No. 2394. NEW NEAR ARCTIC SPIDER MITES— EW IN G. 663 



with a very thin and indistinct cornea. Cephalothoracic plate very 

 large, and, as seen in egg-bearing females, about as long from base to 

 tips of inner tubercles as broad, and fully equal in length to one-half 

 the length of cephalo thorax; inner tubercles but slightly surpassing 

 the outer, separated from the latter by emarginations which extend 

 almost to the base of the plate, and bearing scales considerably smaller 

 than those of the outer tubercles. (There is much variation in the size 

 of these inner tubercles, and the tubercle on one side may be decidedly 

 larger than its fellow on the other side, also the emarginations may 

 entirely separate the outer tubercles from the inner.) Mandibular 

 plate about three-fifths as broad as long and broadest at the base, nar- 

 rowly rounded in front, and without frontal emargination except in 

 rare instances. Abdomen usually broadest somewhat back of the 

 shoulders and broadly rounded behind. Anterior legs distinctly 

 longer than the body and provided at their tips with the usual arma- 

 ture. The much shorter remaining pairs are also provided with the 

 usual tarsal appendages. Length of egg-bearing females, 0.81 mm.; 

 width, 0.53 mm. 



Type locality. — Ashland, Nebraska. 



Type slide.— Cat. No. 23767, U.S.N.M. 



Described from egg-bearing females on type slide. This species 

 differs from praetiosa and brevicornis in a number of details, the most 

 important difference being in the great size of the cephalothoracic 

 plate and in its shape. The specimens on the type slide were taken 

 on Dutchman's breeches (Bikukulla cucullana (Linnaeus)). 



Genus RAPHIGNATHUS Duges. 



In this genus the integument is reticulate. The individuals are 

 stout, with short legs and large tarsal claws. About a dozen species 

 are known, three of which have been described from this country. 



RAPHIGNATHUS VIRIDIS, new species. 



Plate 125, fig. 5. 



Preserved specimens green throughout; body circular in outline. 

 Cephalothorax slightly smaller than abdomen and separated from the 

 latter by an evenly curved groove. Palpi large, surpassing the beak 

 by one- third their length; palpal thumb small but with setae as long 

 as the palpal claw. Abdomen broader than long, with integument 

 reticulate, as it is on the cephalothorax, but not pitted in either case. 

 Dorsal setae straight, simple, and stout, longest on the posterior mar- 

 gin of abdomen, where they extend to the tips of the tarsi of posterior 

 legs. Legs stout; anterior pair considerably longer than the others 

 and extending beyond the tips of palpi by the full length of their tarsi; 

 posterior legs quite short, extending beyond the margin of the body 

 by the full length of their tarsi and one-half the length of the tibiae. 



