1893.] Harvest-Spider and its Variations. 541 
(4.) In the plains region of the Northwest (Dakota, Nebraska) 
the legs are considerably shorter than in similar latitudes in 
New England. 
For example, the second legs of a male Liobunum longipes 
from Brookings, South Dakota, measure 62 mm., while those 
of a Hanover, New Hampshire specimen measure 74 mm. 
The case of the Striped Harvest-spider (L. vittatum dorsatum) 
is still more striking; the second legs of a New Hampshire 
specimen measure 71 mm., while the normal length in South 
Dakota seems to be only 35 mm. 
In addition to ‘the above the following laws of vertebrate 
variation appear to hold good in the Phalangiide. 
(5.) “ The maximum physical development of the individual 
is attained where the conditions of environment are most 
favorable to the life of the species. 
(6.) “The most typical or most generalized representatives 
of a group are found near its center of distribution, outlying 
forms being generally more or less aberrant or specialized. ” 
Explanation of Plates. 
Plate XIII. Fig. 1—Liobunum ventricosum (Wood), male. 
Natural size. 
“ 2—Parts of same. Magnified. 
“ 2a—Body. 
“ 2b.—Eye eminence. Side view. 
“ 2¢¿—Eye eminence. Front view. 
“ 29d.—Palpus. Side view. 
“ 2e—Claw of palpus. Side view. 
“ 9f--Maxillary lobe of second pair of legs. 
Plate XIV. Fig. 1—L. ventricosum hyemale. Immature. 
- Natural size. 
“« 2—Parts of same. Magnified. 
“ 2a—Body. 
“ 2b—Eye eminence. Side view. 
“ 9¢—Eye eminence. Front view. 
“ 9d—Palpus. Side view. 
“ 2e—Claw of palpus. Side view. 
