PHOSPHORIC INSECTS. 155 
The same phenomenon appears to have been 
seen in the eyes of Bombyx cossus. 
A Russian naturalist, M. Gimmerthal, has ob- 
served that the caterpillars of Noctua occulta are 
luminous, and the observation was communicated 
to the Entomological Society of France by M. 
Audouin. Since then, M. Boisduval remarked 
one hot summer evening in the month of June, 
a quantity of caterpillars on the stems of grass. 
They shed a phosphorescent leht, and were cer- 
tainly not the larvee of Noctwa occulta, but rather 
those of Mamestra oleracea, though they seemed 
larger than usual. M. Boisduval believes that 
this luminous appearance was caused by disease, 
which would account for its not having been met 
with before upon this common species. 
If disease is capable of developing phosphoric 
hght in insects, which it certainly has been known 
to do in superior animals, as we shall see further, 
it will account for the fact that other insects be- 
sides those named have been seen, though rarely, 
in a luminous condition whilst alive. Thus, some 
authors speak of Grillus campestris, or Mole- 
cricket, among the Orthoptera, as having been 
once seen in a phosphorescent state. Others as- 
sure us that the common “ Daddy Longlegs,” T’- 
pula oleracea, was taken by a farmer who, seeing 
a light, knocked the luminous object down, and 
found it to be the insect just named. 
