British Oribatidw. By A. D. Michael. 245 



dorsal skins flat on the abdomen concentrically, hence the concen- 

 tric horseshoe-shaped lines figured by those authors. The point 

 at the anal end of the abdomen is formed only by a projection of 

 thin chitine, and may break away without injury to the creature ; 

 it seems to me that Koch's canaUculatus, which is founded on a 

 single specimen fished out of water, may have been theleprodus 

 washed clean, and with the cast dorsal skins and anal projection 

 gone. The description, however, is not sufficient to make sure of 

 this. 



The constriction in the cephalothorax in Hermann's figure is 

 far too deep. 



The larva of this species, which I have bred, is very light 

 brown ; cephalothorax short and broad ; stigmata very open, pointing 

 upwards, and with a serrated margin ; stigmatic hairs short and 

 spatulate ; abdomen much and irregularly wrinkled, straight ante- 

 riorly, broadest in the middle, thence drawn out to a blunt point, 

 with two spatulate hairs ; anus long, and about central in the 

 abdomen ; being usually far forward ; legs very short and stout, 

 with spatulate hairs (see Plate X., Fig, 2). 



The nymph is almost similar to the perfect creature, but of 

 course with a smaller number of cast dorsal skins. 



GENUS DAM^US. 



30. Dam^us geniculatus. Linn. 

 Acarus geniculatus. Linn. vol. ii. 1025. 



Koch, fasc. 3, pi. 13. 

 Nic. 460. 



Damieus iorvus. Koch, fasc. 3, pi. 14. Nymph. 

 Notaspis clavij^es. Duges. 



Found everywhere ; very common under bark of dead trees, in 

 dead wood, &c. 



Great confusion has existed between this species and clavipes. 



31. Dam^us riparius. Nic. 

 Nic. 461. 



I found two specimens at Loch Maree of what I think must be 

 this species, although they are rather smaller than the size given 

 by Nicolet, and the sinuated anterior margin to the abdomen men- 

 tioned by him is hardly, if at all, shown ; in all other respects they 

 agree. I think it better to disregard these difi'erences, although 

 Nicolet relies on the sinuated margin, than to call these specimens 

 a new species ; the difi'erence may arise from locality. 



