SPHINX LIGUSTRI. 313 



recognisable, together with the line of which they form part. The 

 7th stripe is continuous, and so also are the central parts of the others 

 where the purple border is present. The latter varies in amount 

 and I have seen it almost absent except on the 1st and 7th stripes. 

 Immediately after ecdysis the dots of the stripes are separate (fig. 

 9 x 4). The stripes are pure white where they are bordered with 

 purple, but yellowish above this part, while the purple gives place to 

 dark green. The purple and pure white change to the other colours 

 before reaching the posterior limits of the segment they are crossing, 

 while in the 5th stage the change takes place in the next segment, 

 posteriorly. The white stripes are continued inferiorly and anteriorly 

 into a very distinct row of white tubercles on the next segment, 

 anteriorly (as in the adult). The ground-colour of the part of the 

 surface on which the oblique stripes run (except the inferior con- 

 tinuations just mentioned) is a much brighter and yellower green 

 than the rest of the body. The upper yellowish part of the oblique 

 stripes is formed of distinct and separate yellow tubercles. This is the 

 stage of the "Sphinx" attitude and the head is held higher and 

 further back than at any other time. As the larva approaches the 

 end of the stage it becomes very adult-looking, this effect being 

 especially produced by the shagreen-dots becoming less conspicuous. 

 There is great variation in the darkness of the larvae, the dark forms 

 having black sides to the head, while the purple borders deepen 

 anteriorly and inferiorly into very nearly black. The lightest larvae 

 have hardly any black on the head, and the purple only deepens 

 to brownish. There is every shade of difference between these 

 extremes. A fullgrown larva in this stage is about 33mm. long 

 in the "Sphinx" attitude, but much longer when extended (see 

 fig. 5, rather over natural size). This stage lasts about 6 days. 

 Fifth ins tar : At the beginning of this stage the larva is about 33mm. 

 long when at rest in rather a contracted state after the effort of 

 ecdysis. This is the last stage, and the larva is, of course, wellknown, 

 nevertheless, there are some extremely interesting facts about it 

 especially that concerning the change from a shagreened to a very smooth 

 larva. Immediately after ecdysis the body is shagreened all over with 

 minute dots which still terminate in hairs (see plate vii., fig. 6, natural 

 size), and I formerly suggested (in paper already referred to) that the 

 row of white dots continued anteriorly and inferiorly from the white 

 stripes were the remnants of the shagreen-dots. This is now certain, 

 for they have been traced through the ontogeny *, and, further, even 

 in this stage, each one of them terminates in a minute hair, which 

 is retained to the end. The shagreening very quickly disappears, 

 but it can be detected with a powerful lens, and always remains visible 

 (though very minute) upon the undersurface of the body. Although 

 the horn is so smooth and shining in this stage, traces of the 

 tubercles can still be made out. The 8th stripe is always present 

 after ecdysis, but it quickly disappears. The deep black of the 

 horn and sides of the head are replaced by dark green after ecdysis, 

 but the latter darkens in a few hours. The shagreening seems to 

 disappear by a change of colour into that of the surrounding ground- 

 colour, and a gradual disappearance of the raised eminence which 

 forms each dot. There is the same variability in darkness as shown 



* It must not be forgotten that they are not present in the 1st instar. 



