14d 



bodies, I boil tbem as rapidly as possible in about an ounce or more of benzole (adding 

 a little from time to time) in a water bath, whicb may be easily composed of a sauce- 

 pan containing water, in whicb is jdaced the covered jar containing ihe benzole and 

 the bodies. In this process that portion of benzoic which had previously soaked into 

 the interior of the slit body, having been brought into close relation with the grease so 

 as to dissolve it, is very readily volatilised ; bubbles of gas are seen to effervesce rapidly 

 from the body, currents of boiling benzole rush into and out of the slit body, and the 

 grease is literally washed out. This may be best observed by boiling a single body 

 with a drachm of benzole in a test-tube over a spirit lamp : but if the body be soaked, 

 and not boiled, the benzole in the intericn- of the slit body dissolves the fat ; but, while 

 drying, it percolates slowly through the substance of the body, and deposits again in 

 the interior nearly the whole of the grease previously dissolved, that portion only being 

 got rid of which, being on the exterior layers, is in immediate relation with a sur- 

 rounding stratum of benzole. The quicker the boiling, the more readily is the grease 

 vpashed out, but the greater the volatilisation of benzole. 



" The bodies are now removed from the hot liquid, washed with fresh benzole, 

 dried on blotting paper, and if exposed again to the action of heat will show no signs 

 of grease. It will be found necessary to test a single body from time to time, 

 the period necessary to extract all the grease varying according to the rapidity of 

 boiling, the strength and purity of the benzole, and the amount of grease in the 

 bodies. The bodies are finally attached each to its corresponding thorax with Canada 

 balsam, liquid glue or gum. 



" I think I may safely state that insects thus treated will never grease again. 



" This process may be performed in the winter months, when all greasy insects can 

 be cleaned together. It is economical in time and labour, and thorough in its action : 

 it interferes very little with the beauty of the insect. 



" That the body is the sole seat of grease is shown by taking a fresh-dried speci- 

 men of an insect liable to grease, as Nonagria Typhae. Disarticulating the body, 

 expose both it and the thorax and wings to the same amount of heat ; the body will 

 quickly discolour; the rest of the insect will remain unchanged. Bodies, therefore, 

 should be always heated, while the head, thorax and wings are as yet free from signs 

 of grease. If any doubt occurs as to the question of grease in an insect, its presence 

 is readily tested by the exhibition of the body on a cork placed about six inches dis- 

 tant from the fire. Only very greasy bodies need be boiled ; simple soaking will suffice 

 for slight cases. When bodies are very small the passage of a pin breaks them unless 

 soft with grease ; I therefore prefer to soak the whole insect as above described." 



Dr. Wallace subsequently boiled some greasy bodies of Nonagria Typhae in ben- 

 zole contained in a test-tube over a spirit-lamp, and exposed the bodies thus boiled, 

 and others which had not been subjected to the process, to the heat of the fire : the 

 former were unaffected by it, but the latter were rapidly discoloured and became soft. 



Mr. Westwood communicated some notes on the time of appearance, in the per- 

 fect state, of Acherontia Atropos, furnished by Mr. W. Groves. 



Mr. M'Lachlan read a paper intituled " Notes on the Genera Mystacides and 

 Setodes, in the second part of Kolenati's ' Genera et Species Trichopterorum,' with 

 reference to the Species described in the works of Messrs. Curtis and Stephens." 



