Bd. V: II) 



THE ACARI. 



17 



7. Zercon tuberculatus nov. spec. 

 (I'l. II, figs. S, 13, 15 & 16, lext-figs. 30— 33') 



Length 0,63 mm. Breadth 0,32 mm. 



Colour, yellowish-white. Shape of the body, elongated quadrangular, with slightly 

 convex sides; the greatest width between coxje II and III; at the anterior and the 

 posterior end squared-rounded; the hind margin with 4 — 5 pairs of small, hyalin, 

 conical tubercles (PI. II, fig. 16). 



The dorsal side covered by a single, week shield, which in some places exhibits 

 a net-like, scaly texture and by higher magnification is seen to be very finely 

 striated transversally. Hairs rather scarce, becoming longer towards' the posterior 

 end. The hind margin provided with one pair of small median hairs and two pairs 

 of long lateral hairs. 



Ventral side. 



Tritosteniuvi with broad, almost 

 cylindrical trunk, the anterior end 

 square, with a median incision; the 

 feathered slips very narrow, lanceo- 

 late, a little more than three times 

 as long as the trunk. Sternal shield 

 (Text-fig. 30) very week, partly fin- 

 ely punctured, posteriorly rounded, 

 extending backwards as far as to 

 the hind margin of coxa; III, with 

 three pairs of hairs. Ventral portion 

 very soft, with four pairs of hairs, 

 of which the posterior one is insert- 

 ed near the postero-lateral angles 

 of the body and extends far beyond 

 the margin. 



30 



3 3. 



Zircon tuberculatus Tgdh. nymphn. 



Fig. 30. Ventral view. 30 x . Fig. 31. Hypostoma. 620 x . 



Fig. 32. Ambulacre III. 620 x . Fig. 33. Ambulacre I. 



620 X . 



Anal shield square-oval, with net- 

 like texture, nearly contiguous with the 

 hind margin, with three small hairs. 



Behind coxa; IV are indications of nietapodial shields, finely punctured. 



Peritreniata (PL II fig. 13) very short, only twice as long as broad, situated 

 outside coxae IV. 



The epistoina (Text-fig. 31) triangular, with a long median projection; the out- 

 lines of the sides divided in two concave parts, one more deep proximal and one 

 more shallow distal. 



'°3*;o7. Schwedische Siidpolar-Expedition igor — igoj. 3 



