AGRIUS CONVOLVULL 363 



varieties of stage i do not contrast with the light varieties of 

 the same stage in the same marked manner as the two varieties of 

 stage 4 contrast together ; nevertheless, the two varieties of the former 

 were very different in this respect, and we should have expected that 

 the darker larvae exhibited traces of the darkness which became more 

 manifest in later stages. So also we might well have supposed that 

 the single larva which exhibited marked indications of the dark borders 

 in stage 2, would have been among the number of those in which 

 the character was principally developed in the next stage instead 

 of among those in which it was least developed. It is well known 

 that the green form of these larvae often persists into the last stage. 

 Thus I was assured that this variety is commoner than the other 

 in the Canary Islands and in Madeira. In the larvae above-described 

 it has been seen that three individuals retained the green ground- 

 colour " in the 4th stage, while all the others lost it. Under 

 these circumstances, it might well have been supposed that 

 the larvae would exhibit the power of variable protective 

 resemblance which so many species are now known to possess. 

 Thus Rutnia crataegata can be rendered brown or greenish ; while 

 greater or less variation in the depth of the brown ground colour 

 can be caused in Crocallis elinguaria, En?wmos angular ia, 

 Selenia lunaria, Boarmia rhomboidaria, B. roboraria, Catocala sftonsa; 

 and variations in the green colour of Smerinthns ocellatus and 

 Sphinx ligustri. Other instances occur, and this power is doubtless 

 very widely spread among larvae. It is, however, certain that 

 S. convolvuli does not possess this power in any marked degree, 

 and it is probably entirely wanting. My larvae were fed in glass 

 cylinders placed upon white plates, and the food was always kept 

 green and fresh. Only in the last stage were brown surroundings 

 (earth and dead leaves) introduced, in order to test the opinion 

 that the larvae conceal themselves. The complete absence of brown 

 surroundings in the earlier stages would have produced light brown 

 or green individuals of nearly all the species above-mentioned, 

 and yet the convolvuli larvae became exceptionally dark. It is, 

 therefore, probable that the predominance of dark varieties in one 

 locality, and green in another, is due to the ordinary operation 

 of natural selection upon the two forms of a dimorphic species, 

 tending to exterminate a relatively larger number of the variety 

 which harmonises less with the surroundings in each locality" 

 (Trans. Ent. Soc. London, 1888, pp. 551-553). Burrows notes (Ent. 

 Bee, xiii., p. 306) a larva, from Mucking, of a bright, pale green 

 colour, vertical lines white, horn orange, and spiracles orange ringed 

 with black. Anal flap and anal prolegs yellow. Every segment 

 transversely lined narrowly in black, corresponding with the sub- 

 segmental divisions. Five larvae — 3 brown and 2 green — taken wild 

 in 1 90 1, at Monkton, are described in the E.M.M., xxxvii., pp. 

 2 57 _2 5^. A larva with an entire absence of oblique lateral 

 stripes is described by Newman (Entom., viii., pp. 272-274). 

 Pearson notes the capture of a larva at Chilwell, which had 

 no black markings except a large black spot round the spiracles 

 and stripes down the face ; the general colour being dull apple- 

 green, the horn reddish with a black tip. 



Puparium. — Sturt, who reared this species successfully in 1895, 



