SMER1NTHUS HYBR. HYBRIDUS. 455 



forelegs (in one larva the third pair also) ; I did not note any- 

 marked preference for either the upright or hanging position in 

 this stage, but one larva assumed a rather marked " Sphinx " 

 posture, very like that of Sphinx ligustri.] A careful examination 

 of the larva proves it to be curiously midway between the parent 

 species as regards most of the important differentiating characters. 

 In coloration and shape it is neither so white a green nor so graceful 

 in form as the larva of S. ocellata, nor is it so yellow-green and 

 heavy-looking as the larva of A. populi. Looked at in a less 

 critical manner, and without the aid of a glass, it reminds one 

 most of the yellow form of 6 1 . ocellata. Its habits and position 

 also show rather more trace of the $ than 2 parent. The fact 

 of the i st pair of oblique stripes being no stronger than 

 the 2nd" to 6th pairs, and weaker than the 7th, still further adds 

 to its resemblance to ^S. ocellata. Third stadium (July 8th) : Head : 

 as before, nearly midway between the parent forms in shape, &c, 

 but it now resembles A. populi more nearly than S. ocellata in 

 size, colour and roughness, being covered with yellowish mammillae, 

 which are only very small in the larva of S. ocellata ; the large 

 apical points are only slightly larger than in the larva of A. 

 populi, with which they agree as regards colour (yellow) ; they are, 

 however, situated, as in 6\ ocellata, close together, and not a short 

 distance apart with two smaller ones between, as is the case in 

 the larva of A. populi. Body : becomes paler towards close of 

 this stage, though not so white as in S. ocellata. Stripes : oblique 

 stripes, as in M. tiliae and S. ocellata, 1 to 5 equal, 6 narrow and 

 weak, 7 strong and broad. The subdorsal line is faint and narrow, 

 is continued backwards to the 7th oblique, but barely noticeable 

 on thoracic segments ; a double mediodorsal stripe is faintly marked ; 

 the anus outlined with same colour as other stripes. Caudal horn : 

 long and very thick at base. Hairs : still bifid, but this character 

 is not quite so marked in the hybrid larva as in the larva of S. ocellata. 

 [Habits : the larvae rest either with the head downwards (A. populi 

 habit) or with it upright (S. ocellata position), with the first two 

 pairs of forelegs withdrawn, though not so completely as is the 

 case in S. ocellata?^ One larva is growing to a large size in this 

 stage ; it is already over one inch long, and shows no sign of an 

 approaching moult. The larva of S. ocellata, when about to moult 

 in this stage, is of about the same length as this larva now is, 

 but it is not nearly so bulky. By July 12th there were only 19 

 living larvae, three well grown in the 4th skin, the remainder mostly 

 in 3rd. They varied in colour from a yellow-green to a pale, 

 whitish sage-green, and were tolerably constant in shape, but very 

 variable in size. Fourth stadium (July 12th): Head: as previously 

 described. Body : . the 7th oblique stripe is faintly continued 

 forwards to the 3rd pair of prolegs ; the 1st oblique runs 

 forward to the prothorax. The small oblique stripes that are 

 present in A. populi, just above base of prolegs 1, 2 and 3, can 

 be faintly traced in the hybrid larva. The larvae now mostly rest 

 in the position taken by that of A. populi. Both yellowish and 

 whitish forms are present in this stage. Just after the 3rd moult 

 the yellow forms are superficially very like A. populi in its 3rd 

 skin, the only striking difference being the absence of any strengthen- 



