228 [October, 



which are merely represented by minute circles, and the bhick marks are in 

 quite flexible skin and consist of the dots outlining the skin-points being black. 

 These minute points are, on the dark and pale skin, arranged in little lozenge- 

 shaped groups, in the feeding instar they are in transverse lines. The head is 

 very pale and of apparently quite soft consistence, though the mandibles are 

 almost the same as in the feeding instar, except that they have brown chitini- 

 satiou only along their dentate margin. It is difficult to suppose tbese 

 mandibles to have any function. The skin cast at pupation by Luphyrus jjini 

 in its cocoon, presents the head as a small pale flap and the skin proper as a 

 roll behind this. It is rolled up in two revolutions, the last segments being- 

 the inner ones. The skin is apparently thrust backward as it is cast, and the 

 end is rolled up in this way against tlie cup-shaped end of the cocoon. 



Larvae differ much in the state which their cast skins take up. Most 

 Lepidoptera in cocoons thrust the skin back, and it folds up, segment by seg- 

 ment, in accordion folds. Trlchiosoma, which moults to pupa under conditions 

 apparently identical with those of L. pint, has the skin disposed in the 

 Lepidopterous manner. 



Loplujrus pini is quite willing to make its cocoon on the tree and amongst 

 the pine-needles, so is probably in no need of a change in appearance, but the 

 change in structure is as deflnite as in Thymatocera or Rhudinoceraea, strongly 

 confirming the view that these changes refer to some necessities of hibernation 

 in the cocoon. 



Trichiosoma, however, whose conditions seem so similar to those of the 

 species so far discussed, makes no such moults, but spins its cocoon still in its 

 last feeding instar. 



Tfichiucampa viminalis differs a»ain. The larva when quite young is 

 green, when older and when full grown each extremity becomes orange, and 

 when it starts on its search for a pupariuui becomes entirely orange. It is, 

 however, probably orange throughout previously, and the green middle portion 

 is due to food-contents, which are absent in the smaller travelling larva, and 

 here there is no moult to produce the change of colour, which seems due to the 

 emptying of the prituae viae. The young green larva as well as the older 

 bicoloured one are very inconsi)icuous, even ranged in the ranks in which it 

 feeds ; the wholly orange one probably is a case of warning coloration or a 

 animicrv of such colouring. 



EXPLANATION OF PLATES V-VII. 

 Plate V. 



Fig. 1. — Larva of Rhadinoceraea micans King, X about 3. 



,, 2. — ,, ,, ,, „ ,, X about L. 



„ 3. — Larva oi Phymatucera dferriina Kl., X about 'li,. 



„ 4. — Skin cast by a species of Periclista on assuming the smooth covering- 

 suitable for making a puparium, X about 1^. 

 These four figures are of various enlargements, from photographs 

 kindly given me by the Rev. F. D. Morice. 



„ 5. — Photograph of portion of prepared skin of Phymatocera aterrima, 

 X 60, by Mr. F. N. Clark ; it includes a spiracle. The spiracles 

 have much the same appearance in R. micans. 



