OP THE LUMINOUSNESS OF INSECTS. 493 



but one colour, and it has a yellow-white, thin-skinned fat abdomen. 

 In both, the luminous spots present themselves as four bright points, 

 two of which are upon the antepenultimate abdominal segment, ad 

 two upon the next one. In the smaller L. splcndidula, the male, which 

 is also winged, and is of a brown grey, has a bright glassy spot upon 

 the convex margin of the pronotum : the female, which is entirely of a 

 whitish yellow, and is brown only on the centre of the pronotum, has very 

 short oval elytra, which merely cover the margin of the mesonotum, but 

 it has no wings. In both the luminous parts are two transverse bands 

 on the ventral side of the two penultimate abdominal segments, yet in 

 the female the whole abdomen distributes but a weak light. With 

 respect to size, L. Italica is between both; it is black, with a red prothorax 

 and legs ; two large white spots on the penultimate and antepenultimate 

 abdominal segments display the light. In this species the female does 

 not differ externally from the male; both are winged ; yet some ento- 

 mologists, as Rossi, Illiger, Carus, speak of apterous females, but they 

 have certainly mistaken the larva for the female *. In L. hemiptera, 

 the male has truncated elytra and the female none. It is also the 

 smallest of all, being scarcely four lines in length, entirely of an opaque 

 black, but which is lighter in the female, and the ventral plates of the 

 penultimate and antepenultimate abdominal segments are whitish. But 

 these do not emit the light, which is confined to two round spots on 

 the penultimate segment. In L. splendidula, I have discovered the 

 larvae to be luminous. Muller was acquainted with the larva of 

 L. hemiptera, but he does not say whether it gives light. The 

 L. splcndidula, noctiluca and Italica conceal themselves during the day, 

 and only appear at night-fall, when, upon warm damp evenings, the 

 male Hies about, whereas the female sits tranquilly among the hedges 

 and shrubs, betraying her situation to the male by her much brighter 

 light. L. hemiptera creeps about also by day, but generally in damp 

 weather ; it also appears earlier in the year, namely, towards the end 

 of April, whereas L. splendidula about the end of May and the begin- 

 ning of June, and L. noctiluca, 011 the contrary, is found chiefly towards 

 the end of the summer. 



Their light is of a bluish white, and sometimes also of a greenish 



* Touss. de Charpentier, Horse Entomologies, p. 192. PL VI. f. 5 and 6. He also 

 separates the larger specimens, as L. Lusitanica, and the smaller ones with a black spot 

 upon the pronotum are, according to him, the true L. Italica. 



