PSYCHIDES. 105 



According to Heylaerts the normal length of life for most Psychids 

 is two years, although a few species of Psyche and Fumea complete 

 their metamorphosis in a single season. Our own experience tends to 

 show that most of the British species appear to take only one year. 

 After each moult, the form of the case and the markings of the larva 

 are more pronounced, there being considerable difference betAveen the 

 case of the newly-hatched larva and that of the adult, as also in some 

 small details of colour and shape between the larva? themselves. The 

 number of moults is stated to be five or six. 



The adult larva is somewhat short, but very powerful. Its head is 

 large ; the female larva has, according to Heylaerts, a rather larger 

 head than the male ; the mandibles are strong, the antennae short, the 

 palpi quite ordinary. The ocelli are arranged in semicircular form on 

 either cheek, whilst the long tubercular hairs are conspicuous. The 

 thoracic segments carry shiny, dorsal, corneous shields, which are 

 generally marked with longitudinal striaa, the medio-dorsal almost 

 always the most strongly marked, whilst the metathoracic shields are 

 usually weaker than those of the pro- and mesothorax. The arrange- 

 ment of the tubercles on the abdominal segments is one of the most 

 important characters presented by the adult Psychic! larva. In the lower 

 subfamilies, i is nearer to the median line than ii, forming, in fact, quite 

 typical trapezoidal tubercles. As we ascend to the more specialised 

 families, ii is gradually brought into line (behind) with i (Taleporia), 

 whilst in the higher families it becomes nearer to the median line than 

 i, and at last moves forward, so as to be within, and almost in the same 

 straight line transversely with, i. Tubercle iii is supraspiracular and 

 strongly marked, iv and v close together below the spiracle, iv with a 

 strong, v with a weak, seta, vi is below the subspiracular and vii occurs 

 as a marginal tubercle at the base of the prolegs. All except vii are 

 simple and bear a single hair or seta. The anal flap is usually corneous, 

 often dark and shiny. The true legs are short and powerful, the third 

 pair specially well developed, the prolegs are very short but compara- 

 tively strong, carrying, also, an almost complete oval of crochets, 

 the anal pair being still more powerful and enabling the larva to cling to 

 the inside of the case. Dyar states (( 'lass, of Lepidopterom Larvae, 

 pp. 198-199) that " the three tubercles above the spiracle are retained 

 on the middle segment ; the substigmatal tubercles are approximated ; 

 the anterior one of the four on the base of the leg seems to have been 

 moved up forming tubercle vi, which is thus anterior." He further 

 states that " the primitive form of tubercle (consisting of a little 

 chitinous button on the skin bearing a single long hair), present in the 

 less specialised families of all the groups, is found exclusively in the 

 Jugatae (Hepialids and Micropterygids) and Psychidae." On larval 

 characters, Dyar makes (Ibid., pp. 201-205) the Psychidae equal in rank 

 to all the remaining Frenatae, although later (Additional Notes on 

 ('lass, of Lep. Larvae, p. 58) he retracts, and says that " although the 

 larva? of the Pxychidae differ markedly from those of the other families 

 in the reversed alternation of tubercles i and ii (ii being retained on the 

 same subsegment as i and not on a posterior one), the family cannot 

 be given superfamily rank on this character." Pacot considers with 

 us that it is an important feature of the Psychid larva that i is more 

 remote from the medio-dorsal line than ii. It is clear that Dyar is 

 referring, in the above quotation, to the higher Psychids only, in which 



