INVERTEBRATA, CRTPTOGAMIA, MICROSCOPY, ETC. 777 



stomach, and intestine are similarly compressed against the posterior 

 wall. The compression of these organs is so great as seemingly to 

 preclude their functional action, the stomach appearing to be quite 

 incapacitated for its normal office of digestion. Yet the continued 

 vitality of the ant is sufficient evidence that alimentation must still 

 exist ; and as it is not at all probable that the crop could assume the 

 function of a digesting organ without injury to its stores, it seems as 

 if some of the liquid food must make its way into the stomach and 

 intestine, despite their extreme compression, and be there prepared 

 for aliment. 



It is, in fact, a puzzling question. Dr. McCook is inclined to 

 think stomach digestion in some instances impossible. But the con- 

 tinued vitality of the ant seems to render it necessary, despite its 

 apparent impossibility. 



Structure of the Lampyridae with reference to their Phos- 

 phorescence.* — The Eev. H. S. Gorham arrives at the conclusion 

 that the sexual instinct has played a large part in moulding the 

 external structure of this group of beetles, and that it is to that we 

 may look for an adequate explanation of the development of phos- 

 phorescent light, though, perhaps, not for its origin. 



In the first place, it is to be observed that all the species of this 

 family do not j)ossess the luminous faculty in equal degree ; but that 

 on the contrary, while some are highly luminous in both sexes, some 

 are only highly so in the female, some are not luminous in either 

 sex, and some (though this appears rather doubtful) are luminous in 

 the males, and not so, or much less so, in the female. 



The part which this faculty of emitting light plays in the economy 

 of nature has been long and earnestly debated. The most general 

 view, and one which the author's observations tend to confirm, is that 

 it serves as a beacon to attract the male to the female ; but he believes 

 this to be the case only in a special sense in those species which do 

 not assemble, and especially in those in which the females are in- 

 capable of flight. In other cases he believes that both sexes are 

 attracted, and enabled by this means to assemble at niglit for their 

 union. These inferences are drawn from the consideration of the 

 relative development of the eyes, together with what is known of the 

 habits of the various species. 



The eyes of the Lampyridae are, he finds, developed in magnitude 

 according to the amount of luminosity of the species considered ; and 

 the other parts which he has taken account of, together with these, 

 are the antennte, of which there is a very great diversity, both between 

 the sexes and in the genera ; the elytra, which are also subject to 

 sexual and generic limitations, and finally the size of the abdomen in 

 the female. 



The last-mentioned is no doubt, as in other apterous females, the 

 result of an increased production of ova. These are in the Lam- 

 l»yridto laid on roots and other substances near the grouml, where the 



♦ 'Trans. Entomol. Soc. Lond.,' 1880, [>\t. G3-<;. 



