230 Transactions of the Society. 



does so by the leg, and although a cheyletus might not be able to 

 make much impression on one of the Oribatidse, yet a chelifer would 

 probably be more successful. This protection of the legs is carried 

 to its highest perfection in Hoplojohora, where the legs are short and 

 project on the ventral surface near the hinder part of the cephalo- 

 thorax, which is only united to the abdomen by an articulation 

 allowing the former to shut down on the ventral surface of the 

 latter, the hood which covers the cephalothorax forming a hard, 

 close, box over the legs (which have been retracted), and the 

 various parts of the mouth &c., so that (the genital and anal plates 

 being closed) one unbroken, hard surface is presented to the 

 enemy, and it is amusing to watch the cephalotliorax being raised 

 and the legs cautiously making their appearance when the danger 

 is supposed to be over. 



In the genera Pelops and Orihata there is a chitinous flexible 

 wing-like expansion to the fore part of the edge of the abdomen, 

 projecting a little forward ; when any alarm occurs, the legs are 

 neatly folded against the body and this wing-like cover closed over 

 them, making the whole as snug and as slippery as possible. 



In the genera Tegeocranus, Notasjns, &c., the sternal plate or 

 the lower edge of the dorsal bears several strong projecting ridges, 

 leaving deep depressions between them into which the legs, when 

 folded up, exactly fit ; the leg generally being bent at the middle 

 joint, and one ridge lying within the flexure, so that the whole leg 

 can lie upon the under surface of the body, and be almost as well 

 protected as by the former methods. 



In Eremseus, &c., the coxse of the first and second pairs of legs 

 are set in deep indentations of the sternal plate open above and 

 below with strong projections between. I have observed that this 

 arrangement not only protects the leg, but also enables the creature 

 to raise it right over its back, which is useful to it, enabling it to 

 right itsylf when it falls on its back, as it frequently does. 



While treating of the modes in which Orihatid/B protect them- 

 selves, I may call attention to the singular habit which several 

 species, and the nymphs of others, have, of coating themselves with 

 extraneous matter; this is attained in various ways. In most 

 members of the genus Nothrus the back is concave, and dirt is 

 piled in the concavity ; in Damasus genicuJatus and D. clavipes, the 

 back, particularly in the nymphs, is provided with numerous long 

 hairs ; it is by some means plastered witli mud, which adheres to the 

 hairs, and indeed, it is not easy to get it ofi" without destroying the 

 creature. In Damseus pajnllipes and D. vertieiUipes a difierent 

 mode is seen ; the whole creature, including legs, and often each 

 individual hair, is thickly coated with white dust, so that the animal 

 looks as if it had been rolled in plaster of Paris. 



Another strange habit of many of the Oribatidfe, which also is 

 probably protective, consists in carrying on the back a pile, or 



