ENTOMOLOGICAL INSTRUMENTS, &c. 543 
so completely as to cut off all communication with the 
atmosphere: he next placed the egg under a hen that 
had been sitting some days, who always kept it at the 
side of the nest, where it nevertheless derived benefit 
from her incubation. After the first day its interior 
was covered with vapour transpired by the chrysalises. 
Upon this Reaumur took the egg, and removing the 
linen plug it soon became dry again: he replaced it 
under the hen, and no vapour afterwards appeared. In 
about four days the first butterfly ever hatched under a 
hen made its appearance; it would probably have re- 
quired fourteen under ordinary circumstances. He tried 
the same experiment with some Dipterous pup; but the 
heat was too great for them, and they all perished+. 
Having properly prepared and set your specimens as 
above directed, the next step, when they have remained 
a sufficient time to be perfectly dry, is to place them in 
your cabinet. If you collect foreign insects as well as 
British, you may either preserve the latter in a separate 
cabinet, or keep both in the same, distmmguishing the in- 
digenous species by a particular mark. ‘The letter B in 
red ink, if the pin which transfixes the insect be run 
through it, or, in the case of Lepidoptera, placed before 
the specimen, would be a very distinct and sufficient in- 
dication of them. The drawers of your cabinets should 
be about 18 inches square, and from the glass to the 
corked bottom about an inch and a half in depth: but 
the larger Dynastide, as Megasoma Acteon, &c., will re- 
quire ¢wo inches. The frame of the glass should be rab- 
* Reaumur ii. 12—. 
