HA RD WICKE ' S SCIENCE-GOSSIP. 



39 



precisely to that of the other four members of this 

 genus, to which the popular epithet of "kittens" 

 is usually given on the frail and far-fetched basis 

 that they are " like the puss, but smaller ! " 



The eggs of D. vinula are generally laid in batches 

 of two together, but occasionally singly, and more 

 rarely four or even five may be found on one leaf. 

 They are always laid on the upper side of the leaf, 

 and are usually of a red-brown colour, but are some- 

 times found all hues, ranging from the above red- 

 brown to a creamy-white. At first I thought that 

 the whitish variety was probably due to infertility, 

 but subsequently discovered it to be invariably fertile, 

 and, contrary to the observations of the zoologist's 

 correspondent, mentioned in Newman's " British 

 Moths," the young larvae emerging from them in no 

 way differing from the general — I may say invariable 

 — type. The egg is rather a large one for the size of 

 the imago. I have found it on various kinds of 

 rPopuhts and Salix, but by far more frequently on the 

 'former, as, for instance, P. tremula, nigra, balsami- 

 fera, and a species which, I believe, is not in- 

 digenous to this country, and grows very similarly to 

 the "weeping willow," although not so tall. On 

 this latter I have also taken the empty pupa-case of 

 Leucoma salicis. The period of oviposition extends 

 over a considerable length of time, commencing, 

 provided the weather be normal, soon after the 

 middle of May, and continuing till the end of June 

 or beginning of July. The earliest eggs I have ever 

 found were on the 13th of June, but since the ecdysis of 

 the imago occurs about the 12th of May, and they 

 pair almost immediately, eggs must be about by the 

 25th of May at the latest, and may be found through- 

 out the remainder of that month, the whole of June, 

 and beginning of July ; the latest eggs I ever saw 

 being July 9th, but at that late date they are almost 

 invariably taken singly. The eggs are occasionally 

 found on old dead leaves. It is possible that the 

 parent moth may lay them there, but at the same 

 time it is by far more probable that the leaf had 

 become sere and shrivelled after being visited by the 

 female insect. In this case, of course, the young 

 larva is obliged to climb the stalk and find a fresh 

 and more nutritious leaf, before partaking of any 

 foreign food, except its empty egg-shell, which is 

 invariably devoured as soon as vacated. 



In searching for the egg, it is advisable to bear in 

 mind that if there has been anything like a breeze in 

 one direction for two or three days previously — and 

 the longer the previous duration of the fixed wind, 

 the greater one's chance of success — the ova will 

 probably be on that side of the tree farthest and most 

 sheltered from the wind. This is a natural hypo- 

 thesis, and one which I have found, when practicable, 

 almost invariable. 



The larva of D. vinicla is perhaps as interesting 

 and curious a one as is to be found among our British 

 representatives of the order Lepidoptera. When the 



little caterpillar first emerges from the egg, he is 

 about five lines in length, black and dark purple in 

 colour. The following is a description of him in all 

 his skins, taken from life. The first segment (the 

 head) is black and shiny ; the second bears the first 

 pair of legs and a pair of prominences, jagged at the 

 tips, which stand out on each side of the head, 

 strongly resembling the ears of a kitten, These 

 "ears" I consider exceedingly interesting, as it is, 

 in my opinion, in this stage, that the insect bears out 

 its popular name more than at any other. It is 

 curious that no authors of works on our Lepidoptera, 

 — except Mr. Newman, who does not appear to attach 

 much importance to it, — mention this peculiarity. 

 The third segment bears the second pair of legs ; 

 the fourth, the third pair of legs and a very slight 

 hump. The sevenih, eighth, ninth and tenth seg- 

 ments bear the four pairs of prolegs. The thirteenth 

 segment bears the fifth pair of prolegs, which are, 

 however, converted into two "horns " or tails, nearly 

 a quarter of an inch in length, which are black, with 

 yellowish threads, or tmtacula, which protrude when 

 the larva is irritated or startled. Just above these 

 horns, almost on the back, as it were, is the anal 

 orifice, and again above this is another pair of " ex- 

 ceedingly minute horns." The belly and lower half 

 of the larva is of a very dark purple, the back and 

 upper half being black. 



The second skin differs little from the first, 

 excepting in size and colour. The " ears " have 

 increased, being now about a sixteenth of an inch 

 long. The fourth segment has also developed con- 

 siderably, now having a distinct and obvious hump ; 

 at the eleventh segment the larva commences to 

 become thinner, gradually tapering off to the thir- 

 teenth segment, which is very small, and whence the 

 horns spring. The horns in this skin are about half 

 an inch in length, black mottled with yellow or red, 

 but variable, with red threads, and the minute dorsal 

 horns are still visible. The head is as above, black 

 and shiny, and the ears still jagged at their ends. A 

 strong black dorsal band extends from the ears to a 

 point on the hump on the fourth segment, and thence 

 widens to between the eighth and ninth segments, 

 where it reaches to the lateral lines, and then runs in 

 the shape of a half-moon to the eleventh segment, 

 where it is about as broad as one of the "ears" is 

 long. It then widens out again to the lateral lines 

 near the tail, and ends on the minute dorsal horns 

 before mentioned. The remainder of the body is 

 yellow (or red when just "turned" from the first 

 skin), with an exceedingly faint black lateral line 

 and the dorsal line proper is indicated by the black 

 being slightly darker along the centre of the back in 

 a narrow line. 



The third skin is almost exactly the same as the 

 second, except, of course, that the larva has again 

 increased in size, and is now five-eighths of an inch 

 in length. The only other appreciable difference is 



