CHAP, xii.] LARV.E OF SPHINGID^E. 305 



whole, shewing only slight differences in tint in different parts of the 

 body. To this there are certain exceptions, of which A. atropos is 

 especially remarkable. In the brown variety of this species the 

 abdominal segments have a dark ground-colour composed of shades 

 of brown, while the three thoracic segments in it are white "like linen" 

 (see WILSON, PI. vi.; BUCKLER, PI. xxi.; POULTON, 1886, p. 149; 

 HAMMOND, Zool., 6282; BALDING, Ent. Mo. Mag. xxn. p. 279; GIRAKD, 

 Bull. Soc. ent. Fr., 1865, S. 4, v. p. xlix. <fec.). 



Tn M. stellatarum though the ground-colour of the head and of all 

 the segments varies greatly it appears that the head and prothorax vary 

 in colour simultaneously with each other and are of one colour, while 

 the other two thoracic segments and the abdominal segments also vary 

 together but usually differ from the head and pro-thorax (see WEISMANN, 

 PL in.). 



In illustration of the degree to which simultaneity of Variation 

 is possible over considerable areas of the body the varieties in markings 

 are perhaps more important than those in ground-colour. Of such 

 changes simultaneously occurring in several segments there ai'e many 

 examples. 



4g5 In all the varieties of ground-colour in M. stellatarum the pattern 

 of the markings remains the same though of differing intensities 

 (WEISMANN, p. 248), but in the brown variety of A. atropos the pattern 

 is quite peculiar and cannot even be recognized as a representation of 

 the markings seen in the green form. Even the oblique stripes are 

 absent (PouLTON, 1886, p. 149; see also authors quoted above). But 

 as in the ground-colour so in the markings, the abdominal segments 

 have one new pattern while the thoracic segments have another. 



466 The figures of larvte of Deiphila euphorbia} given by BUCKLER and 

 by WEISMANN are especially interesting in this connexion, shewing 

 that in the complex variations of this polymorphic form the particular 

 pattern of the individual is carried out with little difference in each 

 segment behind the prothorax. Some of these changes are extensive, 

 but to be at all appreciated the figures must be referred to. In one 

 case all the triangles at the posterior part of each segment were red 

 instead of green as usual, and this change was found in many speci- 

 mens from one locality (see WEISMANN, p. 206, PI. v.). This identical 

 variation was known to and figured by HUBNER (WEISMANN). In 

 one specimen from the same place as the last the second row of marks 

 which should occur just below the sub-dorsal mark of each segment 

 was absent throughout the whole line, and the ring-spots of the upper or 

 sub-dorsal row had, as a variation, a red centre or nucleus, well marked 

 in the posterior spots but fading away anteriorly. The occurrence of 

 these considerable changes is still more noteworthy if, as WEISMANN 

 states, the members of each batch are much alike. He remarks also 

 that the variability is great in some localities but little in others. 



467. The larva of Deilephila hippophaes has a sub-dorsal row of red 

 markings upon a variable number of segments from the 7th abdominal 

 to the 3rd or even 2nd abdominal, increasing in size and distinctness 

 from behind forwards. The size of these markings differs greatly in 

 different specimens, varying from a mere dot to a distinct red spot 

 with a black ring. As the figures shew, there is a considerable cor- 



B. 20 



