244 [April, 



and subdorsal lines, the head becoming light brown and the plates 

 whitish. In July, although still apparently feeding, it has become 

 contracted to a mere lump, and is very sluggish, the ridges of the seg- 

 ments are then very distinct, and the pink dorsal and subdorsal lines 

 brighter. Up to this time it has burrowed in the stem of Artemisia 

 ahsyntJiium, at first making passages under the bark, but soon boring 

 into the wood and eating out its substance and pith, like that of 

 Epliestia cmeroseJIa, which it accompanies. But now it leaves its 

 burrow and wanders about, making special efforts to escape from con- 

 finement, and finally spins a slight white cocoon among rubbish, where 

 it changes to a chestnut-brown pupa, the moth emerging in August. 

 Its habits, therefore, are very different from those of the seed-feeding 

 species, which feed up so rapidly and remain so very long in the larva 

 state in cocoon. I have seen no indication of its ever feeding, even 

 in earliest infancy, in the Jlowers of the wormwood. 



Pembroke : 10th November, 1879. 



EXPERIMENTAL RESEARCHES ON THE PHOSPHORESCENCE OP 

 THE GLOW-WORM. 



BT M. JOUSSET DE BELLESME.* 



Electricity, the nervous fluid, and the insulation of vital forces, 

 have each, in turn, been evoked as causes of phosphorescence. Finally, 

 we stop at the consideration of the existence of a phosphorescent 

 matter emitted by the luminous animal, which appears more likely. 

 I have thought it my duty to study anew this phenomenon in Lam- 

 pi/ris, because the researches made by Matteucci,t the principal ex- 

 perimenter on this subject, were not conducted after a method 

 altogether irreproachable. In fact, neither this author, nor others, 

 have taken into account the will of the animal, and have not sought 

 to eliminate this cause of incertitude, so that when they placed a glow- 

 worm in carbonic acid (for instance), they were not able to appreciate 

 exactly whether the phosphorescence ceased because the medium did 

 not admit of its being produced, or whether the animal voluntarily 

 refused to shine. In order to decide this, 07ie must first of all try to 

 prevent the animal from lighting-up voluntarily, and force it to become 

 luminous at the will of the experimenter. "With this idea, I took out 

 the cephalic ganglia, which abolished all spontaneous phosphorescence, 

 and replaced the voluntary excitation by the passage of a moderate 



* Translated from the Comptcs-Reiidus of tho French Academy of Sciences, vol. xc, No. 7 

 (February, 1880). 



+ Vide Aimals and Mag. Nat. Hist., vol. xii (1843), i^p. 373, 374. 



