LUFFIA LAPIDELLA. 239 



et grosse comme un grain d'orge, plus pointue d'un cote que de l'autre, 

 a peu pres comme une chauffe d'hypocras. . . . toute parsemee 

 de petites pierres et de petits oeufs verdatres ; il y a dans l'extremite la 

 plus pointue un petit trou par ou ces vers jettent leurs excremens ; et que, 

 dans l'autre extremite, il y en a un plus grand par ou ces vers passent leur 

 tete, et s'attachent a la pierre qu'ils rongent." Reaumur says that de la 

 Voye has well compared the case to a " chauffe d'hypocras, curved and 

 open at both ends." He states that the large opening from which the 

 larva protrudes its head and legs is oval in outline, and forms a plane 

 cut obliquely to the axis of the cone, so that when tbis opening is fitted 

 down on a stone, the cone stands at an angle of about 45°. The case 

 is made of silk, covered externally with an infinite number of minute 

 particles of stone. The new cases made by some larva? extracted from 

 the old cases were somewhat like a truncated cone in general appear- 

 ance. These larvae spun a certain amount of silk, and then, with the 

 jaws, picked up a minute particle of stone and attached it to the silk, 

 as the case was extended anteriorly the particles of material were added 

 to the silk. The colour of the case, he adds, is ordinarily ashy-grey, 

 but some of these new cases were covered with yellow grains, possibly 

 from morsels of lichen or stone. Voye's " greenish eggs," with whicb, 

 he says, the cases were covered, Reaumur considers, were probably little 

 scraps of moss, mixed with the stone. Two cases sent by Luff from 

 Guernsey had each a very small piece of stick attached longitudinally 

 to the case ; this appears to be a mere matter of chance, and not a 

 tendency to adopt the habit of the Fumeas. 



Habits of larva. — In its habitat, on old walls and rocks, the larva 

 moves somewhat freely from place to place. It spins a great deal of 

 silk on which it walks, and, in confinement, this is especially notice- 

 able. A number of larva?, sent from Guernsey, covered the inside of a 

 box, in which they had travelled, with a layer of white silk. They 

 hang freely by a silk thread, if disturbed, and regain their lost position 

 by means of it ; they also frequently come out of the case and re-enter 

 it. When drawn from the case, the larva can make very little use of 

 the prolegs on abdominal segments 3-6, the young larva holding its 

 abdominal segments up in the air, the adult larva looping considerably 

 without attempting to use these prolegs in walking. De la Voye observed 

 the peculiar walking habit of the young larva, whilst Reaumur men- 

 tions that the larva has the power of leaving its case and hanging by 

 a silk thread, and Gregson remarks (Entom., vi., p. 409) that the 

 larvae of the Howth Inberniaila (probably this species) left their cases 

 at pleasure and roamed about freely, some with the abdomen raised, 

 others dragging the body along, but never using the abdominal feet ; 

 they often suspended themselves by a silken thread, and two or three 

 constructed new cases of lichens. Reaumur notes that when the larva 

 is nearly ready to pupate it fastens the anterior (wide) end of the case 

 to the surface chosen, generally on the wall on which it has lived, or 

 in the hollows thereof, and spins a thick silken web of the same size 

 as the opening of the case, so as to fill up the latter completely. 



Larva. — The larva is, when extended, about 3}mm, long (probably 

 not quite two-thirds grown), but when contracted not much more than 

 half that length, and 1mm. wide at the broadest segment (the 4th 

 abdominal). Its head is comparatively large, partly retractile within 

 the prothorax, the head is deep brown-black, glossy, with a few 



