upon Luminous Animals. 277 
The circumstance of there being points, which give a more 
permanent light than the other parts of the luminous rings of 
the abdomen, lias been noticed before by the Comte G. de 
Eazoumouski. He states the number of these luminous points 
to vary from 2 to 5.* 
I must however remark, that I never saw more than two of 
these luminous points, which were always upon the last ring 
of the body, and that the figures which accompany the me- 
moir of the Comte de Razoumouski, bear scarcely any 
resemblance to the insect they are intended to represent, from 
which we may fairly suspect him of inaccuracy in other 
particulars. 
As far as my observation has extended, the small sacs of 
luminous substances are not found in any species of lampyris, 
except the glow worm of this country. Thunburg mentions 
that the lampyris japonica has two vesicles on the tail, which 
afiord light. 
The organs for the production of light in the genus elater, 
are situated in the corcelet; these likewise consist of a peculiar 
yellow substance, placed behind transparent parts of the shell, 
which suffer the natural colour of this substance to be seen 
through them in the day, and when illuminated, give passage 
to the light. 
On dissecting the organs of light in the elater noctilucus, I 
found that. there is a soft yellow substance, of an oval figure, 
lodged in the concavity of the yellow spots of the corcelet, 
which parts are particularly thin and transparent in this 
species. This substance is so remarkably close in its structure, 
that at first view it appears like an inorganic mass, but with 
* Mem. de la Soc. de Lausanne, Tom. ii. 
O o 
MDCCCX. 
