ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 713 



recessiveness, and numerical proportions, and may even break down and 

 blend, or one colour be otherwise influenced or modified by the presence, 

 in a mating, of another. Larval pattern and cocoon colour characters 

 do not, except as coincidences, follow the same parent in dominance. 

 In cross-mating, combining opposed larval and cocoon characters, domi- 

 nance in larval pattern may be with the paternal type, in the cocoon 

 colour with the maternal, or vice versa, or both dominances may rest 

 with the paternal or the maternal type. Dominance is a function of the 

 characteristic, not of the parental influence. Dominance is not a 

 function of sex or of bodily vigour. 



While in larval colour-pattern characters the inheritance behaviour 

 is rigorously alternative and Mendelian, dominance always being con- 

 sistent in relation to a given colour-pattern as related to another, this is 

 not true of cocoon colours. With these, characteristic differences pecu- 

 liar to strain (or race) and individual are marked. Strain and individual 

 idiosyncrasies are real and important, and thus, sweeping generalisations 

 concerning the inheritance behaviour of the cocoon colours, tending to 

 class them unreservedly in the Mendelian category, cannot be made. 

 The tendency is for them to behave in Mendelian manner, but it is a 

 tendency subject to numerous, marked, and various inconsistencies and 

 irregularities. In double matings, i.e. matings of one female with more 

 than one male, these males representing different types of larval and 

 cocoon characters, interesting modifications and interactions of influence 

 are to be noted. The reality of strain potency over character potency 

 is made manifest in these double matings. Quantity and quality of 

 silk, subsidiary larval marking, wing-pattern and wing-venation varia- 

 tions, and degree of adhesiveness of eggs, are all fluctuating, non-alter- 

 native characters. Double cocooning is a phenomenon determined by 

 ontogenetic circumstances. Crowding is not the causal circumstance. 

 Of various sport appearances of larval " cocoon " and imaginal characters 

 only one, namely, larval melanism or " monicaudness, 1, is of prepotent or 

 dominant nature when crossed with the normal condition. All other 

 sport characteristics, including various larval colour and structural 

 abnormalities, active flight of moths, absence or rudimentary condition 

 of wings, unusual colour-patterns, including melanism of moths, are 

 extinguished by cross-mating. Fertility is not affected by the age of 

 the egg-cells, but seems to be unfavourably affected by the age of the 

 spermatozoa. Old spermatozoa seem less potent than younger ones. 



A scientific study of inheritance in silkworms may be of service to 

 commercial silk-culture. 



Treatise on Insects.*— A. Berlese continues his great treatise on 

 insects, the last published fasciculi dealing with the fatty bodies, the 

 respiratory system, and the reproductive organs. 



Galleria melonella.f — S. Metalnikov gives an account of a series 

 -of experimental observations on the nutrition and excretion of this 

 caterpillars of this moth, which feed entirely on bees' wax. The femaL 

 lays her eggs on pieces of wax or wood within the hive. The littl 



* Gli Insetti. Milan : 1908, i. fasc. 28-30, pp. 801-96 (figs. 1002-1197) 

 t Arch. Zool. Exper., viii. (1908) pp. 289-383 (5 pis.). 



Bee. 16th, 10 08 3 a 



