INSECTS. 475 



might easily and artificially be produced by straining a 

 portion of Brussels lace with hexagonal meshes over a 

 small hemisphere of ground glass. That this gives a toler- 

 ably fair idea of the intricate carving on the exterior, may 

 be further shown from the fact, that delicate and beautiful 

 casts in collodion may be procured from the surface, by 

 giving this three or four coats with a camel-hair pencil. 

 When dry, it is peeled off in thin flakes, upon which the 

 impressions are left so distinct, that their hexagonal form 

 can be discovered with a Coddington lens. This experi- 

 ment will be found useful in examining the configuration 

 of the facets of the hard and unyielding eyes of many of 

 the Coleoptera, in which the reticulations become either 

 distorted by corrugation, or broken by the pressure re- 

 quired to flatten them. It will be observed also, that by 

 this method, perfect casts can be obtained without any dis- 

 section whatever ; and 

 that these artificial exu- 

 vice for such th ey really 

 are become available 

 for microscopic investi- 

 gations, obviating the 

 necessity for a more 

 lengthened or laborious 

 preparation. The dis- 

 section of the cornea of 

 an insect's eye is by no F5g 236 



means easy. I have USed A, is a section of the eye of Mrlolonthavulgans 



o-pnprallv a <?mflll rm'r Cockchafer - B, a portion more highly mag- 

 gen ,rany a sman pair nified( showinf? the facets of the cornea , and its 



of SCisSOrS, With Well- transparent pyramids, surrounded with pig- 

 j. , j -, . , , ment. At A they all meet to form the optic 



adjusted and pointed nerve. 



extremities, and a camel-hair pencil, having a portion 

 of the hairs cut off at the end, which is thereby flat- 

 tened. The extremity of the cedar handle should'be cut 

 to a fine point, so that the brush may be the more easily 

 revolved between the finger and thumb; and the coloured 

 pigment on the interior may be scrubbed off by this simple 

 process. A brush thus prepared, and slightly moistened, 

 forms, as far as my experience goes, by far the best forceps 

 for manipulating these objects preparatory to mounting; 

 as, if only touched with any hard-pointed substance, they 



