Zygnema quadratum, Z. varians, and of another of the Algae, proba- 

 bly a species of Tyndaridea, undergo a gradual change of form, and finally assume a 

 stellate character, precisely similar in appearance to the so-called Xanthidia found in 

 sections of flint, and analogous to the stellate sporangia of the allied family of the Des- 

 midieae. That consequently the figures of the sporangia of the above-named species, 

 as given in Hassall's ' British Fresh-water Algae,' though perfectly correct as far as 

 they go, are only figures of the fruit in a transition state. The author suggests, that 

 as Zygnema quadratum is a species in which conjugation occurs between contiguous 

 cells of the same frond, while, on the contrary, in Zygnema varians it takes place be- 

 tween those of different filaments, in all probability a similar change to that described 

 ensues with regard to the sporangia of all the species in both the subdivisions of the 

 genus, and possibly in most, if not in all, of the family. — /. W. 



Proceedings of the Society of British Entomologists. 



The June meeting of the above Society was held at the Society's rooms, 10, Foun- 

 tain Place, City Road, on the 3rd instant: Mr. Harding, President, in the chair. 



The following insects were exhibited: — Trochilium culiciforme and Acasis viretata. 



The President remarked that this had been the most backward season he ever re- 

 membered ; he had taken many of the early Lepidopterous insects as late as the 20th 

 of May : for example, he had taken Taeniocampa gothica, T. stabilis, and T. gracilis, 

 as well as Anticlea badiata, as fine as if they had but just emerged from the chrysalis, 

 three months after their usual time of appearance ; and many Diptera, which usually 

 appear at the beginning of the month, did not make their appearance until the 28th. 



Some seed-heads of Centaurea nigra were exhibited, which contained the chrysalis 



