No. 2303. RED SPIDERS OF AMERICA— McGREQOR. 645 



each side of abdomen. Body of female rhombic-ovate, widest across 

 cephalo thorax, exceedingly obese for the size of the legs; cephalo- 

 thorax rounded generally anteriorly with a slight concave border 

 overlying the palpi; male almost sagitate in outline, conspicuously 

 reduced in proportion to the legs. Mandibular plate about half 

 again as long as wide, tapering somewhat anteriorly, with a distinct 

 emargination and with a superimposed chitinized ridge anteriorly. 

 "Thumb" of palpus subcorneal, upper surface twice transversely 

 depressed with an intervening dilation, bearing at its tip a long 

 slender "finger," which is over four times as long as thick; on its 

 upper side arising between middle and tip are two stout hairs, and 

 near the base of upper side arise a reduced "finger" and two stout 

 hairs; the claw of the penultimate joint reaches only to the basal 

 "finger"; a hair arises ventrally from the "thumb" and another 

 laterally from the penultimate joint. Legs of female are of average 

 length, barely equaling length of body; those of male are about twice 

 as long as body ; femur between four and five times as long as thick, 

 three-quarters again as long as tarsus; tibia somewhat longer than 

 patella, which is over twice as long as trochanter; relative length 

 of joints as follows: Coxa, 9; trochanter, 3.75; femur, 14; patella, 

 8.75; tibia, 10.9; tarsus, 8; tip of tarsus not provided with a claw, 

 it being reduced to a vestigial protuberance; the customary series 

 of four tenent hairs arise from the onychium. 



Type.—Cat. No. 19089, U.S.N.M. 



The type material was from Orlando, Florida, August 16, 1913, 

 from the under surface of castor beans (Ricinus comraunis) and velvet 

 bean leaves. Mr. W. W. Yothers wiites that the species is an im- 

 portant pest of the castor bean plant in Florida, but that at times 

 it is controlled by a predaceous mite (Sciulus, species) and by the 

 coccinellid Stethorus, species. Larvae and pupae of Arthrocnodax 

 Carolina have been observed on infested castor bean leaves from 

 Orlando, Florida. 



ANYCHUS RUSTI (McGregor). 



Tetranychus rusti McGregor, 1917, Proc. U. S. Nat. Mus., vol. 51, p. 582. 



Color ranging from yellowish or gi-eenish to red. Eyes (in mounted 

 material) translucent, directly over coxae II and between subfrontal 

 and posterior cephalothoracic bristles. The dorsal epidermal ap- 

 pendages are not distributed to conform with the usual arrangement 

 for this genus, but a series of 26 moderately short, nontapering, 

 sparsely serrate, rod-like appendages are distributed on the dorsal 

 aspect of the bodj^ as follows : One at either side of mandibular plate 

 anteriorly, one just anterior to each e3^e, one just posterior to each eye, 

 six forming a fringe at hind margin of body, three along each side 

 of abdomen, one on either side of median axis in line with coxae III, 



