JOSEPH KRAFKA, JR. 463 



That the number of facets is not dependent upon the length of 

 the immature stage is shown by experiments in which only a part 

 of development was passed at one temperature and the remainder 

 at another. 



Temperature affects the reaction determining the number of 

 facets in approximately the same way that it affects the other devel- 

 opmental reactions, hence the apparent correlation between facet 

 number and the length of the immature stage. 



Variability as expressed by the coefficient of variability has a ten- 

 dency to increase with temperature. Standard deviation, on the 

 other hand, appears to decrease with rise in temperature. 



Neither inheritance nor induction effects are exhibited by this 

 material. 



This study shows that environment may markedly affect the so- 

 matic expression of one Mendelian factor (bar eye), while it has no 

 visible influence on another (white eye). 



BIBLIOGRAPHY. 



Arrhenius, S., Quantitative laws in biological chemistry, London, 1915. 

 Bachmetjew, P., Experimentelle entomologische Studien von physikalisch- 



chemischen Standpunkt aus, Leipsic, 1901. 

 Balls, W. A., Ann. BoL, 1905, xxii, 557. 



Baur, E., Einfiihrung in die experimentelle Vererbungslehre, Berlin, 1911. 

 Bayliss, W. M., The nature of enzyme action, London, 1914, 3rd edition. 

 Blackman, F. F., Ann. BoL, 1905, xix, 281. 

 Davenport, C. B., Experimental morphology. New York, 1899. 

 Ernst, C, Z. physik. Chem., 1901, xxxvii, 448. 

 Hertwig, O., Arch. mikr. Anat., 1898, li, 319. 

 Hoge, M. A., /. Exp. Zool., 1915, xviii, 241. 

 Howell, W. H., Text-book of physiology, Philadelphia, 1905. 

 Laughlin, H. H., Carnegie Inst, of Washington, Pub. No. 265, 1919, 1-48. 

 Lauritzen, J. I., Phytopath., 1919, ix, 7. 

 Lillie, R. S., Biol. Bull, 1917, xxxii, 131. 

 Loeb, J., Arch. ges. Physiol., 1908, cxxiv, 411. 

 Loeb, J., and Northrop, J. H., /. Biol. Chem., 1917, xxxii, 103. 

 Maxwell, S. S., /. Biol. Chem., 1907, iii, 359. 

 Merrifield, F., Tr. Entomol. Sac, 1891, 151. 

 Metz, C. W., Genetics, 1916-17, i, 591. 

 Middleton, A. R., Genetics, 1918, iii, 534. 

 Morgan, T. H., Am. Nat., 1915, xlix. 385. 



