ZOOLOGY AND BOTANY. MICKDSCOPY, ETC. 387 



The larvte crawl about, or are distributed passively. The larvae aud 

 pupge usually pass their whole existence under water ; the adults are 

 aerial and nocturnal. The eggs of JV. iccuisalis are laid on the margins 

 of the leaves of Potamogeton natans ; there are no tracheal gills ; 

 cases are made as in the other species. 



Intersex of Amorpha populi.* — E. A. Cockayne describes a specimen 

 of Amorpha populi in which, although head, thorax, and wings appeared 

 to be male, the abdomen was full and rounded like that of a female. 

 Dissection showed that both external and internal reproductive organs 

 were male, but with many abnormalties, which are described in: detail. 

 The interest of the specimen lies in the fact that it resembles closely the 

 Lymantrias derived from crossing to which Goldschmidt gave the name 

 " intersex," to distinguish them from ordinary halved gynandromorphs, 

 wdiich must arise from a different cause. The form examined also arose 

 from crossing various races of British A. popidi for several generations. 



Cocoon Colour in Lepidoptera.f — 0. A. Merritt Hawkes has studied 

 the cocoon of Plusia moneta and other Lepidoptera with a view to 

 elucidating the factors determining changes in cocoon-colour. The 

 subject is almost untouched ground, but certain factors in the production 

 of white cocoons are suggested provisionally. These are :— 1. The 

 absence of an intestinal fluid (i.e. either an excretion from the intestine 

 or the secretion of the Malpighiau tubules). 2. A comparatively dry 

 environment. 3. A lack of foreign particles. 4. A leduction of an 

 original yellow colour. Examples are given in illustration of each of 

 these factors, and the author believes that further investigation will 

 probably co-ordinate the effect upon white silk of intestinal fluids and 

 atmospheric moisture. 



Rein-sheath in Pleheiid Blue Butterflies.l — T. A. Chapman adds a 

 note to a previous paper on the pairing of Plebeiid Blue Butterflies, to 

 correct a statement in regard to the rein-sheath. He finds that this 

 remarkable structure is made of scales, but scales of a very unusual 

 nature. The end, by which each was presumably attached to the rein, 

 tapers to a very small point, less like tlie usual socket of a scale than 

 like the traces of abortive hairs or scales. The body of the scales is 

 curled or twisted, and the curlings or twistings are so intertwined as to 

 hold the scales together to form a cylinder. The female butterfly 

 possesses this cylinder on emerging from the pupa, but loses it as soon 

 as pairing is over. The special character of the f urea in the floor of the 

 male genital cavity is probably related to the rein and its sheath. The 

 investigator has verified the presence of the sheath in seven species, 

 and believes that it will be found to occur, with differences of detail in 

 structure, in all the Blue Plebeiids. 



* Traus. Eutomol. Soc. Loudon, iii.-iv. (1916, publ. 1917) pp. 343-4 (1 pi.). 



t Trans. Entomol. Soc. Loudon, iii.-iv. (1916, publ. 1917) pp. 404-11. 



t Trans. Entomol. Soc. Loudon, iii.-iv. (1916, publ. 1917) pp. 297-300 (2 pis.). 



