174 
Psyche 
[June-September 
A set of 10 specimens of each sex was measured to give some idea 
of the range of variability within a species. A series of 19 different 
measurements was made of selected specimens of all species. Since 
eastern and western populations of Trochosa terricola differ in the 
number of posterior cheliceral teeth (Map 1) and in color and were 
described as different species, it seemed best to treat them separately 
for comparison. Six additional measurements of T. terricola epi- 
gyna, used by Locket and Millidge (1951) to separate female speci¬ 
mens of European Trochosa , were also made to compare North 
American populations of terricola with European populations. The 
range and mean for the more significant measurements are recorded 
for each species. The measurements should prove useful not only to 
identify certain species of North American Trochosa, but to help 
distinguish this genus from others as the study progresses. Prelimi¬ 
nary measurements of other lycosids indicate that both the eye 
arrangement and ratio of leg length to carapace width or length are 
useful in distinguishing genera. 
Diagnosis. The species under investigation is compared to its 
closest relative(s) and differences that distinguish them are noted. 
Natural History. In discussing methods (in a broad sense) it is 
appropriate to emphasize the importance of routine observations in 
the field. It is not the province of the systematist to explore and 
record detailed elements of the ecology and behavior of each species 
he studies, nor is it practicable from the standpoint of time, but it 
behoves him to note the habitat where certain species are found and 
any peculiar behavioral traits associated with the species. This kind 
of information is often as valuable to the systematist as that con¬ 
cerning morphological features and should be incorporated into 
decisions about species relationships. 
Distribution. The geographic range of the species is given. 
Records. Includes only those specimens examined. Collecting 
localities for Canada are listed by city or town and separated by a 
semicolon. Multiple records for the United States are listed by 
county and separated by a semicolon. Collection records at the 
periphery of the species range are given in detail. The lower case “o” 
represents immature specimens. 
Acknowledgments 
This study was made possible by the loan of large numbers of 
specimens from the Museum of Comparative Zoology, Cambridge, 
