4^2 feRLTISH LEPID0PTER.A. 



APPENDIX 



Mimas tilim, Linnd (Vol. iii., p. 399). 



[Page 411.] Development of the markings of the larva of 

 Mimas tili^e. — First instar : The young larvae emerge after an 

 oval period of 14 days ; they are of a light green colour, are 

 conspicuous for the great length of the caudal horn (which is nearly 

 half as long as the body) ; this horn is likewise of a light green tint 

 at first, but becomes dark violet in the course of an hour ; no trace 

 of markings can be detected at this stage. The larvae rest on the largest 

 vein on the underside of the lime leaves, and, in this situation, 

 have the same form and colour as the leaf vein. They moult in 

 from 4-5 days. Second instar: On each side of the segments 4-1 1, 

 there now appear 7 oblique whitish stripes on a somewhat darker 

 green ground ; these slope in the direction of the caudal horn ; 

 owing to the transparency of the skin, a dark green dorsal line 

 appears in the position of the underlying dorsal vessel, the green 

 contents of the alimentary canal being distinctly visible through 

 the absence of adipose matter in the tissues ; the larvae possess also 

 a fine whitish subdorsal line, which extends from the horn to the 

 head ; the horn at this stage becomes black with a yellowish-red 

 base. In 6 or 7 days the second moult takes place. Third instar : 

 The oblique stripes now appear darker and the subdorsal line 

 disappears. The third moult takes place after another period 

 of 4 or 5 days. Fourth instar: There now commences a dimorphism 

 (better perhaps designated as variability since the two extremes 

 are connected by transitional forms) in the larvae. (1) The 

 majority of the larvae have, as in the preceding stage, pure white, 

 oblique stripes. (2) Many, however, possess a blood-red spot 

 on the anterior side of the stripes, this spot showing all gradations 

 in size and depth of colour between maximum development and 

 a mere trace. Fifth instar: In this, the last stage, the red spots 

 become more strongly pronounced. Among 80 caterpillars from 

 one brood there were about 20 without any red, whilst the remainder 

 were ornamented with more or less vivid blood-red spots, often 

 large and irregular in form ; in some specimens the spots had become 

 drawn out into lines (this variety is figured by Rosel) forming a 

 coloured edge to the oblique white stripes, similar to that possessed 

 by the larva of Sphinx ligustri. The caterpillar is thus represented 

 in many figures, but generally the coloured stripe is made too 

 regular, as, in reality, it is always irregularly defined above, and 

 never so sharp and even as in Sphinx ligustri. The character is 

 here obviously not yet perfected, but is still in a state of development 

 (Weismann, Studies in the Theory of Descent, transl., pp. 233-236). 



Smerinthus ocellata, Linne' (Vol. iii., p. 424). 



[Page 436.] Development of the markings of the larva of 

 Smerinthus ocellata. — First instar: The newly-hatched larvae are 



