128 GENETICS [Bot. Absts., Vol. IV. 



mines rate of growth, form, symmetry, etc., both parents determine details. In general, 

 Mendelian principles govern. — Interspecific crosses give varying results. L. signaticollis X 

 L. diversa give Fi truly intermediate in all respects, and F 2 consisting of 1 diversa : 2 mid- 

 type : 1 signalicollis. Total type remains as unit, no interchange occurs. These are results 

 when rate of ontogenetic development (Ac) is same in both species. When Ac is made different 

 for two species, by climatic changes, result of cross suggests that one parent is heterozygous, 

 other homozygous; but apparent signalicollis type in Fi is shown to be masked heterozygote, 

 a fixed hybrid, breeding true. Group of determiners is bound together in firm association. 

 These fixed hybrids, if discovered in nature, would have been regarded as new species 

 (mutant). — L. undecimlineata X L. signalicollis exhibit three groups of characters (ely- 

 tral pattern, larval pattern, lipoid color) which dissociate as groups. Fi is uniform, and 

 reciprocals are alike in adult, but maternal in larva. When Ac values are same, F 2 gives typ- 

 ical tri-hybrid results. With Ac conditions different, results are various. Under one set of 

 conditions Fi consisted of 1 undecimlineala : 2 mid-type : 1 signalicollis, each with different 

 behavior in F 2 . Changing temperature further complicated results. — L. decemlineata 9 X 

 L. diversa d" gave Fi and F 2 pure decemlineata in appearance but diversa in rate of growth and 

 food preference. — L. decemlineata X L. oblongata gave Fi in variety of combinations of pa- 

 rental characters, falling into three general classes, decemlineata, intermediate, and oblongata, 

 each with different behavior in F 2 . — L. decemlineata X L. multilaeniata gave Fi with decern- 

 lineata dominant (modifiable by external conditions) and F 2 on the whole of three types, dec- 

 emlineata, heterozygotes, and multitaeniata. — Analysis of heterogeneity of certain pattern 

 characters indicates that biotypes may be isolated. One biotype was observed to arise from 

 another, perhaps due to change in environment. Attempts to accumulate quantitative 

 differences have failed, but syntheses of characters have been readily possible. General popu- 

 lation in several regions was analyzed and found to be different in each, but difference is not 

 attributed to environment. — A. Franklin Shull. 



795. Trateur, J. L. La nature de la telegonie. [The nature of telegony.] Reunion soc. 

 beige biol. 1919: 883-884. 1919. 



796. Tufts, W. P. Almond pollination. California Sta. Bull. 306: 337-366. 15 fig. 1919. 

 — Self-sterility and inter-fertility of commercial varieties affect choice of varieties and sys- 

 tems of planting. Even in interfertile varieties it is important to know commerical value of 

 pollenizer, time of bloom, and amount and germinability of pollen of varieties used as pollen- 

 izers. Blooming periods and production of pollen in almond varieties are reported. Almond 

 varieties are roughly divided into two classes: early and late bloomers. First blossoms in 

 certain varieties each season may yield a smaller amount of pollen of inferior viability to that 

 produced by flowers on same tree several days later. There is considerable variation in 

 amount of pollen produced in different varieties. Satisfactory artificial germination was 

 secured in 12 per cent cane sugar solution. All seventeen varieties thus far tested have proved 

 self-sterile at least in certain years. Certain varieties are intersterile. A list of satisfactory 

 pollenizers for important commerical varieties is given. Pollenizing agencies such as honey 

 bees are necessary for a good crop. One colony of honey bees should be provided for each 

 acre of orchard. — E. B. Babcock. 



797. Tufts, W. P. Pollination of the Bartlett pear. California Sta. Bull. 307: 369-390. 

 8 fig. 1919. — Experiments to determine whether Bartlett pears are benefited by cross-pollina- 

 tion. Production and viability of pollen of varieties used was determined in 12 per cent cane- 

 sugar solution. Blooming period in Bartlett is longer than in other varieties tested. Bart- 

 lett is only partially self sterile in valleys and practically so in foothills. Author recommends 

 interplanting of other varieties for cross-pollination. No cases of inter-sterility were found. 

 Any variety with same flowering period may be used. Cross-pollinated Bartletts are less 

 inclined to June drop than self-pollinated. \- pollinating agents one colony of honey bees 

 should be provided per acre of orchard. — ./. L. Collins. 



