74 
dish, almost colorless. Body broadest at shoulders, tapering behind; 
bristles long and fine, in the usual arrangement, subfrontal pair not 
twice as long as frontal pair. Thumb of palpus rather long; on its tip is 
a cylindrical finger; on its upper corner is a hair, and on the upper side 
toward base is a small finger; in male above on inner tip of tibia of pal- 
pus is aspine or spur. Mandibular plate about twice as long as broad, 
tapering forward, broadly rounded at tip, with a small although 
distinct notch in the middle. Legs of moderate length, 
femur I fully twice as long as broad, tibia a trifle longer 
than patella, tarsus rather slender, terminating in a 
claw which is suddenly and strongly bent near the mid- 
dle and four-cleft beyond. 
It is quite probable that this species is the one called 
by Boisduval (Entom. Horticole, p. 84) Zetranychus 
Fic. 10.— Tetrany. Cucumeris, but the descriptions of that author in this 
chus bimaculatus: genus are useless for identification. Quite possibly 
palpus—enlarged marie : 5 : r 4 
(original): several of his names apply to this species. The forms 
found in the greenhouse do not appear to differ from 
those on garden vegetables and horticultural plants. It appears to be 
abundant all through the Eastern States and in several localities in the 
West. Specimens have been studied from Orono, Me., on various 
greenhouse plants; from Washington, D. C., on violets in greenhouse, 
on peach (curling the leaves), on Datura, on squash, on corn, and on 
strawberry; from Punta Gorda and Key Largo, Fla., on eggplant; on 
watermelon from Eustis, Fla.; on beans at Auburn, Ala.; and on roses 
from Weiser, Idaho. Professor Harvey records it from greenhouses 
in Ithaca, N. Y., New York City, and Westgrove, Pa. 
The color and size are extremely variable. Yet ina 
lot from one plant and one region the adults are usually 
of one coloration and one size. Other lots from other 
localities have a much different appearance, but when 
mounted and examined do not disclose any structural 
difference. The specimens from Florida and those on 
Datura and violets from Washington, D. C., are red; Hel cass 
those from Orono, Me., on squash and peaches from — chus bdimacula- 
the District of Columbia, and on rose from Idaho are ene eee 
greenish, more or less marked with dark. The speci- nai). 
mens from squash and Datura had made a considerable 
amount of web, much more than those on greenhouse plants. 
This species has, more than any other, stood for the ‘‘red spider,” 
Tetranychus telarius. Harvey remarks that specimens sent to him as 
the genuine *‘red spider” did not differ structurally from his species. 
