652 PROCEEDINOS OF THE XATIOXAL MUSEUM. vol.56. 



TETRANYCHUS ALTHAEAE Von Hanstein. 



Plate 79, fig. 8. 



Tetranychus nlthaeae Von Hanstein, 1901, Zeitschr. wi^ss. Zool., vol. 70, pp. 5^108, 

 pi. 6. 



Von Hanstein (10) described this mite from material on liollyhock 

 in Germany. His original description of T. althaeae was altogether 

 too vague to be of much value taxonomically. We are therefore 

 including Tragardh's (18) revised diagnosis, which in substance is as 

 follows : 



Length of female, 0.570 mm.; of male, 0.430 mm. Body of 

 female broadly oval, more reduced backwards than forward, and 

 with a slight constriction between proterosoma and hysterosoma, 

 the greatest width, 0.225 mm., is not at the shoulders, but nearer 

 the middle. The legs are relatively longer in the male than with 

 the female. The body hairs are finely pilose, quite pointed and 

 short (about 0.09 mm.), not arising from elevations of the cuticule, 

 and consisting of 13 pairs in the typical arrangement; frontal hairs 

 only haK as long as subfrontal ones. Pedipalps in both sexes with 

 claw shorter than "thumb." Male palpus with claw small, shghtly 

 bent, and reaching very little onto the "thumb," which is sloping 

 conical so that the dorsal line is longer than ventral line, and in the 

 middle of the dorsal line with a small concavity. The seven ty|)ical 

 appendages are present, including three hairs, two "fingers" and two 

 digituli. The dorsal "finger" is only half as long and broad as ter- 

 minal "finger," which is half as long as the fourth joint, cyhndrical, 

 three times as long as thick, and rounded at tip. The two digituli 

 are somewhat longer than the terminal "finger" and are placed 

 close together. Penis with a relatively stout and short shaft with a 

 blunt point and with a slight prominence on the middle of the dorsal 

 outhne of shaft. (See plate 79, fig. 8.) Female pedipalp broader at 

 base than in male, second joint about twice as long as third one; 

 the terminal "finger" of the "thumb" is large, just equafing the 

 ventral side of the fourth joint, cylindrical and rounded at tip; the 

 digituli and hairs are similar to those of male. The tip of tarsus of 

 female, with a strongly curved empodial claw, which is four-cleft 

 beyond the angle, and four tenent hairs are borne on two enlarged 

 pedicels at the sides of the claw base. The male tarsus bears an 

 empodial claw that is very short, stout, and slightly bent, and is 

 tripartite beyond the angle. The collar trachea extends straight 

 down and is then bent in a round bow backward and upward without 

 widening to a noticeable extent at any point. 



