lepidoptcrous larva and pupa. 



145 



lateral white streaks, bordered above with lilac." 

 Certainly this correlation of the markings of the two 

 larvffi seems sufticiently obvious, and is the one which is 

 also given in other descriptive works. Recent investi- 

 gations, however, have shown the relations existing 

 between the oblique stripes and their coloured borders 

 (by a comparison of the ontogenies of SmerinthiLs and 

 Sphinx larva3). The conclusions arrived at by these 

 investigations suggested a careful examination of the 

 position of the violet bands of A. atropos, which resulted 

 in the proof that these markings do not correspond to 

 the stripes of S. Ugiistri, but to the coloured borders 

 only,— the latter markings, in fact, have persisted, while 

 the oblique stripes have become inconspicuous. This 

 correspondence is at once seen on comparing the relative 

 positions of the caudal horn and the spiracles to the 

 oblique markings in .1. atropos and S. lignstri respectively. 

 The fact is recognised by Weismann on p. 322 of the 

 English translation of his work, where he speaks of the 

 blue "edges" of A. atropos, and compares them with 

 those of S. ligustri, &c. The stripes are also present 

 in A. atropos, but, being only of a hghter yellow than the 

 rest of the ground colour, they are easily passed over. 

 They are narrow in the lower half of their length, 

 becoming broad above, so that they occupy very nearly 

 the whole interval between the coloured borders in the 

 dorsal region. This broadening takes place as each 

 stripe crosses the furrow which separates the two 

 segments in which its course lies. In S. ligustri the 

 ground colour is much brighter in the region of the 

 oblique stripes and borders than elsewhere ; in ^. atropos 

 this is probably also the case, but the brightened ground 

 colour cannot, of course, be distinguished from the true 

 oblique stripes (which are also brightened ground colour). 

 Hence what is described above as a broadening of the 

 oblique stripes may in reality be due to their fusion with 

 another of the elements of larval colour. The brightness 

 of the ground colour in the region of the oblique 

 markings, due in part to stripes and in part to the 

 ground colour itself, produces an effect which is very 

 like that of S. ligustri. Below this region the ground 

 colour becomes much darker and greener in both larvae, 

 and in both the darkened colour spreads upwards in 

 front of the borders for the lower half of their length. 



