266 litiiocolletida;. 



upper cuticle, some beneath the under cuticle, but the larva of 

 no species is known to mine indifferently the upper or under side 

 of a leaf. Tlie larva, in the process of its mine, contorts the leaf 

 more or less, the leaf curving towards the side on which the larva 

 is at work ; the larva carpets the loosened skni with silk, and 

 purposely pulls it so tight as to cause the loosened skin to pucker, 

 whereby the opposite side of the leaf naturally curves. Mr. Boyd 

 has suggested that the natural shrinkage of the silk may, without 

 any extraneous assistance from the larva, cause the puckering of 

 the loosened skin. Many of the larvre have the third and fourth 

 segments considerably enlarged. The larva3 of some species form 

 cocoons of silk, sometimes of very fine texture ; others interweave 

 the grains of excrement into the cocoon ; a few do not construct 

 any cocoon. Most of the species are double-brooded, appearing 

 in the perfect state in May and August, and the larvce feeding in 

 July and October ; a few of the latter brood remain iri the larva 

 state throughout the winter, but in most of the species the pupa 

 state is assumed before the commencement of winter, and many a 

 withered brown leaf blown hither and thither, at the mercy of 

 every gust, contains throughout the winter a living pupa, to ap- 

 pear in the following spring as one of these splendid insects. 

 The genus may be tabulated as follows : — 



a. Anterior wings with a hook in the cilia. Species 1-3. 

 a a. Anterior wings with no hook in the ciUa. 



b. Anterior wings dark, with a white, whitish, or silvery basal streak. 

 c. The basal streak dark-margined on both sides. Species 4-9, 



19, 20. 

 c c. The basal streak dark-margined only towards the costa. Spe- 

 cies 10, 12, 17, 20. 

 c c c. The basal streak with no dark margin. Species 11, 13, 

 14-16, 18, 21-25. 

 b b. Anterior wings white, with dark streaks or fascitx). Species 27- 



30, 41. 

 b b b. Anterior wings dark, with no defined basal streak, but with 

 two or more pale fascitc. Species 31-40. 



1. Roboris, Zell. Isis, 1839, p. 217; Id. L. E. i. 174. pi. 1. f.4. 

 — Rob()7rlla, Sta. — RoborifoUeUa, Dup. Alls anticis nivcis, macula 

 parva dorsali aurco-brunnea basim versus, fascia Iota ohUqiia a basi 

 costa) fere ad medium dorsi, aureo-bnmnea, pone medium lineis quatuor 

 costic, una dorsi nigris introrsum fiiscescente-marginatis, piiiiclo rotunda 

 apice atro, camlulnm ciliarum emittenie. Exp. al. 4 lin. 



Head wlnte, with a few fuscous hairs. Eace and palpi white. An- 

 tenna; whitish, witli fuscous anuulations. Anterior wings white, with 

 a small golden-brown blotch on the inner margin near the base ; an 



