existence, but must be looked upon merely as a convenience. The 

 case forms while the larva is feeding a shelter from the inclemency 

 of the atmosphere, and a retreat or hiding-place from its enemies, 

 and when the larva is full fed it has no need to go to the trouble of 

 spinning a cocoon, for the case already built is admirably suited to 

 the purpose. The Coleophorid larva is quite free to quit or abandon 

 its case at any time should this act be necessary. The larva may be 

 taken from its case, examined, and replaced in its case without 

 suffering injury, provided always the operation be delicately per- 

 formed. In fact, an exchange of cases may be made, not only 

 between individuals but between species, and the larvae will walk off 

 in their strange cases apparently quite unconcerned. Of course, it 

 is a well-known fact that several species of this genus habitually make 

 entirely new cases, but only, however, at certain periods of their 

 existence. Nevertheless some of these species may be induced to 

 make a new case at a time when under ordinary conditions they 

 would not do so, and even a species like C. /ineo/ea, which increases 

 its case by the addition of "leaf fragments," as Meyrick aptly puts it, 

 will make an entirely new case if circumstances favour such a pro- 

 ceeding. The cases are therefore merely shelters for the larvae. 

 Flimsy as they are when newly made, they become very tough, 

 forming a most efficient protection. From their great variety and 

 from the skilful methods employed in building them, we may argue 

 that they must be of very ancient origin. 



Although the cases differ so greatly in appearance, the funda- 

 mental form is the same — that is to say, a hollow cylinder, open at 

 one extremity and more or less closed at the other. The principles 

 of construction appear to be of two kinds — one, the commoner, that 

 of joining together the margins of two more or less symmetrical 

 walls, so that a flat case is made like the scabbard of a sword, which 

 is afterwards formed into a hollow cylinder by pushing out the walls ; 

 the other by addition of parts on the same principle that beads are 

 threaded on a string. Sometimes both principles are employed, as 

 in the case of species like C. li/ieo/ea, where one flat case is added to 

 another. 



In all instances that have come under my notice the interior of 

 the perfect case is always lined with silk. The exterior of the case 

 usually harmonises with the larva's surroundings ; and in many 

 instances, such as the case of C. onosmel/a on the tip of a bugloss 

 leaf, or more especially the case of C. jimcicoklla on a sprig of ling, 

 the resemblance of the case to portions of the food-plant is so exact 

 that the case is practically indistinguishable. On the other hand, 

 the almost black pistol cases of species like C. ibipetineUa and C. 

 anatipennella are quite conspicuous, as they rest on the upper side of 

 a leaf. But these, especially when the newest portions are spun of 

 white silk, have a strong similitude to a bird's dropping. 



When the Coleophorid larva is very small, it makes a minute case, 

 but as the larva grows it has to enlarge its shelter. The enlargement 



I 



