18(i WILLIAM T. M. FORBES 



The larva- are similar to those of the cylindrical larval group of Lithocolletis. 

 All of our species mine leaves of Composite, forming wrinkled, tentiform mines. 

 They pupate in an elongate, dense, white cocoon sometimes ornamented with longi- 

 tudinal ridges. This cocoon is suspended inside the mine by two slightly diverging, 

 silken threads at the posterior end, and by either one or two threads at the ante- 

 rior end. 



The markings of the fore wings consist of a more or less distinctly developed 

 bascil streak, four white costal streaks, and two or three dorsal streaks. There 

 may be one or two more or less distinctly angulated fasciae, formed by the con- 

 fluence of opposite streaks. 



Key to the species 



A. Basal streak distinct, reaching almost to, or beyond, the basal fourth. 



B. Basal streak narrow, pointed, unmargined'. 1. solidaynnt. 



BB. Basal streak dilated posteriorly 2. ambrosiella. 



AA. Basal streak minute or wanting; markings silvery. 3. ii/tiota. 



1. C. solidaginis Frey and Boll. Fore wings reddish ocherous; a narrow, whitish 

 basal streak below fold; costal, oblique streak at one-third, oblique costal and 

 dorsal streaks at one-half, usually meeting in middle of wing; two posterior 

 costal, and one posterior dorsal, streak, all margined outwardly with blackish 

 scales. 7-9 mm. Underside miner in leaves of golden rod, Solidago sp. 



Distributed over the entire United States. 



2. C. ambrosiella Chambers. Fore wings reddish orange; a short, posteriorly 

 dilated, white basal streak; an oblique costal streak at one-fourth, a more or 

 less angulated median fascia; two posterior, costal, and one posterior dorsal, streak, 

 all dark margined externally. 5.5-6.5 mm. Mine on underside of Ambrosia and 

 Actinomeris; not projecting conspicuously on upper surface. 



3. C. ignota Frey and Boll. Distinguished from the preceding by the silvery 

 luster of the markings and the very short, indistinct basal streak. 6.5-7.5 mm. 

 Tentiform mine on under surface of leaves of Actinomeris, Helianthus, and other 

 Compositae. Conspicuous as a tubercular swelling on upper side. 



9. LITHOCOLLETIS Hiibner 

 Annette F. Braun 



Face smooth, crown rough-tufted. Labial palpi porrected or drooping, moder- 

 ately long, pointed. Maxillary palpi rudimentary. Tongue moderate. Antenme 

 nearly attaining the wing length; simple in male; basal joint thickened; bearing 

 a pecten (except in desmodiella) . Fore wings (fig. 120) lanceolate; R t and R 4 

 absent, M, absent, M 2 and M 3 coincident; Cu single -branched; 2d A simple. Hind 

 wings about one-half as wide, linear lanceolate; Mj and M 2 coincident, M 3 absent; 

 Cu single -branched; discal vein absent between Cu and M J+2 - Posterior tibiae with 

 loosely appressed hairs. 



Our representatives fall naturally into two distinct and well defined groups, 

 identical, however, in the structural details of the imago. The first group, com- 

 prising those species having a cylindrical larva, agrees closely with the European 

 species in the early stages and in the type of markings of the imago. The second 

 group includes all those species having a flattened larva, and is characterized by 

 a definite type of wing marking. 



The following characters will separate the two groups: 



Larva cylindrical; white streaks and fascia? dark margined internally. . . .Group I. 

 Larva flattened; white streaks and fasciae dark-margined externally 



(p. 195) . .Group II. 



