PROCEEDINGS OF SOCIETIES. 93 



Captain Lang exhibited slides of arranged Polycystina and Dia- 

 toms ; not only for their intrinsic beauty, but to show his mode of 

 finishing off slides with a ring of tenacious white cement, on which 

 are described circles of red or white varnish. 



December 3rd. — The President read a paper " On the Eyes of 

 Insects." This was specially illustrated by a beautiful mount of a 

 section of the eye of the Death's-head Moth, prepared by Mr. H. 

 Mozeley, according to a method described in the October number of 

 the ' Quarterly Journal of Microscopical Science.' The paper de- 

 scribed the general structure of the compound eye of a typical insect ; 

 but more particularly presented a comparison between the diagrams 

 and descriptions in Dr. Hicks' work on the Honey Bee, and the ap- 

 pearances presented by the section. The possible difference between 

 the eye of an insect flying by day, and of a nocturnal insect, was 

 naturally referred to. The section seemed to afford no proof of the 

 corneal lens being made up of two conjoined plano-convex lenses, 

 though it was clearly seen to be doubly convex ; nor did the section 

 exhibit the narrow constriction behind that lens of which Dr. Hicks 

 speaks; nor did the conical lens, behind the corneal lens, appear 

 strictly to impinge upon the bulbous expansion of the optic nerve. 

 The writer was also disposed to regard the compound eyes of insects 

 as more microscopical in their action than telescopical, in which 

 latter aspect Dr. Hicks regarded them. 



January 7th, 1873. — Dr. Moses read a paper " On Picas auratus 

 and Picus tridactylus," two North American woodpeckers ; describing 

 also the structural adaptations of woodpeckers, generally, for their 

 mode of life. Specimens of the two somewhat rare birds were ex- 

 hibited. 



Captain Lang brought before the Society the first three numbers 

 of the ' Lens,' a new American Quarterly Journal of Microscopical 

 Science, calling the attention of the members to Professor H. L. Smith's 

 conspectus of the DiatomaceaB, and to Dr. Arnold's views (as con- 

 tained in the 3rd number) of the nature of the so-called " exclama- 

 tion-marks " of the Podura scale, which he regards as simply minute 

 epithelial scales on the surface of the principal scale, from which 

 they may be removed by electrical discharge, or by mechanical means. 

 He also exhibited slides of selected diatoms, from a gathering from 

 the Sandwich Islands, kindly sent to him by Professor H. L. Smith, 

 of Hobart College, Geneva, N.Y. 



Mr. Tatem reported an addition to the local fauna of some in- 

 terest, having recently found a male specimen of Salticus formicarius* 

 hybernating in an empty shell of Cyclostoma elegans, the mouth of 

 which it had closed with a compact web. This spider is admitted 

 to be British on the authority of Dr. Leach, who states that it is 

 found, though rarely, in Scotland. 



The Secretary exhibited a section of the human scalp, and also 

 sections of the stipes of exotic ferns, to show the differing arrange- 

 ments of the vascular tissue. 



* Blackwell's ' British .Spiders,' plate in., fig. 36, 



