Microscopical Society. 3151 



Also a description of a new species under the name of 



Lestis meatus, Smith. 



" Female, (7 to 8 lines). Brassy green ; the pubescence on the face pale yellow ; tho- 

 rax punctured ; wings slightly fuscous ; pubescence at the apex of the abdomen 

 pale yellow. 



"Male, (7 to 8 lines). Brassy; face as in L. bombylans, but yellow, patches of pu- 

 bescence much more dense and bright yellow ; wings hyaline, slightly fuscous ; 

 all the legs fringed with bright yellow pubescence." 

 Mr. Smith also read a note ' On the Habits of Abispa, a solitary Australian Wasp.' 



—J. W. D. 



Proceedings of the Microscopical Society of London. 



April 16, 1851. — Dr. Arthur Faree, President, in the chair. 



Robert Semple Frere, Esq., Bransby Blake Cooper, Esq., and Wm. R. Morris, 

 Esq., were balloted for and duly elected Members of the Society. 



Dr. Asa Gray, Professor of Natural History in Harvard University, Cambridge, 

 Massachusetts, was balloted for and duly elected an Honorary Member of the Society. 



A paper by W. Ladd, Esq., ' On an Improved Adjustment for a Microscope,' was 

 read. After pointing out the disadvantages of the ordinary rack and. pinion move- 

 ment, Mr. Ladd described the improvement he had made, which consists of the sub- 

 stitution of a steel chain, known as a " fusee chain," for the rack, and a steel pin or 

 axis for the pinion. The ends of the chain are attached to the top and bottom of the 

 sliding bar which supports the body of the microscope, passing two or three times round 

 the steel pin or axis, which is furnished with a milled head. The motion thus produ- 

 ced is exceedingly smooth and even, and is not liable to the disarrangement on ac- 

 count of wear, which forms the greatest objection to the rack and pinion. A micro- 

 scope fitted up with this movement was afterwards exhibited to the meeting. 



A paper by Messrs. Hassall and Coppin, being a description of three species of 

 marine Zoophytes, was also read. These are three new species of corallines of the 

 genera Coppinia, Hassall (Zool. 2223), Sertularia, and Campanularia. They are re- 

 spectively named Coppinia mirabilis, Sertularia gracilis, and Campanularia serpens, 

 and are found on the English and Irish coasts. Detailed descriptions were given, 

 and drawings exhibited in illustration of the same. 



A third paper, being a translation of a letter from M. Nobert, giving a description 

 of a glass plate, having on it twelve systems of parallel lines, was read. These sys- 

 tems of lines were distinguished by the letters A, B, and C, to M, the latter being 

 the finest ; and the distances in each set were expressed with the utmost exactness in 

 Paris lines, as being, in system A, 0. //y 000375, to system M, which was the finest, 

 0. y "0001281. The other systems were of intermediate degrees of fineness. By using 

 this plate in a particular manner, fully described in the paper, the systems of lines from 

 A to G present an aerial spectrum of the prismatic colours, A being deep red and G a 

 deep violet ; and as no colour/appears in the remaining systems (from H to M), the 

 author considers that the distance of the lines in these systems is nearer than the length 



