52 BRITISH LEPIDOPTERA. 



ency for the males to have the nervures pale in the outer marginal 

 areas, and in the $ s this is often extended to the nervures of the 

 inner half of the wing. There is considerable difference in both 

 sexes in the size of the central white spot of the forewings, and in 

 the £ s this is frequently surrounded by a very dark rim, which 

 makes it exceedingly conspicuous. The variation in the width of 

 the transverse band has led to considerable difficulty with the 

 named forms ; this has been especially so with regard to the form 

 named roboris by an anonymous writer (Dr. F. J. A. D.) in the 

 Rhein. Magazin, in 1793, and discussed later. Esper described 

 (Sehmett. Eur., iii., p. 81) two forms occurring in central Europe: 

 (1) With the transverse bands narrow and restricted (? = ab. 

 spartii, Hb.). (2) With the outer edge of the transverse bands 

 extending towards the margin of the wing and encroaching on 

 the ground colour. This latter form Dr. F. J. A. D. (Rhein. 

 Mag., i., p. 362) named roboris, and in this was followed by 

 Schrank. Much still remains to be learned with regard to the 

 Sicilian, southern Italian, and Spanish forms of the species, most of 

 the literature relating thereto being very unsatisfactory, and it is 

 difficult to determine from the published facts at disposal exactly 

 what forms are obtained in Sicily. Mina - Palumbo and Failla- 

 Tedaldi write (JVat. Sic, vii., p. 231 (331 by error)) : " Bombyx quercus 

 occurs from June to September ; the type form has been met with by 

 Ghiliani, Mann, and Zeller. The var. spartii is more frequent, and 

 occurs from September to November. It is darker, with a straight 

 yellow fascia on all the wings, and has been recorded by Bellier, 

 Mann, and Zeller, Bellier making it a distinct species on account 

 of the alleged different colour of the antennae, which, however 

 we are not able to distinguish, nor does the character appear 

 to be sufficiently important for the erection of a species. The var. 

 sicula is the dominant form. The var. roboris, Schr., also occurs, 

 this form being larger, with the yellow fascia of the anterior wings 

 broader." We suspect by spartii these authors really mean var. 

 viburni or var. meridionalis, whilst their description of roboris applies 

 well enough to this form so far as the transverse band is concerned. 

 We do not know, however, whether the russet colour of var. sicula 

 is found in the other forms were mentioned, or whether these agree in 

 ground colour with the dark chestnut-brown of true var. meridionalis, 

 ab. roboris, &c. The British examples tend much to local races. 

 The males from Potton are not unlike the ab. spartii, figured by 

 Hiibner, from Germany, but have a slightly wider band and a faint 

 yellow shade that spreads as it were from the middle portion of the 

 transverse bands on fore- and hindwings, suffusing and narrowing 

 the outer marginal areas, and destroying the striking contrast so 

 observable in var. meridionalis, in this respect rather approaching 

 var. viburni. The females are distinctly different inasmuch as the 

 fore- and hindwings are of the same reddish-ochreous tint that 

 characterises only the hindwings of the French races, and the band 

 on the hindwings inclines to obsolescence and tends to blend with the 

 ground colour of (he marginal area. The white median spot of the 

 forewings is distinctly larger, whiter, and not ringed so darkly. 

 This tendency to the spread of the yellow of the bands on both fore- 

 and hindwings, in the males from Cambridge and other British 



