M. Peters on the Light of Lainpi/ris Italica. 31 



the animal has traversed a space of one or two feet, but that wliile it 

 traverses that space, it emits a permanent light, which produces a band 

 of very brilliant fire. When the animal is in repose, I have often counted 

 from 80 to 100 luminous discharges in a minute ; it then remains for a 

 pretty long time without phosphorescence. There always remains a 

 slight luminosity, which is never wholly extinguished, at the point of 

 the body from which the luminous discharges are made. The luminous 

 region, in the male, extends along the under side of the belly, between 

 the fifth segment (from the anal extremity) and the penultimate one, 

 with very nearly an equal degree of intensity; but, in the female, it 

 scarcely occupies more than the fifth segment, and is even concentrated 

 at its sides. If we observe this phosphorescent organ with a glass while 

 it is emitting sparks, we notice in it a tremulous or undulatory move- 

 ment, as when molecules are in motion. If we remove the luminous 

 organs, and expose them to the air free, they shine with the same in- 

 tensity as in the living animal, until their light becomes gradually ex- 

 tinguished. If they be rubbed against some body, the place shines for 

 an instant with a greenish light, which can be made to reappear after 

 becoming extinct by pouring a little water upon it. When the belly of 

 the insect is opened, and the adjacent portions of the intestines removed 

 without injuring the phosphoric organs, the latter continue to shine as 

 before, but this luminosity ceases on the instant that the head is separated 

 from the trunk. 



According to these observations, are we not permitted to conclude, — 

 1st, that it is not necessary that a globule of air should proceed from the 

 head in order to produce these sparks, since the removal of the anterior 

 and most essential parts of the trunk exercises no influence on the phos- 

 phorescence ; 2d, Since the removal of the head immediately causes the 

 luminosit}'^ to disappear, is this not a proof that the phenomenon depends 

 on the will of the animal .'' 



I believe it is quite unnecessary, continues M. Peters, to refute in this 

 place the opinion of some observers, such as Roda and Murray, who af- 

 firm that many Coleoptera enjoy the same faculty of absorbing the solar 

 light, and emitting it again at pleasure, since the Lampyris shines in the 

 night even when it has been protected all the day from the solar light. 

 Nay more, I kept some individuals in darkness for upwards of eight 

 'lys, and they shone with as much intensity and splendour as before. 



In order to study the organa lucifera more at my leisure, I carefully 

 removed all the dorsal part of the skeleton, and exposed the intestines, 

 whicli were filled with air. In the females, the ovaries immediately ap- 

 pear, as they fill a large portion of the interior of the body ; wliile, in the 

 males, we notice behind the posterior canals the deferential and semeni- 

 ferous canals rolled upon themselves. Neither the bodies nor fluids con- 

 tained in these canals possess luminous properties ; and these two organs, 

 very distinct from those of the phosphorescence throughout their whole 



