438 Miscellaneous. 



the first of June, a remarkably brilliant, golden-winged fly settling on 

 the leaves in the hot sunshine, and darting off with great velocity on 

 being approached. This insect is one of the saw-flies {Lyda inanila), 

 a very rare British species, which we were, of course, glad to per- 

 ceive to be a native of our own locality, more especially as from its 

 regular appearance we had no doubt of ascertaining its habits ; the 

 larvae of the genus to which it belongs being the only ones in the 

 family Tenthredinidae which are destitute of the false legs along the 

 ventral parts of the body. 



The perfect insect is represented in the accompanying woodcut, 

 fig. d, rather larger than life, the extent of the real expansion of the 

 wings being indicated by the straight line (fig. e). We have un- 

 fortunately never been able to see this fly deposit its eggs, but as w T e 

 have found its larva of a very small size upon the rose-trees, we 

 have no doubt that it is upon the leaves or stems of those trees 

 that they are laid. Towards the end of June and through the month 

 of July we have observed, upon different varieties of the Rose, some 

 curious cases formed of bits of rose-leaves cut into strips, and care- 

 fully rolled up into a long cylinder, or rather a very elongated cone, 

 one end of which remains attached to the leaf, whilst from the wider 

 orifice there issued forth the head and fore-part of the body of a 

 caterpillar, which we at once recognized as that of a species of Lyda, 

 and which there can be no doubt is that of the species which we find 

 in the winged state. 



The mode in which these terrestrial caddice insects form their cases 

 is very remarkable. The larvae by degrees cut off one edge of the 

 leaf, thereby forming a strip about one-eighth of an inch wide, at the 

 same time eating a portion of the leaf immediately adjoining the slit 

 which they make. The strip of the leaf is gradually lengthened as 

 the insect proceeds upwards or downwards along the edge of the 

 leaf. Its mode of action will however be best learned by our fig. a, 

 which represents part of the. underside of a leaf with its attached 

 case and inclosed insect. One end of the strip is, in fact, rolled 

 round the insect's body (the roll being fastened by silken threads of 

 great delicacy, which the insect spins), whilst the other end of the 

 strip is only detached from the leaf when the larva has arrived at its 

 extremity. As however the insect would be very liable to the 

 attacks of ichneumon-flies and other insects, if the strip were bent 

 upwards, the insect has the singular instinct to roll it downwards, so 

 that the insect whilst feeding is entirely protected from being seen 

 from above by the part of the strip nearest to the body of the leaf, 

 seen in our fig. a, to the left of the head of the insect, the uneven 

 edge of the leaf above its head being the part from which it has 

 already detached a portion of the strip which it has wrapped round 

 its body ; it will also be seen that it has the further instinct to arrange 

 the serrated edge of the leaf outside of its case, so that wet is thrown 

 off just as by the tiles of the roof of a house. There is a still farther 

 display of instinct in the strip being rolled spirally, so as to form a 

 long case. 



The roll or case when the larva is full-grown is two inches long 



