ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 191 



of othf r observers. The bridge is simple and straight ; its ends are 

 rounded and consist of " Punktsubstanz," and into these pass the axons 

 of a few cells which are situated in the immediate neighbourhood. The 

 middle of the bridge is formed of a large number of fibres which pass 

 across the middle line. 



Scales of Leaden Males of Agriades thetis.* — E. A. Cockayne 

 finds that in these aberrant forms the smoky scales and androconia are 

 of the normal shape, size, and colour, but all the colour scales are very 

 thin, and have their distal part rolled up to form a tube. " By reflected 

 light the curled-up edges and tubular ends of these scales look silvery, 

 and under a low-power of the microscope appear as ghostly triangles 

 overlying the dark scales, which are much exposed to direct view and 

 give the leaden colour to the wings." The peculiarities of the scales are 

 probably due to some inborn error of development. Similar aberrations 

 are widespread through the blue Lycaenids. Breeding experiments with 

 the leaden males would be interesting. 



^&' 



Grynandromorph of Papilio lycophron.t — J. J. Joicey and Gr. 

 Talbot describe and figure a remarkable specimen of this Peruvian 

 butterfly in which the right hind wing above is normal. 



Protective Coloration in Lepidoptera.| — J. C. Mottram shows 

 how concealment may be effected by the apparent disruption of surface 

 in a plane at right-angles to the surface. Outline may be concealed by 

 disruptive coloration and solidity by counter-shading. Many small 

 details of pattern are of value in concealment, and one should be slow 

 to conclude on negative evidence that small differences such as often 

 distinguish species can have no value in the struggle for existence. 



Inheritance in Silkworms. § — Onera A. Merritt Hawkes has studied 

 inheritance in the hybrid Philosamia {Attacus) ricini (Boisd.) male and 

 Philosamia cynthia (Drury) female. The plain or non-spotted condition 

 of the larva of P. ricini is recessive to the spotted condition of the larva 

 of P. cynthia (Ning-po variety). The domination in the F^ generation 

 is incomplete ; all the larvae are spotted, but not all have the full 

 complement. The spots are probably represented by a group of related 

 genes in the chromosome, not by one gene. The dominant homozygous 

 and the heterozygous forms can be distinguished only by breeding, as 

 both may be either full-spotted or partly-spotted. A number of 

 abnormal larvse with reduced tubercles occurred in the F2 generation ; 

 when these were mated with normal larvae the character behaved as a 

 recessive. A careful account is given of the minute structure of a 

 tubercle. 



Study of Holly Tortrix Moth.H — L. H. Huie has made a study of 

 Eudemis nsevana, the larva of which eats off the young leaves of holly 



* Trans. Entomol. Soc. London, 1917, pp. 165-8 (1 pi.) 



t Proc. Zool. Soc, 1917, p. 273 (1 pi.). 



X Proc. Zool. Soc, 1917, pp. 253-7 (4 figs.). 



§ Journ. Genetics, vii. (1918) pp. 135-54 (1 pi. and 2 figs.). 



\ Proc. Roy. Phys. Soc. Edinburgh, xx. (1917) pp. 164-78 (1 pi.). 



