NOTES TOWARDS A LIFE-HISTORY OF THESTOR BALLUS. 259 



buL largely as an effect of shading, this line seems to be depressed, its 

 colour is purplish-red. Below this to the flange the hue is of a flesh- 

 colour, with tendency to yellow around and above spiracles. Below 

 the flange, flesh-colour all round, the lower surface also, a little paler 

 at prolegs. Head and true legs black, except labial and maxillary 

 regions. The hairs, black and white, are long and numerous, and give 

 a darker aspect to the larva in its general appearance than the actual 

 skin-colours produce. The very spiculate hairs are now more regularly 

 distributed ; over each of the dorsal bosses are about twenty-four hairs, 

 the central rather the larger, the marginal a little smaller, and elsewhere 

 the distribution is of fairly equal- sized hairs, but smaller at margin of 

 segments. No very definite relative distribution of black and white 

 hairs is determined, but possibly exists. The lenticles are now very 

 small, about the size of the hair-bases or much less, and some of them 

 are so far related to hairs as to have rounded instead of flat centres. 

 Their distribution is irregular, not being even symmetrical, each seg- 

 ment generally has one on each side of the dorsal line in front, and one 

 or two after, laterally they are rather numerous, and on the 7th and 8th 

 abdominal segments they are quite crowded. The prolegs have a very 

 curious and elaborate structure, which was, in a slight degree, present in 

 the previous skin. The three sets of hooks already described still exist. 

 Each of the two inner sets now consists of seven or eight hooks, of which 

 several are very large, but the two sets form an arrangement similar 

 to the one-sided macro-proleg ; they are separated from each other by a 

 little space. Just outside this space or notch, and overlapping it, and, 

 in some degree, the hooks of the two sets when the hooks and leg 

 are in action {i.e., holding on), is a tall fleshy process, tall by being on 

 a short pedicel, and terminating in a retractile margin, just like either 

 of the sets of hooks, except that it is fleshy only, with a sharp margin, 

 but no hooks. The third set of hooks is still represented by two (one 

 or three sometimes) black chitinous points. The hairs, and this is 

 most conspicuous in the dark hairs, are still on a raised base, but this 

 is now comparatively small and short, is, in fact, little difierent from 

 the ordinary hair-base, a small hemispherical eminence, except that it 

 is colourless, i.e., not brown or black, with the curious exception that 

 seven or eight fine black lines, not apparently superficial, radiate to 

 its margin from the actual hair (pi. xiii., fig. 6). 



May 27th, apparently still in fourth skin, but much larger; 9*8mm. 

 long, and 2-6mm. wide ; nearly 11mm. long Avhen stretched. Whether 

 stretched or at rest, the hollow of the prothoracic plate is remarkable, as 

 is also the flat dark dorsal surface of the 7th, 8th, and 9th abdominal 

 segments. The 7th and 8th look like one large segment, the latej'al in- 

 cision between the two being slight, compared with the deep incision 

 and rounded fullness of the segments m front, when seen from above. 

 The larva is very richly coloured — bright yellow, with rich red-brown 

 and (nearly) black. The dorsal line looks nearly black, but is really deep 

 chocolate. The oblique lines are nearly as dark dorsally, ventrally they 

 get paler, and fade out a little at their lower margin. The white below 

 them makes the darker shade in which the spiracles are, seem to be a 

 second oblique line, and there is the subspiracular red or chocolate line. 

 The 7th, 8th, and 9th have bright yellow margins invaded by red, a 

 little in 7th, and a good deal in 8th. On the 7th, the yellow dorsal area 

 (of the segment) is reduced to a small white area, which is still less on 



