122 THE entomologist's recobd. 



to like it, for they would only just nibble a little at the luscious well- 

 grown leaves with which I supplied them, and fed with avidity when- 

 ever I met with any considerably dried-up plants. When the larvaB' 

 were received I noted that many of the cases were very small, 

 and all much smaller than the examples found near London on 

 ground-ivy, which were nearly, or quite, of full size. The latter, too, 

 were much blacker than the cases of the marjoram-fed larvae, which 

 were brown. Closer examination showed that the cases were covered 

 with hairs, so that they had a hoary appearance. When I have 

 previously met with this species I had only very casually looked at the 

 case, and assumed, really without any reason, except the generally 

 smooth black appearance of the case, that it was composed wholly of 

 silk. That this, however, was not so, was most apparent from the 

 cases made by the marjoram feeders. The white, hoary appearance is 

 wholly due to the abundant hairs attached to the cuticle of the leaf^ 

 from which the case is made or enlarged. However, in confinement, 

 these cases frequently assume a smooth appearance, because other 

 larvffi bite off all these cuticle hairs. The lighter colour of the cases 

 of the marjoram feeders is due to the cuticle, when dead, becoming a 

 lighter brown than does the cuticle of ground-ivy leaves. There are 

 also lighter edges to the anal flaps, and the keel on the lower side 

 is also of a light brown. The brown of the main portion of the 

 case is made darker by the deposit of very dark blackish 

 material inside the case, which darkening, in the ground-ivy 

 feeders, shows through, and has more effect than in the marjoram, 

 feeders. All the enlargements are made in a most clever manner,, 

 so that it is very difficult to see where the new portion is joined 

 to the old, and the case has a very uniform appearance through- 

 out. However, I did see slovenly larvae, which only roughly enlarged 

 their habitations, but probably they were weak, ill-nourished, because 

 they would only eat of the hard coarse kind of marjoram referred to 

 above. When a larva wishes to enlarge its case, it fixes it, not on the 

 surface of a leaf, but on the edge, so that the back keel is in a straight 

 line with the margin. Then it commences to mine, and, having eaten 

 out an area sufficiently for its purpose, it bites oft' the portion of leaf, 

 fastens it up where necessary, and walks off to finish its task. Thus 

 one side of the leaf piece, forms one side of the case, and the other the 

 other side ; and whatever difference there may be in the upper- and 

 undersides of the leaf used, is apparent in the completed case. The 

 description of the larva made reads as follows : — 



The colour of tlie plates of the head and prothorax is light brown. The second 

 thoracic segment has two black plates separated from front to back by a narrow 

 suture and pointed exteriorly. The metathorax is very similar, but the 

 plates are slightly smaller, and the suture between is wider. All thi'ee segments 

 have small black plates on the sides, those on the mesothorax being slightly the 



I saw one larva on May 23rd, cut himself off after enlargement. 

 The back, near the head, was first severed, then it worked along the 

 lower side from both ends alternately towards the middle. As soon as 

 it was ready, the mouth end was fastened securely with silk, while the 

 rest of the cutting off' and closing up was carried out. All but one 

 larva finished feeding by May 30th, and imagines were bred at the 

 beginning of July. 



