48 
Psyche 
[March 
field studies, accumulated data on the spatial distribution of these 
skippers in Texas and have paid special attention to the critical zone 
of junction. As happens for so many east-west species pairs, central 
Texas is where the action is (see Remington 1968 for a recent sum- 
mary and general discussion). We find the two species sympatric 
and synchronic at several points ( fig. 5 ) — and find no evidence what- 
soever of hybridization between them (either with or without intro- 
gression ) . 
P. oileus is apparently common and resident in coastal regions of 
Texas and sporadic at interior localities in east and eastcentral Texas. 
All peripheral interior records derive from only one to a few speci- 
mens caught late in the year: Dallas, 1 c? , IX-17-1948 (H. A. Free- 
man) ; icf, X-16-1949 (H. A. Freeman); New Braunfels, 3 cf , 
X-8-1967 (J. F. Doyle III, R. Jameson, M. A. Rickard) ; San 
Antonio, icf, X-20-1945 (H. A. Freeman). This, along with the 
lateness of the lone Arkansas record (1$, IX-10-1929, H. A. Free- 
man), suggests a fluctuating northern and western distributional 
limit that expands substantially in favorable years. The dots repre- 
senting P. oileus in Chambers, Liberty, and Victoria counties (fig. 5) 
are based on larval collections reported by Bottimer (1926: 797) 
but are the only records (of either species) appearing in fig. 5 that 
are not taken from adult specimens examined by one or both of us. 
Although Freeman (1951: 21) reported P. philetas only from far 
western (Marathon) and far southern (Laredo, Pharr) Texas, we 
find it resident through much of the central part of the state; and 
we believe that our present picture (fig. 5) is still incomplete. At 
middle latitudes in central Texas, the eastern distributional limit is 
roughly the eastern edge of the Edwards Plateau (marked by the 
Balcones Escarpment). Even there, however, in the vicinity of Aus- 
tin, New Braunfels, and San Antonio, P. philetas is not rare; and 
correspondence is inexact, as evidenced by the occurrence of P. philetas 
early in the year in fresh condition in Gonzales County, 29 miles 
southeast of the Balcones Escarpment. Between Austin and San An- 
tonio, the escarpment shifts rapidly from a north-south to an east- 
west orientation and extends westward from San Antonio. In 
southcentral Texas, then, P. philetas departs widely from the Ed- 
wards Plateau, ranging east to Corpus Christi and south to the Rio 
Grande. Altogether, its eastern limit is a fairly straight line falling 
between the 97th and 98th meridians. 
Every instance of sympatry of P. oileus and P. philetas is in central 
and especially southcentral Texas between the 97th and 100th merid- 
ians. In this narrow zone we have found these species sympatric — 
