1893.] Harvest-Spider and its Variations. 539 
adult L. ventricosum appear. This is precisely the condition in 
the northern states. An idea of the similarity of the two 
immature forms in structural details may be obtained by com- 
paring Fig. 1 with Plate XIV, Fig. 2. 
The southern form of L. ventricosum should evidently be 
considered a geographical race sufficiently distinct for sub- 
specific name. Inasmuch as hyemale has already been applied 
to the stage immediately preceding the adult it may well be 
used for this race, and the form be known as Liobunum ventri- 
cosum hyemale. Just where the line dividing the two forms 
should be drawn is difficult to say without more material, but 
it probably occurs near the latitude of southern Ohio. 
LAws oF VARIATION IN HARVKST-SPIDERS. 
Comparatively little definite investigation of the geographi- 
cal variation of North American invertebrates has yet been 
undertaken. In the vertebrates—especially birds and mam- 
mals—much attention to the subject has been given by Baird, 
Allen and other well-known zoologists, so that a number of 
general laws have been formulated To determine to what 
extent these laws hold true for the invertebrates, as repre- 
sented by the Phalangiide, I have ventured to formulate some 
of the results obtained in my studies of this group—results 
which in part have already appeared in the Narura.ist and 
in part are yet unpublished. At'the present stage of investi- 
gation such formule cannot be considered as final by any 
means, but if they serve no other purpose they will be useful 
in determining the direction of future work. 
(1.) In mature individuals of the same species and sex from 
a given locality there may be found a decided variation in 
size of body and length of legs. In a series of fifty or a hun- 
dred such individuals taken at random the body of the 
largest specimen will usually be from one-fifth to one-fourth 
longer than that of the smallest; and the legs of the longest- 
legged individual are likely to be from one-fifth to one-third 
longer than those of the shortest-legged specimen. 
See the AMERICAN NATURALIST, Vol. XXVI, pp. 87-89. 
