268 BRITISH LEPIDOPTERA. 



able variation. Thus the newly-hatched larva of Ceratomia amyntor 

 is described by Fernald ( Sphingidae of New England, p. 115) as 

 having a pair of minute thoracic horns on the top of the 3rd segment 

 and another pair on the top of the 4th, whilst there is a row of 

 minute fleshy teeth along the middle of the back, which are scarcely 

 visible. Like many of the higher Sphinginae, it develops its 

 characteristic markings before the 1st moult, and assumes its 

 covering of secondary shagreen-hairs at the first ecdysis, this 

 latter it retains until adult, and, when fullgrown, " has" a dorsal 

 row of fleshy teeth, one on each wrinkle, tipped with whitish or 

 pink, extending from the 4th segment to the caudal horn ; there 

 is also a pair of short straight tuberculated horns on the top of 

 the 3rd segment and a similar pair on the 4th. 



As to the larval markings, Weismann has attempted to discuss 

 them (Studies in the Theory of Descent, pp. 259 et sea. J but he 

 is wanting entirely in first-hand knowledge, except in the case of 

 Hyloicus pinastri, a species that, in the larval stage, is very different 

 from the characteristic type of the subfamily, but, on the strength 

 of the figures of certain species (already detailed, anted, p. 266), he 

 concludes that the subdorsal line was the primary marking, this 

 line being subsequently entirely replaced by the oblique stripes. 

 He further suggests that the Sphinginae are a younger group than 

 the Amorphinae, a conclusion which he considers, as we have also 

 already noted, to be borne out by the fact that, in the former, 

 the oblique stripes have reached a higher- development, being always 

 of two, and sometimes even of three colours (Sphinx drupiferariim — 

 white, red, black), whilst, in the Amorphids, they only occasionally 

 possess uniformly coloured borders. Weismann's work with regard 

 to the markings of the Amorphid larva (loc. cit., pp. 232 et sea.) is 

 more satisfactory, but much detail is missed, and only the broadest 

 general features are discussed, whilst his conclusions, with regard 

 to the adaptive nature of the markings (loc. cit., pp. 320 et sea. J, 

 are probably as correct as anything since formulated. Poulton, 

 who followed up this line of enquiry, made a number of detailed 

 observations (some of which are, unfortunately, not quite accurate) 

 which were published between 1884 and 1888 *. In his first 

 paper, he utilised Weismann's remarks on the part played by the 

 modification of the shagreen-spots in the formation of the prominent 

 pale markings in certain Phryxid larvae, so far as to apply them 

 to the formation of the characteristic Sphingid and Amorphid markings, 

 and to show that the oblique lines of the Amorphid larvae originated as 

 enlargements of the shagreen-dots, and that the effect has been 

 increased by the ground-colour becoming gradually lighter along 

 the same lines (Trans. Ent. Soc. Lond., 1884, p. 32). He further 

 notes (loc. cit., p. 36) that the shagreening in the larva of Sphinx 

 ligustri is exactly like that of the Amorphid larvae, and states that, 

 in the last stadium, the white stripes of the former retain indications 

 of the shagreen-spots on their anterior inferior extremities, which 



* (1) Trans. Ent. Soc. London, 1884, pp. 27 et seq. (2) lor. cit., 1885, 

 pp. 281 et seq. (3) Proc. Roy. Soc. Lond.. xl., pp. 135-173. (4) Trans. Ent. Soc. 

 Loud., i$86, pp. i37-i 79- (5) loc > c **-> IlS8 7, PP- 281-321. (6) loc. cit., 1888, 

 pp. 515 et seq. 



