302 OBERHOLSER, Description of a New Empidonax. fale 
whole series, together with others which are apparently intermedi- 
ates. Whether or not this occurrence of paler birds in the south- 
western United States shows an inclination of dfficilis toward 
intergradation with céveritius is not possible certainly to determine 
from the material at present available, but the greater frequency of 
such examples in southern California seems at least to indicate 
that such may be the case. One bird from the Santa Catalina 
Mts., Pinal County, Arizona (U.S. N. M. No. 117235), is very pale 
throughout, and differs from cémeritius chiefly in the quite continu- 
ously yellow under parts. A specimen from Napa Valley, Cali- 
fornia (U. S. N. M. No. 12880), is very similar to the preceding, 
but is browner and slightly darker above, less extensively yellow 
below, and rather darker across the breast. Whether or notthese 
two specimens are to be called cineritius seems somewhat doubtful. 
I very much hesitate to record them as such, though they cer- 
tainly do not represent diffcilis, unless they may be considered 
abnormally faded summer birds. 
The young of Lmpidonax difficilis appears to be, as a rule, very 
brown above and light yellowish or buffy below (not dull white as 
mentioned by Mr. Ridgway’), although two immature specimens 
from Sitka, Alaska, are as bright olive above and as deep yellow 
below as almost any of the adult examples. 
MEASUREMENTS OF SPECIMENS OF Emfidonax insulicola. 
os Sale 4 
SOU 4/8. = 
S| et : So |) a oe 
+5 Locality. Date. so aa As 
An i 4 io 7 9 oO oO 
26 a eh) 6 | 24 A | sl 
Wo pa a c= a Ee} g cs) 
. & oO iS co od oO a 4 
jaye) wn S i a sa = 
140076 |¢ ad. | Santa Catalina I., Calif. | Apr. 15, 1892. | 69.5 | 61 II 9 18 12 
140077 |d' ad. | Santa Rosa I., Calif. July 3, 1892. | 64.5 | 60 13 9 18 12.5 
140078 | ad. a ee s € rs 68 59-5 | 12 9 17 13 
140079 |g ad. | Santa Cruz I., Calif. July 13, 1892.| 69.5 | 62.5 | 12 8.5 | 18 12.5 
140080 |g ad. oe ss July 16, 1892. | 69.5 | 64 II 825) | 17.5) xs 
Average 68.2 | 61.4 | 11.8 8.8 | 17.7 | 12-6 
1 Manual of North American Birds, 1887, 340. 
