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THE AMERICAN NATURALIST [Vol. XLVHI 



This same work of Tower is one of them. The effects just noted 

 were merely ontogenetic. However, he made other experiments 

 in which the effect seemed to be passed on by heredity. The fac- 

 tors in the various experiments with L. decemlineata were 35°, 

 45 per cent, and low atmosphere pressure (p. 287) ; "hot, dry" 

 (p. 288) ; "hot, dry and low pressure" (p. 288) ; and "hot, 

 moist" (p. 291), probably 31.2°, 94 per cent. Those with L. 

 mulitceniata were 30° and saturation (p. 292 and p. 293) ; and 

 the one with L. undecemlineata was " 10 C. above the average and 

 a relative humidity of 40 per cent." The work is of such im- 

 portance because of its pioneer character that it would be un- 

 gracious to complain too strongly, but the fact is that it is 

 impossible to tell from the data given whether the effects are 

 caused by humidity or by temperature or by a combination of 

 the two. Bateson's idea that there are no effects to be explained 

 need not concern us here. 



There is a long series of interesting papers starting in 1895 

 by Fischer. As has already been mentioned, he finds that certain 

 high temperature grades produce effects which are similar to 

 those produced by certain low temperature grades. The con- 

 ditions of humidity are rarely mentioned, not to say considered. 

 However, he occasionally confesses that they are important, as 

 when he tells us 4 that it is necessary to have the warm air dry and 

 the cold air moist in order to get similar forms of Vanessa by the 

 application of moderate cold and moderate heat. I suspect hu- 

 midity largely enters into the other experiments also for in one 

 with high temperature, 5 which gave the same results as certain 

 low temperatures and presumably high humidity he says the hu- 

 midity was high. 



Like Tower's experiments with beetles these concern color 

 alone. Pictet 6 and Federley, 7 especially, have considered the 

 effect of environmental factors upon the form of lepidopterous 

 scales. Federley calls his work " Tempera tur-experimente " and 

 Pictet "Influence de PHumidite" but neither enables us to dif- 

 ferentiate the effects of the two factors, although both obtained 

 striking results. Kominsky 8 modified to a considerable extent 



* Algemeine Zeitschrift fur Entomologie, VIII, p. 274, 1903. 



s Illustrierte Zeitschrift fur Entomologie, IV, p. 134, 1899. 



aMemoires de la Societe de Physique et d'Histoire Naturelle de Gen&ve, 

 XXXV, Fasc. 2, 1905. 



t Festschrift fur Palmen, No. 16, Helsingfors, 1905. 



sZool. Jahrbiicher. Alt. fur Allg. Zool. und Physiologie, pp. 321-338, 

 1911. 



