ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 25 



the larvae feed inside the bulb and may migrate from one to another. 

 The second pest is a small black insect which is supposed to lay its eggs 

 near the base of the leaves. The larvaj burrow into the bulb and de- 

 stroy the whole interior. But the life-history has not been completely 

 traced. 



Bristles of G-reenbottle Fly.* — Phineas W. Whiting has made a 

 study of variation and heredity in regard to the number of bristles in 

 Lucilia sericata Meig. He deals with a dozen dorsal bristles — posterior 

 dorsocentrals and acrostichals. He reaches two general conclusions : 

 (1) that reduction in bristles teuds -to affect the males more than the 

 females, while additional bristles are found more often in the females ; 

 and (2) that distribution as well as number of bristles is hereditary. Of 

 the 5367 flies bred, 2708 are males and 2659 are females, giving practical 

 equality. Reduction in the males is 74<s*5 bristles, while inithe females 

 it is only 455 ' 5 bristles. Reduction rarely goes beyond the loss of two 

 bristles in a single fly. There are 210 bristles added in the males, while 

 there are 343 added in the females. Thus addition affects the females 

 more than the males. No distinction is made between bristles of large 

 and bristles of small size. 



Larva and Pupa of Frit-fly.f — T. R. Hewitt fills a gap in giving 

 a description of these stages in Oscinis frit, one of the worst cereal pests 

 in Europe. The maggot is about 3 mm. in length and 0'3 mm. in 

 thickness. It has eleven segments. The head bears two one-jointed 

 papilla? or feelers, two slight thickenings with spines probably sensory, 

 and hook-like spines dorsally. The mouth shows mouth-hooks or 

 " mandibles," and there is a cephalo-pharyngeal skeleton with several 

 paired sclerites in the mouth and gullet. At the posterior margin of the 

 foremost body segment are situated the anterior spiracles with a fine 

 sieve-like opening. The large tail-segment bears posteriorly the hind 

 pah' of spiracles on prominent backward-projecting spiracles. The 

 spiracular opening is bounded by a thick chitinous ring. The adjacent 

 cuticle has four very peculiar sets of radiating thickened ridges, situated 

 between openings of the spiracular branches, and they probably serve as 

 a protection to the spiracles, admitting air and excluding foreign material 

 when the spiracles are retracted. The anus is at the end of the minute 

 anal segment, which projects ventrally from the spiracular segment. 

 There is a semicircular anal pro-leg at each side of the median slit. The 

 puparium is red- brown, about 2 '5 mm. in length and 1 mm. in breadth. 

 The posterior spiracles are prominent, and the larval mouth-hooks can 

 be seen. The outline of the developing fly, with the contour of the 

 body, and the beginnings of the wings and legs, can be seen in the 

 cleared specimen. 



Gametogenesis in Hybrid Moths.} — J. W. H. Harrison and L. 

 Doncaster have studied hybrid Bistoninre and their gametogenesis. 



* Arner. Nat., xlviii. (1914) pp. 339-55. 



t Sci. Proc. R. Dublin Soc, xiv. (3914) pp. 313-16 (1 pi.). 



% Journ. Genetics, iii. (1914) pp. 229-48 (2 pis.). 



