062 I'ROCJ^JUJDINGS OF THE NATIONAL MUSEUM. vol. 5«. 



claw divisions, the two inner of which are somewhat stronger than 

 the others. The usual series of four teiient hairs arise by the sides 

 of the claw base. Collar trachea of novel type; runs baclcvvard and 

 doAvn-ward as a straight, even-calibered tube, and then bends sharply 

 upward into a short, wide chamber, the two arms making an angle 

 with one another of less than 90°. The penis shaft (pi. 12, fig. 2) 

 appears to taper gradually to a strong, unbarbed hook. 



Type.— C&t. No. 20166, U.S.N.M. 



From Portland, Oregon, on wild cherry (Prunus, species). Prob- 

 ably nearest T. monticolu^s, from which it is readily separated through 

 the collar trachea and penis characters. 



TETHANYCHUS MONTICOLUS McGregor. 



Plate 79, fig. 3. 



Tetranychus moniicolus McGre(50u, 1917, Proc. U. S. Nat. Mus., vol. 51, no. 

 2167, p. 584. 

 Body of a rather uniform pale amber color. Eyes pale ; one cornea 

 on each side close behind the subfrontal bristle, behind which are the 

 carrot-colored eyespots. Legs and palpi rather paler than body. 

 Dorsal l^ristles colorless, distinctly plumose, 26 hi four rows, the 

 longest about five-ninths the width of body. Body pyriform- 

 elliptic, usually widest between legs II and III. Mandibular plate 

 nearly three times as long as broad, narrowed considerably ante- 

 riorly to a well-rounded, unemarginated tip. "'Thumb" of palpus 

 two-thirds as long as broad, bearing on its truncate tip a subconical 

 ''finger,'' whose base is only two-fifths as wide as the tip of the 

 "thumb." On its upper distal corner are two pin-shaped pseudo- 

 fingers, in length somewliat exceeding the terminal ''finger," on 

 upper side, about a third the distance to base, is a small ''finger;" 

 and immediately proximad to this is a short hair. Another similar 

 hair occurs on the upper side just at base ; a hair arises on the ventral 

 aspect of the "thumb." The claw of the penultimate joint does not 

 reach quite to the dorsal "finger." The legs are short, not much 

 over two-thirds the length of body (exclusive of palpi). Femiu- a 

 little more than twice as long as wide, not quite as long as tarsus; 

 tibia a little longer than patella, which is five-sevenths again as long 

 as the trochanter. Relative lengths of joints are as follows: Coxa, 8; 

 trochanter, 7; femur, 20; patella, 12; tibia, 14; tarsus, 22. Tip of 

 tarsus bears a claw which is bent near its middle and cleft into six 

 slightly curved spurs. Tlie customary four tenent hairs arise, two 

 on either side by base of claw, tarsal claw of male differing from that 

 of female in that its six divisions are much shorter and more al)ruptly 

 acuminate. Tlie collar trachea is rather novel; it runs downward 



