106 EVOLUTION OF COLOR PATTERN IN LITHOCOLLETIS. 
П. METHODS AND OBSERVATIONS. 
(a) SYSTEMATIC POSITION AND CHARACTERISTICS OF LITHOCOLLETIS. 
The genus Lithocolletis belongs to the large family Tineid: of the Micro- 
lepidoptera. It comprises a large number of very small moths, varying in 
expanse from 4 to 12 millimeters. The larve are exclusively miners, usually in 
leaves or very rarely in the bark of stems. The entire larval and pupal existence 
with one or two exceptions is passed within the mine. The genus, as originally 
established, has a remarkably uniform structure and a very characteristic 
appearance, enabling one to recognize the species easily. The structural char- 
acteristics which distinguish the typical and principal group are the following: 
P gi. Face smooth; erown tufted; labial palpi por- 
uec RU Сыннын rected or drooping, moderately long and pointed; 
=== maxillary palpi rudimentary; tongue of moderate 
К length; antenne nearly attaining the wing length, 
Ена simple in the male, basal joint thickened and bearing 
buo Wound dk Leas Ж poete The forewings are elongate, lanceolate, 
acuminate. The hindwings are about one-halfthe 
breadth of the forewings, linear lanceolate and fringed with cilia whose length 
is from four to five times the breadth of the wings. The venation is illustrated 
by Fig. 1;' forewings, 1b simple, 3 absent, 4 absent, 6 absent, 7 to costa, 8 ab- 
sent, 11 absent; hindwings, 3 absent, 4 absent, transverse vein absent between 2 
and 5, 6 absent. The posterior tibie bear appressed hairs. 
All of the European species and the great majority of the American species 
conform to the above conception of the genus. There are, however, in North 
America a few species belonging to two different groups, which differ structurally 
from the typical species; for these, two subgenera, Porphyrosela 
and Cremastobombycia have been erected (Braun, '08). The === 
former of these, Porphyrosela, differs from Lithocolletis in the “>> 
absence of vein 10 of the forewings, the absence of a pecten on Ss 
the first joint of the antennz and in the absence of hairs on the 
hind tibiz.? It thus represents a later development, phylogen- 
etically, in the direction usually taken in this family; that is, 
a reduction in the number of veins (Fig. 2). Cremastobombycia is of a more 
ancestral type than the typical Lithocolletis; it possesses an additional vein in 
each wing; on the forewing, vein 4 is present and stalked with 5; on the hind- 
wing, vein 6 is present and long stalked with 5 (Fig. 3). 
In the European fauna, the typical Lithocolletids are a very homogeneous 
group of species both as regards larval characteristics and imaginal markings. 
1 
1€. jb 
Fic, 2. Venation 
of Porphyrosela. 
1 References in italics are to the text figures, those in Roman type to the figures on the 
plates. 
? Since this paper was written, studies on very closely allied species have shown that these 
characters are not sufficiently constant to define a genus (Meyrick, Genera Insectorum, 128me 
Fascicule, p. 5, 1912). Vein 10 is probably faintly visible in large specimens of L. desmodiella. 
