THE CANADIAN ENTOMOLOGIST. 179 



moderate ( Phausis J, or very small (Microphotus). The light organs are 

 either brilliant in both sexes {Phausis reticulata), wanting in the male (P. 

 iuacceusa, female unknown), feeble in male and brilliant in female (P/eo- 

 tomus, and probably Microphotus). In the Photini the light organs are 

 completely wanting {Tenaspis, n. g.), obsolete and ineffective (Lucidota, 

 EUychnia most species) ; well developed in both sexes, but more brilliant 

 in male than female {Pyraciomena, Photinus) ; equally brilliant in both 

 sexes {P/ioturis) : in all these the antennae are long, either slender or 

 broad, and closely approximate ; the eyes are widely separated on the 

 upper side, and usually also beneath. In Matheteus and Polyclasis the 

 antennae are pectinate, or bipectinate, and rather widely separated ; the 

 eyes are more distant, and the light organs wanting. 



The Phengodini are known only by the male. The eyes are lateral, 

 convex, moderate in size, and widely separated ; the antennae are distant 

 at their insertion, plumose in Phengodes and Zarhipis (n. g.) ; bipectinate 

 in Mastinocerus and Cenophengus (n. g.) ; pectinate in Pterolus, and serrate 

 in Tytthonyx, if I am correct in associating that genus with this tribe. 

 Phengodes is said by Lacordaire* to be luminous, while the observations 

 of Mrs. King above cited prove that Mastinocerus is also phosphorescent. 



From this detailed statement it may be inferred that there is no dis- 

 tinct correlation between the eyes, the antennae, and the light organs of 

 the two sexes which obtains for the whole sub-family. 



That the eyes of the male should in comparison with the other organs 

 of special sense, the antennae, be more largely developed than in the 

 female, is explicable from the more generally active disposition of that 

 sex, but that these characters should prevail in the contradictory cate- 

 gories, where the female is more brilliant, and where she is less brilliant 

 than the male, does not seem to me explicable either on grounds of tele- 

 ology or natural selection, and especially do these explanations seem 

 imperfect when we consider that the largest eyes are possessed by those 

 males which seek the most brilliant, but also the most helpless females. 



The luminous powers of these insects suggest three distinct investi- 

 gations, which seem to me very important, and to which I would earnestly 

 invite the attenti n of my colleagues in other branches of science : 



ist. Spectroscopic examination of the nature of the light, and an 



Gen. Col., iv., 345. 



