294 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



gives birth occasionally to a winged generation of both sex- 

 es, the females of which lay only two or three eggs each. 



The apterous Phylloxera is also dimorphous, a smooth-bod- 

 ied form living in little galls growing on the leaves of the 

 vine, where it is comparatively harmless, and a tuberculate 

 form living in the modules it produces on the root fibres, 

 causing first the smaller and then the main roots to rot, weak- 

 ening in the first instance, and finally killing the whole vine. 

 Each form has its winged generation. 12 A^June 13, 1873, 

 133. ' 



CONTEOLLIXG SEX IN BUTTERFLIES. 



A suggestive article as to the possibility of controlling 

 sexes in butterflies has been communicated to the American 

 Naturalist by Mrs. Mary Treat, and from the results of nu- 

 merous experiments she finds occasion to believe that the 

 larvae to which the freshest and most tempting food was sup- 

 plied in unlimited quantity nearly always developed into fe- 

 male butterflies, while those for which the supply of food 

 was limited almost as uniformly proved to be males. Dr. 

 Packard is, however, inclined to think that the sex of this in- 

 sect, as well as that of all animals from eggs, is determined 

 at or about the time of conception, or, at least, early in the 

 embryonic condition. In the honey-bee, especially, it has been 

 proved that the sex is decided at the time the ^o^^ leaves the 

 ova-duct. The sex in man, according to Koelliker, becomes 

 fixed toward the end of the second month of foetal life. 5 2>, 

 March, 1 873, 1 27 and 175. 



DISCOVERIES BY THE " CHALLENGER" EXPEDITION. 



One of the first fruits of the Challenger expedition is pre- 

 sented by Dr. Suhms, naturalist of the expedition, in the form 

 of a description of a new genus of amphipod crustacean. 

 This was obtained ofi* Cape Vincent, on raising the trawl 

 from a depth of 1090 fathoms; but it is not certain whether 

 it belonged to the bottom, or was accidentally swept into the 

 trawl at some point nearer the surface. The genus has been 

 named Thaumops pellucida, and is characterized by its trans- 

 parent body and numerous faceted eyes. Another crusta- 

 cean obtained is entirely without eyes. 12 A, 3farch 13, 

 1873,372. 



