108 BRITISH LEPIDOPTERA. 



Some cases are smooth, hardened maybe by the powdered dust with 

 which they are often covered, others are quite soft, even when solid in 

 appearance. The cases of the Taleporiids and their nearest allies form 

 a more or less triangular-based prism, drawn in towards the end, those 

 of the Luffiids form a cone, those of the Fumeids and higher Psychids 

 make usually a cylindrical tube of silk to which straws, &c, are 

 attached, whilst the Apteronids have a case that is quite heliciform, 

 and closely resembles a snail's shell. The case made by the male 

 Psychid larva is usually smaller than that made by the female ; 

 this is markedly so in many of the Fumeids, Epichnopterygids, &c. 

 One end of the case is usually kept open, and through this the larva 

 thrusts its head and thoracic segments when walking or feeding. At 

 the least danger it withdraws itself and closes its home by tight- 

 ening certain silk filaments attached to the edge of the entrance, 

 the other ends being fastened to the inner walls of the case ; 

 these normally hang loosely, but when tightened, the open end, 

 being of a soft texture, is drawn into the case and the mouth is 

 closed perfectly. At the other end of the case, in the Psychinae, 

 is a longer or shorter silken tube, extending somewhat beyond 

 the covered portion. This tube is often lengthened quite abnor- 

 mally when the larva is ready for pupation, the work taking some 

 hours, and its formation is a sure sign that the larva is full-fed. 

 When this is made, the larva spins down the previously open end of 

 its case to a rock, stem, twig, or trunk of a tree, turns itself round so 

 that its head is towards the unfixed end, and awaits pupation. Stand- 

 fuss states that after the larvae of the higher Psychids have fixed 

 their cases, and before turning round in them, they change their skin, 

 doing so in the ordinary way, so as to push the debris out of the free end. 

 After this moult these larvae are said to be much changed ; the new 

 skin is very delicate, the markings have disappeared, the true legs are 

 weaker and the body stouter and shorter, so that it is scarcely recog- 

 nisable. In this condition, the larva turns itself round, and, without 

 eating, remains yet another fifteen to twenty days before pupation. 

 After it has pupated this last delicate larval skin is found inside at the 

 fixed end of the case. One suspects that the whole of this statement 

 can be true for only a very small number of species. Zeller had sup- 

 posed, in 1847, that the male larva had a moult more than the female, 

 as he observed the cast skin outside the cases that produced males of 

 Htenophanes {Psyche) apiformis and the delicate larval skin in the case. 

 Turati observed it in Meyalophanes (Psyche) turatii, and Standfuss in 

 Stenophanes (Psyche) yraslinella, whilst Heylaerts has observed it in ,S'. 

 f/raslinella, Pachythelia villosella, Sterrhopterix hirsutella, and Amicta 

 eckstemi, in which species the penultimate larval skin has been found 

 outside the cases from which imagines have afterwards appeared. He 

 states, however, most positively, that it happens in both sexes, and that 

 the peculiarity is not confined to those species whose male larvas make 

 a very long silken "cap" to their cases. Heylaerts further observes 

 that in some species the sexes take up a different position for pupation ; 

 in these, he asserts, the males frequently fix their cases near the 

 ground, the females (of the same species) ascending much higher for 

 this purpose. The same observer also makes the remarkable state- 

 ment ; "Pour nettoyer sa demeure, la chenille en ouvre la partie 

 posterieure et, avec ses mandibules, elle eloigne par la ses excrements. 



