92 
Psyche 
[September 
acceptable accuracy. The numbers in parentheses are the 
totals of the records involved. 
Latitude 
Elevational Range 
N. cockerelli 
Elevational Range 
N. albisetosus 
36°-34° 
(3) 3000-3300' 
no records 
34°-32° 
(16) 1000-4500' 
(8) 1800-5200' 
32°-30° 
(20) 1300-5000' 
(22) 3100-5800' 
30°-28° 
(10) 700-5100' 
(7) 2600-5900' 
28°-26° 
(5) 4300-5800' 
(5) 5500-5700' 
26°-24° 
(5) 4000-6100' 
no records 
24°-22° 
(5) 6100-7000' 
no records 
The following points in the above table should be noted : 
1. The range of cockerelli extends further north and 
much further south than does that of albisetosus. There 
are no records for the latter species north of Latitude 34° 
or south of Latitude 26°. 
2. The effect of latitude on the upper limit of the eleva- 
tional range is different in the two species. From Latitude 
34° to Latitude 26°, where they occur together, the rise 
in the upper elevational limit is 700 feet for albisetosus 
against 1300 feet for cockerelli. Over the entire range of 
cockerelli the rise is almost 4000 feet. 
3. In the northern part of the common range the upper 
elevational limit of cockerelli is approximately 1000 feet 
below that of albisetosus. But because this limit rises 
more rapidly in the case of cockerelli, the two species have 
the same upper limit about Latitude 26°. South of that 
latitude the upper limit of the vertical range of cockerelli 
continues to rise, but, since albisetosus does not occur south 
of Latitude 26°, the records for cockerelli from stations 
above 6000 feet cannot properly be compared with those 
for albisetosus. 
4. In the common range there is a considerable area 
of overlap in the vertical ranges of the two species. The 
two vertical ranges are never identical, however, for al- 
though the upper limits may coincide, the lower limit of 
cockerelli always descends below that of albisetosus. This 
difference is at least 800 feet and often much more. 
