STRYM0N PRUNI. 197 



forewings, and two or three fulvous patches only on the hindwings, 

 is the Linnean type. The various stages may be grouped as : 



(1) Forewings unicolorous, hindwings with two or three fulvous patches = 



pruni, L. 



(2) Forewings with two or three fulvous patches, as in the hindwings = ab. 



progressa, n. ab. 



(3) Forewings with four or five fulvous patches, as in the hindwings = ab. 



excessa, n. ab. 



(4) Forewings with wide fulvous patches, crossing through as a complete band 



(broken only by nervures) ; the hindwings with a similar band = ab. 

 ptorsas, Hufn. 



(5) The wings faintly suffused all over with fulvous, spreading from the usual 



fulvous patches = ab. fulvior, n. ab. 



The patches also show considerable difference in depth of colour, some 

 inclining more distinctly to orange, others to yellow = ab. lutea. With 

 regard to this spotting there are several notes, e.g., Knatz records one 

 in which the orange lunules, towards the anal angle of the hindwings, 

 are altogether wanting (Ent. Zeits. Guben, i., p. 5) = ab. obsoleta, n.ab. 

 Wheeler observes (Butts, of Switz., p. 50) that, in Switzerland, the 

 $ has generally two or three spots on the upperside of the hindwings, 

 and none on the forewings, the $ three to five on the hindwings, and 

 two or three on the forewings. Raynor observes (in litt.) that " he 

 has two 2 s (bred from larvae taken at Monk's Wood, 1901) in which 

 the three orange blotches along the lower half of the outer margin are 

 very strongly developed." Buhl observes (Pal. Gross- Schmett., p. 183) 

 that " the $ generally has, on the outer edge of the forewings, between 

 nervures 1-3, a row of two to three very faint rusty-red spots, which 

 sometimes, however, are missing ; in the $ , however, these spots 

 always show as a reddish -yellow marginal border, which is divided 

 into spots by the very pronounced black nervures. The hindwings of 

 the $ often show only the outline of an antemarginal stripe, formed 

 of small, rusty-red crescents, which generally extends only from one- 

 half to two-thirds along the outer border, and never reaches the costa ; 

 one to three delicate blue dots can be seen in the black margin, near 

 the finely blue-bordered tail; the antemarginal rusty-red band is much 

 larger and more pronounced in the ? , but it also, in this sex, never 

 extends to the costa." Aigner-Abafi says that, in the Hungarian 

 specimens, the rust-coloured marginal spots usually hardly noticeable 

 in the J , are also sometimes quite absent in the $ . He further notes 

 that the ground colour of the underside of the examples taken in Hungary 

 is often nearly as yellow-brown as is that of Ruralis betulae, the red 

 hind-marginal band in most specimens being brightly coloured (in 

 litt.). There is also considerable variation in size. Ash observes that 

 some examples that he bred from larvae in 1901 were exceedingly 

 small, and there is a marked tendency for specimens reared in confine- 

 ment to be of small size, unless provided with an abundant supply of 

 fresh food. We would call examples less than 25mm. in expanse ab. 

 minor, n. ab., and those above 32mm. ab. major, n. ab. Keynes 

 observes that the specimens that he captured near Lahr, in June, 

 1906, were not only larger than English ones, but had a great deal 

 more orange on the forewings. Nolcken states that the examples from 

 the Baltic Provinces are larger than a pair from north France, 

 although, otherwise, they do not vary from them, except that the 

 French ? has the ground colour of the underside of a lighter and 



