INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 779 



ii. Species in which both sexes are winged ; light emitted con- 

 siderable, sometimes greater in the P ; eyes large, sometimes ex- 

 cessive ; antennae simple, usually filiform : — Cratomorphus, Lucernula, 

 Aspidosoma, Luciola, and Plioturis. 



iii. Species in which 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 ; antennae usually rudimentary ; 

 eyes large in the male, often excessively so, occupying nearly the 

 whole head : — Pleotomus, Lamprophorus, MicropTiotus, Lampyris, and 

 LmnprorMza. 



In the discussion * which followed the paper, the author, in reply 

 to a question how he had deterinincd the intensity of the light without 

 actual photometric measurement of the live insects, stated that tlie 

 light-emitting segments at the extremity of the abdomen were dis- 

 tinguisliable by their white, vitreous appearance, and that he con- 

 sidered their number and size to indicate the phosphorescent power. 

 He did not consider that these vitreous segments were themselves 

 luminous, but that the source of light was within the body of the 

 insect, and shone through the transparent segments, or could be 

 withdrawn at pleasure. In this manner he thought the gradual 

 extinction or intermittent flashing of the light might be explained. 



Influence of Temperature in producing Varieties of Lepi- 

 doptera.t — G. Dorfmcister has observed a specimen of Vanessa 

 Atalanta, stated to have been bred from a pupa of the year before, 

 with the lower side of the hind wings buff-coloured ; he therefore 

 made experiments to test the caiise of this by trying to breed similar 

 forms, and succeeded in producing just such a specimen as the first. 

 As the species docs not naturally pass the winter in the pupa state in 

 this part of the world, many puptc were killed by cold, and the tem- 

 perature at which they thrive was discovered in the course of the 

 experiments. The variety mentioned was obtained among tlie 

 images from pupa? which had become pupre at 10^ to 11^ Ii., and 

 were afterwards kept at 7^"" to 5.V" R., and some varieties resembling 

 it resulted from the same treatment ; pupae, however, kept at from 1° 

 to 2° R. either died or furnished crippled images. 



Using higlicr temjieratures, and forcing the pupae in a shorter 

 time, he found tliat several similar varieties were i)roduccd, the 

 method being to allow the pupation of the caterpillars to take i)laco 

 between 7h^ and ll'^ R., to keep the pupae from three to seven days 

 at the same temperature, and for the remaining eighteen to thirty 

 days to keep tliem in a room of sometimes tolerably low temperature. 



With Vitnessa urticce he found that diminishing the warmtli pro- 

 duced stages of transition to the Lai)hxnd form, Vanessa levaiia, how- 

 ever, which is accustomed to pass the winter as pupa, developed no 

 varieties when exposed to a greatly diininishod toiiiperaturc. 



In order to determine the exact period at which the future 

 colourings and markings are fixed on the insect, he recalls the fact 



* Iliiil. (Proc), p. vi. 



t 'MT. Nivtvirw. Vit. Stciuriimrk ' (IXSO), Al.liaii.ll., \k 3. I pliilo. 



