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 light, and were cer- 

 tainly not the larvae of Noctua 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 

 light 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 Orihoptera, as having been 

 once seen in a phosphorescent state. Others as- 

 sure us that the common " Daddy Longlegs," Ti- 

 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. 



