ON THE SCALES OF EUROPEAN ZYfiyENIDES. 273 



nearer to the original Zygaenid type than either of those previously 

 described, its scaling is not much unlike that of Iiio, but Inn itself 

 has in some instances advanced beyond it. The scales are long 

 ovals, more or less sparsely planted, and rarely bilid, though there is 

 a tendenoj that way in several species. It will be observed that 

 whenever tlioso scales suggest a triangular shape, the base of the 

 triangle is towards the base of the scale, whereas in the higher 

 Zjiiiaenae the reverse is the case (and generally, indeed, their scales 

 are oblong rather than triangular). This is an additional reason for 

 referring mdiloti to this group (c. f. figs. 7 and 12). There is a certain 

 amount of dilierence (perhaps due to long isolation in dilierent 

 localities) between Mr. Tutt's continental Z. minos (figs. 9, 10) and my 

 own Irish specimens (figs. 7, 8). 



The method employed has been simply to mount portions of the 

 wings of dry specimens in Canada balsam, using a rather thin (but not 

 too thin) solution. The balsam will permeate well enough on pressing 

 the cover-glass, or it may be assisted by ijentle heating over a spirit 

 lamp. A few bubbles, however, are not deleterious, so long as they 

 do not obscure anything that one wants to see. Specimens possessing 

 at least one upper and one lower wing will do, though it is advisable 

 that they be not much worn. The chief thing to guard against, 

 however, is folded and curled scales — these occur in specimens which 

 have not emerged satisfactorily. I shall be glad of assistance in local 

 British forms, some of which may prove of interest ; also of any 

 Continental specimens with reliable data. Mr. Tutt will take charge 

 of any odds and ends for me. 



Description of plate. — Fig. 1 — Scales of Zy^/aena hmiverae, 

 lower wing. Fig. 2 — Scales of Z. lonicerae, upper wing. Fig. 3 — 

 Scales of Z. trifolii, lower wing. Fig. 4 — Scales of Z. trifolii, 

 upper wing. Fig. 5 — Scales of Z. filipendulae , lower wing. Fig. 6 — 

 Scales of Z. filipendulae, upper wing. Fig. 7 — Scales of Z. vdnos 

 (Irish), lower wing. Fig. 8 — Scales of Z. vdnos (Irish), upper wing. 

 Fig 9 — Scales of Z. nmios (Continental), lower Aving. Fig. 10 — 

 Scales of Z. minos (Continental), upper wing. Fig. 11 — Scales of 

 Z. nieliloti, lower wing. Fig. 12 — -Scales of Z. meliloti, upper wing. 



yote on the illustrations.- — These have been sketched with an Abbe 

 drawing camera. The striae are not works of the imagination,, but 

 the cross striations have been left out, except in one scale, in fig. 12, 

 because it was found impossible to get them in satisfactorily by this 

 method. These " cross striations " occur principally on the scales 

 which have a metallic aspect. All the figures are of the same 

 magnification, viz., x 480 diam. [They have been reduced ^ in 

 making the plate. — Ed.] 



The fluctuation in numbers of Sedentary Species of Lepidoptera, 



with some Criticisms suggested by the List recently issued by 



the Protection Committee. 



By JOHN BULL. 



Apart from the periodic abundance in this country of certain 

 species of Lepidoptera of undoubted migrating tendency, such as Colias 

 liyale, C. edusa, Pijrameis cardiu, Sphinx convolvuli, Deilepliila (jalii, 



