1971] 
Powell & Burns — - Palearctic Moths 
39 
Fig. 1. Croesia forskaleana, male, dorsal view. New Market, Middle- 
sex County, New Jersey, VI-17-1968. 
Fig. 2. Croesia forskaleana, female, dorsal view. Palearctic. 
Fig. 3. Clepsis unifasciana, male, dorsal view. Palearctic. 
Fig. 4. Clepsis unifasciana, female, dorsal view. Palearctic. 
some rather recently introduced species have been so overlooked or 
ignored that only a vague rendering of their Nearctic history is 
possible. Three parallel cases involve Palearctic moths, the tortricids 
Acleris variegana ( Schiffermiiller) and Batodes angustiorana 
(Haworth) (Powell 1964#) and the oecophorid Borkhausenia 
(Batia) lunaris (Haworth) (Powell 1964c) : each inhabits parts 
of the Pacific Northwest and central coastal California without 
revealing whether it entered North America once and in the north, 
or once but to the south, or twice. 
Often there are several records of an alien species from about the 
time it was first noticed and a relative or absolute dearth of them for 
a long period thereafter. Even in so well sampled a group as butter- 
flies, the Palearctic hesperiid Thymelicus lineola (Ochsenheimer) 
— > which can quickly attain enormous population densities in newly 
colonized areas — was discovered at one locality in North America 
in 1910 and observed there for five years but was rarely recorded 
from anywhere for the next thirty years or more, in which it must 
have spread far in all directions from its origin (Burns 1966). 
For the two tortricids treated here, records are also intermittent 
in time and space. But the gaps are comparatively short and may 
not seriously hinder efforts at reconstructing New World movements 
of these moths. 
