HALF-AN-HOUR AT THE MICROSCOPE. 113 



are most likely to be met with in the south of London, are 

 A?idrena atriceps^ A. Trimmerana^ A. nigroce?iea, and A. Afzeliella. 

 The first three are very generally distributed and often abundant. 



EXPLANATION OF PLATE XIII. 



Fig. 1. — Stylops, (?sp.) male. 

 2. — Ditto, female. 



3. — Ditto, in its early larval state. 



All very much magnified. 





1balf*=an:^1bour at tbe fiDicroecope, 



Mttb /IIM\ Xlutfeu Mest, ^.%S., ff.lR./llb^S., etc 



sting of Scorpion.— Just at the outlet of the canal for the 

 poison, some small masses are present. With the highest avail- 

 able power and the polariscope, my friend, A. Nicholson, proved 

 to my satisfaction that these were crystals of Oxalic, or (as I 

 think) some Isomeric Acid, infinitely more deadly. Correlating 

 Lewis G. Mills's observations of crystals at the outlet of the 

 poison-canal in the falces of a Spider found by him, I think it 

 not unlikely that in hot, dry seasons, similar crystals might be 

 found in the stings of Nettles, of Loasce, and other urticating 

 plants. Who of our members will undertake such an inquiry ? 

 To obtain the requisite knowledge of what to examine, botanical 

 text-books would, of course, have to be consulted. The fangs of 

 Poison-serpents might be expected to yield similar crystals — ano- 

 ther most interesting inquiry for those who will, to take up. 



Naphthaline. — The contributor would oblige more than one 

 country member by a few particulars as to what this substance is, 

 whence obtained, and where to be procured. It is considered by 

 Prof. Williamson, of Manchester, to furnish the very best of all 

 substances for imbedding delicate microscopic subjects in, pre- 

 vious to cutting sections. The crystals are both pretty and 

 interesting. The li?ies of crystalline deposit seen in parts are due 

 to minute scratches on the surface of the 2;lass. How delicate 



