66 E,ev. H. S. Gorluam on the 



emitted considerable, sometimes greater in the ? . Eyes 

 large, sometimes excessive. Antennae simple, usually 

 filiform. Genera, — Gratomorphus, — C. giganteus, 0. 

 fuscipennis. Lucermda, — L. fenestrata, Aspidosoma, — 

 A. laterale (^ . A. cegrotum, Gorh. c? ?• Luclola, — L. 

 italica ; L. lusitanica ; L. vespertina. Photuris, — P. 

 pennsylvanica. 



iii. Species in ^Yllicll the female is apterous or with 

 rudimentary wings ; light emitted often very great in the 

 female, and often only rudimentary traces of it in the 

 male. Antennas usually rudimentary. Eyes large in the 

 male, often excessively so, occupying nearly the whole 

 head. Genera, — Pleotomus, — P. palle^is, S ?; Laiwpro- 

 pliorus nepcdensis S ', Microphotus, M. n. sp. Lampyrls, — 

 L.noctilucaS ?; L. 7nmiritanica^ ?; L. sp. ? Africa; 

 Lamprorhiza, — L. Delarouzei S ? • 



iv. Three abnormal genera which do not seem to form 

 cases in point. AlycJmus, — A. xantliorrhaphus S ? • This 

 being quite non-luminous appears only to offer negative 

 evidence. The eyes arc not developed. Dioptoma, — 

 D. Adcmisi, — the eyes arc enormous, but I do not know 

 anything about the luminosity. Amythetes, — A. fastigiaia. 

 The antennae are plumose, and both sexes I believe 

 luminous, but the insect is quite abnormal ; the antenme 

 are redundant in the number of joints and the plumosity 

 very soft and fine. I should consider them simple rather 

 than specialised. 



With regard to the power of withdrawing the light proved 

 I believe to exist in these insects, whether suddenly and in- 

 termittently as in the instance of the Luciola, or gradually 

 as I have observed in L. noctiluca, the explanation is I think 

 that the external white vitreous-looking parts are only dia- 

 phanous, not themselves the source of the light which is 

 within the body of the insect and can be pressed against 

 these windows, or retired from them at its pleasure. 



I think Newport observed that these segments in the 

 female of L, noctUuca were detached from the internal 

 parts on dissecting them. The circumstance of the 

 Luciolas thus flashing in unison would on this hypothesis 

 easily be accounted for, by any exciting cause, such as the 

 arrival in the swarm of a fresh female, or the gusts of air, 

 Avhich affected them all at one time. And the comparative 

 hardness of the body in this genus seems to favour the 

 idea that this may be really the case. 



