EXPEDITION ANTARCTIQUE BELGE 



on drying after being soaked in spirit or other liquid, which does not occur in fully chitinized 

 Oribatidse. 



Céphalothorax broadly conical and without markings ; the posterior half has a depressed 

 and flattened latéral expansion on each side which is excavated for the insertion of the first 

 and second pairs of legs. Mandibles powerful, tridentate, the terminal tooth of the moveable 

 arm of the chela is the longest, the two distal teeth of the fixed arm about equal in length. 

 Second joint of the palpus almost as long as the three distal joints. Maxillae powerful. Lamellse 

 almost obsolète ; they are long, advancing far forward, but are mère thickened ridges so 

 little raised as to be easily overlooked. Rostral hairs rather near together, long, reaching 

 beyond the distal ends of the genuals of the first pair of legs ; stiff, straightish, slightly rough. 

 Interlamellar hairs near together, very long, longer than the céphalothorax, but quite perpen- 

 dicular, straight, stiff, rough, dark-colored, gradually deminishing in thickness. Lamellar hairs 

 similar in character but much smaller ; they are very near together and are perpendicular. 

 Pseudo-stigmata latéral, very inconspicuous ; almost in a transverse line with the interlamellar 

 hairs. Pseudo-stigmatic organs with small, almost globular heads on very short peduncles. 



Legs rather long for the genus ; the femora of the first pair almost reach the tip of 

 the rostrum ; the tibia? are the longest joints and are flattened and parallel-sided ; the femora 

 are the next long; almost as long as the tibiae and similar in shape ; the tarsi shortish. 

 The hairs, except those on the tarsi and the tactile hair of each leg, are thick and mostly 

 curved ; there are two on the inner and one on the outer side of each fémur of the first 

 two pairs of legs, one pair on each genual and a few on the other joints. The hairs on the 

 tarsi are more numerous, and are setiform and flexible, some of the terminal ones slightly 

 hooked. Claws tridactyle and strongly heterodactyle. 



Abdomen oval, with a pair of slight indentations in the hind margin near the middle ; 

 in each of thèse a short stiff hair is situated. Xotogaster arched, but not strongly so ; the 

 arching is more in the central than the peripheral portion, but there is not any distinct 

 démarcation between the two. The flattened marginal portion bears numerous low, irregular, 

 slightly polished ridges, quite uncertain in form, but arranged more or less radially ; there 

 are not any markings on the central part of the notogaster except the granulations. There 

 is one pair of very short, stiff hairs on the hind margin in addition to the pair above- 

 mentioned, and a few on the latéral margin. Génital aperture placed between third and 

 fourth pairs of legs, large and almost circulai- but with a slight tendency to be straightened 

 posteriorly and pointed anteriorly in the female ; smaller, and more mitre-shaped in the 

 maie. Anal opening about as far behind the génital opening as the radius of the latter ; 

 elliptical or oblong ; considerably longer than the génital opening ; its posterior end is about 

 half its own length from the hind margin of the abdomen. There are numerous shallow 

 ridges on the ventral surface mostly arranged in rough concentric circles round the génital 

 opening, but very irregular. There is a row of short thick hairs on each side of the anal 

 and génital openings ; a few smaller on the anal and génital plates, and some others on the 

 ventral surface including a curious transverse row of 5 to g longish hairs between the génital 

 and anal apertures of the maie, but only one pair of thèse hairs is présent in the female. 



The nymph. In company with the adults of this species were found a number of 

 spécimens of what might easily be described as a separate species (and genus) but I hâve 

 little, if any, doubt that they are the nymphs of the species now being described; of course 



