No. 1, February, 1921] GENETICS 35 



four species of Geometrids, Tephrosia consonaria and T. extersaria, Boarmia abieiaria and 

 B. consorlaria, a melanic variety has appeared in south England remote from the industrial 

 regions of the North. That melanism is common in industrial and urban districts is explained 

 by the correlation of a greater hardiness with melanism. Natural selection, acting more dras- 

 tically in the manufacturing areas "where the woods and vegetation upon which the larvae 

 feed have been largely destroyed and elsewhere contaminated with a chemical deposit," 

 weeds out individuals of the feebler type form, but permits melanic mutants to develop. 

 Melanics of B. consorlaria as well as of T. consonaria (var. nigra) seem to the author to be 

 "earlier, stronger and larger than the type forms. Moreover, there is often a slight excess 

 of melanics in most crosses."— The author calls attention to a curious inverse relationship 

 between sex and the melanism of consobrinaria which he regards as fortuitous, though it occurs 

 in a single inbred strain and the numbers, in at least one family, are of considerable size. 

 This relationship appears in reciprocal crosses between the heterozygous dominant (melanic) 

 X recessive (type): Heterozygous (melanic) 9 X recessive (type) cf gives approximately: 



9 9 7 heterozygous: 9 recessive 

 (?&9 " :7 



Recessive (type) 9 X heterozygous (melanic) cT gives: — 



9 9 9 heterozygous : 7 recessive 

 cTd" 7 " : 9 



Nearly half of the recorded matings between heterozygote and recessive (6 out of 14) 

 fall into this too symmetrical scheme [that suggests an unorthodox sex-linkage or a sex-linked 

 lethal factor destroying 25 per cent of every brood]. The numbers are small except in the fol- 

 lowing case: recessive (type) 9 X heterozygous melanic cT, giving 64 melanic 9 9 , 49 melanic 

 d^cf ; 49 type 9 9,60 type cf cf .— /. H. Gerould. 



230. Fetch, T. Variation in coconuts. Trop. Agric. Ceylon 54: 1. 1 pi. 1920. 



231. Fhipps, William H. The law of hybridizing. Florists' Exch. 50:814. Oct. 16, 

 1920.— A criticism of Weston, T. A., Rev. of [Diener, R.], The law of hybridizing, etc. 

 [See Bot. Absts. 7, Entries 181, 248.]— G. H. Shull. . 



232. Powell, George T. Thirty years' experience in the application of bud selection 

 in the fruit industry. California Citrograph 5:344, 364r-366. 4 fig- Sept., 1920.— A paper 

 read at a meeting of California nurserymen. Over 30 years ago, the writer publicly advocated 

 propagation from superior orchard trees. Discussion largely relates to the apple. Writer 

 has several thousand apple trees, "practically all" propagated from carefully selected bearing 

 trees; the apparent results are excellent, though comparative tests are not reported. The 

 opinion is expressed that selection for resistance to cold and to disease is important. — Howard 

 B. Frost. 



233. Pridham, J. T. Natural crossing in wheat. Agric. Gaz. New South Wales 31: 457- 

 461. 2 fig. 1920.— Quotations from various authors are given, as to relative abundance of 

 natural crosses. The author cites a few instances of natural crosses coming under his own 

 observation and mentions one commercial variety, Marshall No. 3, an Australian wheat which 

 originated as a natural cross. — L. R. Waldron. 



234. Pridham, J. T. The selection of promising wheat plants. Agric. Gaz. New South 

 Wales 31:548. 1920.— Suggestions to farmers for selecting plants from fields suitable for 

 future increase. — L. R. Waldron. 



235. Rei CHERT, E. T. A biochemic basis for the study of problems of taxonomy, heredity, 

 evolution, etc., with special reference to the starches and tissues of parent-stocks and hybrid 

 stocks and the starches and hemoglobins of varieties, species and genera. Carnegie Inst. Wash- 

 ington Publ. 270. Part l,xi + 376 p. , 34 pL, 820 fig. Part 2, vii + 377-834- 1919.— This memoir. 



