THE CANADIAN ENTOMOLOGIST. 361 



light must be less intense than that of the male, but I have not observed 

 them at night. In the cyanide killing-bottle the organ of the female 

 augiilata shines as four luminous points. The light-emission of the male 

 scintillans is very similar to that of the pyralis, but shorter in duration, 

 and not delivered during a dipping flight, but when flitting irregularly 

 around bushes, etc. In appearance and location of the light-organ the 

 male sci?itt/ians is a diminutive male pyralis, and from Watase's drawings 

 the female scintillans much resembles the itxi\d\t pyralis. 



Dr. Frederick Knab (Can. Ent., 1905, Vol. 37, pp. 238-239) has men- 

 tioned the difference in quality between the light oi Photinus scintillans and 

 Fhoturis pennsylvanica, and Turner (Psyche, i882,Vol. 3, p. 309), has called 

 attention to the similarities and differences between the light of Fkotifius 

 pyralis, Photuris pe?msylvanica and Pyrophorus noctilucus. Aside from the 

 fact that the pennsylvanica is a considerably larger insect, and, therefore, 

 witha larger luminous apparatus, there is certainly a distinct difference in the 

 light. I have never submitted the light of scintillans to analysis with a spec- 

 troscope, but I have compared the light of pyralis, pennsylvanica and 

 consanguineus with a small Schmidt & Hasnsch spectroscope, having an 

 arbitrary numerical scale reading fron o in the red (the lower end of the 

 visible spectrum) to 65, the end of the visible violet, and on which the 

 sodium D-line corresponds to No. 13, and the calcium lines Hj and H2 to 

 56.5 and 58.5 respectively. This little instrument resolved the light of 

 ihe pyralis into a continuous band, extending from 5 to 25 of the scale, 

 corresponding to the "structureless, unsymmetrical band" obtained by 

 Ives and Coblentz (Bull, of the Bur. Standards, Wash., D. C, 1910, Vol. 

 6, pp. 321-336), in their excellent work on the luminous efficiency of the 

 fire-fly. The light emitted by the pefinsylvanica showed a shorter spec- 

 trum, extending from 7 to 24 of the scale, and that of the consanguineus 

 even shorter, extending from 7 to 22 of the scale. These were single 

 observations, which I have unfortunately been unable to more than 

 partially confirm, but the fact that the spectrum of the light emitted by 

 the two latter species appears to be shorter in the red end than that of the 

 pyralis, would seem to account for its more decided green tinge. The red 

 light which Dr. Knab and Mr. Barber (Proc. Ent. Soc. Wash, 1908, Vol. 9, 

 pp. 41-43) mention as being noted in tropical species of P/iengodes, is not 

 regarded by Dr. Coblentz as being due to a.bsorption in the chitin, as it 

 would be but poor economy to generate such an efficient light, and then 

 absorb a portion of it before its passage from the generating organ. 



