566 MESSRS. C. WARBURTON AND N. D. F. PEARCE ON [DeC. 12, 



Subfam. SERRARHNiE. 



Gen. Serrarius Michael. 



Serrarius microcephalus Nicolet. 



This interesting species, which Mr. Michael in his ' British 

 Oribatidse ' describes as occvu^ring rarely at Epping Forest, the 

 Land's End, and Swanage, was found in abundance in the autumn 

 of 1 904 in the moss of an osier-bed at Grantchester, Cambridge, 

 and several specimens of the nymph, hitherto unknown, were 

 discovered. This is a remarkable creature, entirely unlike the 

 imago, and has the habit of carrying on its back the cast larval 

 and nymphal notogastral skins (Plate XIX. fig. 3). As each of 

 these skins bears round its edge eighteen conspicuous spines, 

 proceeding from short apophyses, the fully-grown nymph has a 

 remarkably spiny appeai'ance. The colour is pale yellow and the 

 surface finely punctate. 



In 1879 Kramer (in the Archiv f. Nat., Jahrg. 45, Bd. i. p. 16) 

 described a new species of mite which he named Gustavia sol, 

 which, so far as we have been able to ascertain, only Oudemans 

 has suspected of belonging to the Oribatidse. He states that it 

 is probably the nymph of a Serrarius. A glance at Kramer's 

 figure at once makes it perfectly clear that he was dealing with a 

 tSerrarms nymph, and he even gives a drawing of the mandible, 

 perfectly characteristic in shape, but lacking the serration, which 

 is ahvays difiicult to see. He mentions no locality, and attributes 

 to the animal a size much too large (1'2 mm.) for either of the 

 known European species of Serrarius. Possibly the length given is 

 intended to include the legs. In any case, Gustavia sol Kramer 

 can now be stated to be a nymph of Serrarius, as Oudemans 

 suspected. 



Subfam. NoTASPiDiNiE. 



Gen. LiAOARUS Michael. 



Liacarus bicornis, sp. nov. (Plate XIX. fig. 4.) 



Adult. Length 600 ji. Colour red-brown. Surface highly 

 polished. Lamellse, large blades on edge, near together and 

 sub-parallel, but slightly converging anteriorly. Very long free- 

 projecting cusps, from the extremities of which proceed the long 

 lamellar hairs. Translamella and interlamellar hairs wanting. 



Pseudostigmatic organs long, filiform, curved upwards and 

 slightly outwards. 



Abdomen very globular, with rather piominent shoulders, and 

 with a few longish hairs. 



The coxa of the 4th leg is almost as long as the femur, and is 

 produced anteriorly in a pointed blade. 



Three specimens were found in moss from Austwick in May 

 1904, and one from moss from the river-bank near Ely, in July 

 1905. 



Nymph and larva unknown. 



