PSYCHIDAE. 369 



the newly-hatched larva? at the bottom of the case (which are hatched 

 from the eggs first laid), manage to escape at all. The way in which 

 the eggs are packed is suggested in pi. v., fig. Se. 



The young larva? as soon as hatched (pi. v., figs. 4a-/) make 

 themselves cases, usually robbing the maternal case for the purpose, 

 forming first a small oval collar which is gradually increased in length 

 (figs. 4a-/) until the case is completed. The young larvae appear 

 to be very generally more or less polyphagous, feeding on low plants, 

 grasses, and more rarely upon the leaves of shrubs and bushes. The 

 excrement is got rid of through the posterior end of the case. The larval 

 cases are covered with rock or plant debris. As the larva? increase in 

 size, coarser material is used, with which to clothe their cases, and, 

 although there is considerable variation in the materials used, there is 

 a very general similarity in the cases of the same species, and, in 

 nature, each species uses somewhat similar materials if available, or, 

 if different materials be used, they are attached similarly. The case 

 is spun down at each moult and at pupation, and the number of moults 

 varies with the species, rarely, however, exceeding five. The larva? are 

 usually most active in the hot sunshine, because they chiefly feed by day, 

 although Standfuss notes Stenophanes yraslinella, Sterrhopterix stand- 

 fussi, and probably Pachythelia villosella, as feeding almost exclusively 

 by night. Some species feed up rapidly and undergo their transforma- 

 tions in one year, others feed up more slowly and hybernate the first 

 winter as a small, and the second as an almost full-grown, larva, and 

 thus take two years to complete their metamorphosis, whilst almost 

 all the species pupate in the spring or early summer. Hofmann notes 

 that Ptilocephala atra (angustella) and Pachythelia villosella are among 

 those that are scarcely half grown during the first winter and hybernate a 

 second winter fully grown, appearing as imagines the following summer. 

 Hartmann observes that, in his experience, C. unicolor, P. villosella 

 and Stenophanes yraslinella, hibernate twice as larva?, and Standfuss 

 also allows 8. graslinella, Sterrhopterix standfussi, C. unicolor, Psyche 

 viciella and P. villosella two years before becoming full-fed. We have 

 already noted that many of the larva? are general feeders, although 

 some few appear to be restricted to special food-plants— grass, plantain, 

 lettuce, willow, &c, are given by various authors as being generally 

 acceptable. The peculiar manner in which the larva? walk, the third 

 pair of legs being moved forwards together as if they were the prongs 

 of a fork, has repeatedly been noticed. 



Until the newly-hatched larva has constructed its case it is very 

 restless and refuses to eat. Under artificial conditions the larva? will 

 sometimes utilise unusual materials for this purpose, fragments of paper, 

 cork, &c, but in nature many species are somewhat particular as to 

 the materials used, and the cases of such species as Amicta quadrangularis 

 and Chalia hochinyii are as remarkable for the accuracy of their con- 

 struction and the regularity of the pieces bitten off with which 

 to form the case, as are the snailshell-like cases of Apterona, the 

 species of Avhich construct, with silk and earth and vegetable debris, 

 cases that are exactly like the shell of a snail. Although the 

 female cases are usually much larger than those of the male, the 

 latter frequently uses coarser material, and Hofmann specially notes 

 the male case of Oreopsyche muscella as being of smaller size and 

 more slender form than the female case. We have already observed 



