SOLENOBIA LICHENELLA. 177 



that the cases are about four lines in length and one line in width ; 

 their form such as M. Keaumur has described with "three almost flat 

 sides, the ventral one the widest, the two others equal ; the ridge, which 

 the latter form, runs the whole length of the dorsum, and is rounded, 

 the two lateral ridges are also rounded." De Geer adds that those of 

 his examples " had more acute ridges. The case is the widest at the 

 middle and is narrow towards the two ends, at each of which there is 

 an opening, the posterior one narrow and from this the larva ejects 

 its excrement, the anterior one large, somewhat rounded, and it is from 

 this the insect protrudes its head and anterior feet ; the direction of this 

 opening is oblique to the axis of the case," or "the contour of the 

 opening is such that it is applied to the stone, the case being slightly 

 inclined to the surface." The transverse section of the case is triangular. 

 It is composed of silk, covered externally with minute pieces of stone, 

 whilst De Geer states that they add other materials, " pieces of lichen, 

 plants, wings and legs of dead insects that they meet by chance." 

 Zeller says that "the case is nearest to that of 8. triquetrella, some- 

 what shorter, with three sharper keels, also somewhat browner and 

 more covered on the anterior (head) third, with coarser particles and 

 insect debris. Among more than twenty cases collected in an old hedge 

 were six that had the greatest likeness to those of S. pineti, except 

 that they were not quite so blackish, since the larvae had used pine- 

 lichens, for the covering of their cases. The moths, which emerged 

 in the beginning of May, from both sorts of cases, showed no diffe- 

 rences and had a snow-white anal tuft. They began at once to push 

 their ovipositor into the open end of the larval case, inserting it by the 

 anal end of the empty pupa-case which protruded some distance." He 

 adds that Eeaumur's case cannot with certainty be referred here, 

 because he states that the lateral keels are rounded. 



Habits of Larva. — As soon as they are hatched the larvae set 

 about making their cases, detaching grains of sand and stone, and 

 little fragments of lichen from the old cases of their parents, and so 

 build small cylindrical cases, but clumsy and irregular and without 

 definite figure. The larva? walk with the head and anterior part of the 

 body out of the opening of the case (De Geer). They feed up slowly but 

 continuously until the autumn, when they appear to be almost or quite 

 full-fed, but very little is known of the larval habits until they appear 

 in some abundance on the rocks, walls, &c, in their special habitats in 

 early spring. That they are very secretive when feeding is evident, and 

 De Geer has noticed that larvae that fed up on the lichens growing on 

 a wall made of granite blocks leading to his house, left the wall in 

 autumn and spring and climbed the walls of his house for the purposes 

 of hybernation and pupation. 



Larva. — The newly-hatched larva is l-50mm. in length and '40mm. 

 in its widest part. The head, thorax and legs are brown, the abdomen 

 white. The head and thorax are large compared with the abdomen, 

 and comprise almost one-half the length of the larva, and as regards 

 bulk form at least one-half. A distinct constriction occurs dorsally 

 between the thorax and abdomen. The legs are very strong and power- 

 ful-looking. The prolegs are small, and the anal prolegs have a more 

 complete circle of hooks than have those of the adult larva or the Macro- 

 Psychids. The prothorax is about equal to three abdominal segments 

 from front to back, the mesothorax about equal to two, whilst the 



