1893.] Harvest-Spider and its Variations. 535 
These forms were next discussed in my paper on “The 
Harvest-spiders of North America,” in which P. ventricosum is 
definitely placed in Liobunum, and P. formosum together with 
a southern form not before described is referred to the new 
genus Forbesium. The new form is named F. hyemale. “The 
former (F. formosum) is a distinctly northern species, ranging 
from New York to Colorado, while the latter (F, hyemale) is 
evidently its southern representative. ” 
Finally in the American Naturatist for September, 1892, 
I announced that by keeping specimens of F. formosum taken 
in early spring in vivaria, I had determined that it was the 
immature form of L. ventricosum; and about the same time I 
published® extended descriptions of adults of both sexes of L. 
ventricosum. 
For the purposes of the present study I have had a consider- 
erable number of adult specimens from nine widely separated 
states, viz.; Maine, New Hampshire, New York, Ohio, Michi- 
igan, Illinois, Nebraska, North Carolina and Mississippi. 
Besides the adults I have had an immense number of the 
immature form (formosum) and a few of the form at present 
called F. hyemale. 
The first glance at the adult specimens shows that there is a 
great variation in the size of the body and length of legs in 
different localities. The Mississippi forms are twice as large 
as those from New Hampshire; while those from the states 
between present intermediate sizes. This is shown by the 
measurements in millimeters in the following table; numbers 
1 to 6 are males, and 7 to 12 females. 
To show graphically the gradual lengthening of the legs of 
_ this harvest-spider as it goes southward I have reduced the 
length of the second pair, as given in this table, to the 
straight lines reproduced on the opposite page. The Miss- 
issippi specimens were taken at the Agricultural College in the 
central part of thestate. I regret that I have not more speci- 
mens from the region between Ohio and Mississippi to show 
the transition more completely. 
*Am. Nat., Oct., 1890. 
*Trans, Am. Ent., Soc., XIX, 188. 
