230 BRiTISH LEPIDOPTERA. 



also there is great variability of colour, but, although each particular 

 character is subject to fluctuation, the individuals of the same brood 

 show but little variation among themselves.* ... I cannot assert 

 that a fifth moult occurs in the last 10 days, although I am very 

 doubtful whether this is the case. It is certain, however, that some 

 time before pupation, and whilst the larva is still feeding, the striking 

 colours fade out, and become replaced chiefly by black. The onto- 

 geny of this species is obviously but a very incomplete representation 

 of its phyletic development. This is at once apparent from the large 

 gap between the ist and 2nd stages. It is not possible that a row of 

 ring-spots can have arisen suddenly ; in all probability they have been 

 developed from a subdorsal line which, in euphorbiae, is now only in- 

 dicated in the second stage by a faint line. This conjecture is raised 

 to a certainty when we call in the aid of the larvae of the remaining 

 Deilephilid species (Weismann, Studies in Theory of Descent, pp. 202 — 

 207). 



Cocoon. — The cocoons are of a very firm texture, spun with 

 strong and coarse silk threads attached to some leaves of spurge 

 above, and with some sand interwoven, and, in each instance, firmly 

 fastened to the side of the pot in which the larvae have been placed, 

 and sunk about -|in. below the surface of the sand, so as to be 

 immovable, though the sand was loose. The interior of the 

 cocoons beautifully smooth, with fine silken lining (Buckler). The 

 larvae make a hole about -|in. deep, "roofing"' and "walling" it 

 with silk, mixed with sand, bits of leaves, etc., but without making 

 a distinct floor. They remain in the cocoons about a week before 

 turning to pupae. In spite of the normal habit of the larva to make 

 its cocoon partially underground, many individuals made up their 

 cocoons on the surface among leaves (when earth was not available), 

 the silk used being dark yellow in tint (Harrison). When fullfed 

 the larva enters the ground in which it makes a cocoon in which to 

 pupate (Reaumur). Cocoons are sometimes found in nature in Malta, 

 among rubbish on the ground, the larvae spinning the materials tightly 

 together (Mathew) ; larvae pupate on the surface of the ground either 

 free or in a loose cocoon (Bartel). The larvae pupate under moss, &c., 

 placed in the breeding-cage, and choose the darkest places that 

 can be found (Sich). Thirteen larvae formed loose cocoons in 

 sand (Fry). The larvae pupate in the sand, forming a loose case 

 of earth around them (Curtis). The cocoons are found just below 

 the surface of the ground (Johnson). 



Pupa. — The pupae of Hyles euphorbiae and Celerio gallii are 

 extremely similar. As compared with our other British species, 

 they agree with Theretrd porcellus and Eumorpha c/pcnor, in general 

 outline and in the anterior position of the labrum, more than 

 with any others. They are, however, less specialised than those of 

 T. porcellus , E. clpcnor, &c, in so far that the latter has an appreciable 

 keel to the maxillae, whilst in 11. euphorbiae the head extremity of 

 the pupa is fairly rounded on all aspects, and, in fact, except that the 



*Upon this fact obviously depends the statement of that extremely accurate 

 observer Roesel, that the larva of euphorbiae is but very slightly variable (Insekten- 

 belustigungen, iii., p. 36). I formerly held the same opinion; till I convinced myself 

 that this species is very constant in some localities but very variable in others. It 

 appears that local influences make the larva variable (Weismann). 



