COSYMBIA. By L. B. Prout. 143 



the general range of variation, but it is by no means so certain ttiat Lambillion has done equally good 

 service in imposing separate names upon them, especially as they were not very fully characterized. It is, 

 however, necessary to quote them, if only to prevent future writers from multiplying synonyms through 

 ignorance of them. — ab. linearia Lambill. Median band strongly developed. This band is described as Imearia. 

 "brown", which evidently refers to the blending of the dark-grey and red scales. I take the aberration 

 figured by Barrett, pi. 328, fig. 2 c as a good illustration of this form. — ab. unicoloria Lambill. ''Macular band unicoloria. 

 of distal margin obliterated". Probably Lambillion regarded as typical a rather common form with moderately 

 strong subterminal shading (about as that of our figure of porata, 4o), and would regard our pendularia 

 figure as intermediate between that type and true unicoloria; in that case the latter will only differ from ab. 

 depulsa in having normally developed ocelli. — ab. brunnearia Lambill. "Wings strongly charged with brown brunnearia. 

 atoms". Here again Lambillion is scarcely sufficiently explicit. In ab. griseolata the atoms could not be 

 called brown, so 1 suppose the reference, as in ab. linearia, is to the blending of grey with reddish scales, 

 and that we have to do with the form mentioned by Barrett as "suffused with reddish-grey". — A more 

 striking form, figured by Schwarz ("Beitrage" vol. 2, pi. 3, fig. 1 — 2), has the ground-colour changed to a flavescens. 

 decided yellow, ab. flavescens ab. nov.; Barrett mentions a similar example. — Hybr. pendulo-orbicula Tutt, pendulo- 

 obtained by Head from the crossing of pendularia cf with orbicularia ¥, is described as intermediate in "' ^^ "' 

 ■ appearance between the parent forms but nearer to pendularia ; darker than normal pendularia, but not 

 nearly so coarsely dusted as orbicularia, thus somewhat recalling ab. decoraria in its less extreme forms; the 

 markings in general rather weak. Only a few examples were successfully bred, emerging as a second 

 generation; they showed scarcely any variation. — Egg elongate-oval, the surface covered with a network 

 of serpentine ridges, dividing it into very irregularly shaped cells; micropylar rosette with 8 rays; greenish 

 white when first laid, changing gradually to yellowish grey blotched with red. Larva very variable, red- 

 brown, purple or bright green, in the latter case with the head, legs and anal extremity some shade of red-brown ; 

 dorsal and subdorsal lines pale, the dorsal area between the latter forming, in the brown varieties, a smoky band; 

 these varieties show also conspicuous dark subdorsal marks on the first 5 abdominals. Feeds on birch, occasionally 

 also, it is said, on alder or oak. Pupa rather slender, broadened and somewhat flattened, broadest at anterior 

 extremity, tapering gradually; anterior extremity truncate, with a sharp point at each shoulder; cremaster 

 with 6 rather strong, strongly curved hooks; yellowish brown or greenish, dorsal area with grey dots arranged 

 in 4 irregular series; wing edged dorsally by a broad black line. Imago in May- June and again more 

 sparingly July-September. Seasonal dimorphism rather slight, but the second brood shows a larger percentage 

 of specimens with strong reddish suffusion, perhaps also more of the blotched specimens, parallel to second- 

 brood punctaria. Inhabits North and Central Europe, Northern and Central Italy, S.E. Russia and S. Siberia; 

 an unnamed local race, unknown to me, is said to occur in the Western Thian-Shan. 



C. orbicularia Hbn. (4n). Closely related to pendidaria, forewing with apex slightly more acute, or orbicularia. 

 even minutely produced, distal margin appreciably more convex, hindwing with distal margin slightly more 

 irregular, approaching the subcrenulate form and with an appreciable tooth at the 3^"* radial; wings much 

 more strongly and coarsely dark-dusted, the course of the lines more irregular, the median shade (which is 

 seldom wanting) strongly dentate, or jagged, the postmedian dots (or dashes) more out of ahgnment, indicating 

 more definite curves of the line proximad between the radials and in the submedian area and distad at the 

 3"* radial to P' median; discal spots oftener small, particularly that of the forewing (but variable in both 

 species). Under surface similarly darker, the postmedian line on an average less well expressed. — ab. 

 namurcensis Lambill. is uniformly blackish grey, tinged with reddish in the middle, almost exactly as in the namur- 

 middle, almost exactly as in the most extreme form of pendularia ab decoraria, though considerably darker 

 and less variegated than in average examples of that form. The two narrow pale bands usually remain 

 conspicuous, but in one extreme specimen bred in England even these are almost obliterated and the only 

 conspicuous pale marking remaining is the discal spot of the hindwing. In any case ab. namurcensis can be 

 distinguished from ab. decoraria by the shape of the wings and nearly always by the course of the postmedian 

 line; Snellen referred to these points in describing (without a name) the type-specimen of namurcensis, which 

 moreover was bred from a larva found feeding on sallow, and Rebel must have overlooked this evidence 

 when he referred it to the wrong species. Unfortunately the characteristic jagged median shade is lost in 

 these melanotic forms. Lambillion's type was bred at Namur. No other examples were known until quite 

 recently, when Mr. W. H. Harwood bred some, in England, also from sallow larvae and even blacker than 

 the type, the thorax also darkened, which was scarcely the case in that. — hybr. orbiculo-pendula Tutt. orbiculo- 

 In June 1902 H. W. Head obtained a pairing of orbicularia cf with pendularia ?, which resulted in a good 

 batch of fertile ova. Four or five dozen moths emerged, all in July-August the same year. They were very 

 similar to the cf parent, only slightly paler, less coarsely dusted, more uniform; the reduction of the reddish 

 median band and in part the course of the lines gave them, however, some aspect of their relationship to 

 pendularia. — hybr. brightoni Tutt. This hybrid was obtained as long ago as 1859, from a pairing of hrightoni. 

 orbicularia cf with linearia ?, by H. Cooke of Brighton, and received from Tutt in 1905 the strangely- 



