A. D. MICHAEL ON TWO SPECIES OF ACARINA. Ill 



very hard, clear cliitine at the points, and contmues so about a 

 third of its length ; thence it suddenly enlarges into a bulb, very 

 round on the outside, but flattened on the inner side, so that when 

 the two lie together they are flask or gourd-shaped. The upper 

 surface of the bulb is reticulated like the dorsal shield. The man- 

 dibles seem to be solely holding implements or nippers, as the two 

 joints which form the chelcB are much bowed and only touch at their 

 tips, but, as from their great length they would be liable to strain 

 and dislocation, a beautiful arrangement exists to prevent this — the 

 fixed penultimate joint, which is the upper one (Fig. 4,a), projects 

 a little beyond the moveable ultimate one, and has a strong bi- forked 

 or notched tip ; the inner point (Fig. 4,c) of the bifurcation is the 

 longest, and the tip of the moveable joint falling into the notch is 

 quite protected from all lateral strain. The maxillae are excessively 

 fine, sharp-pointed, acicular, retractile organs ; below them lies a 

 thin lingula, which, doubtless, with the maxillas, forms a sucking 

 tube. The palpi (PI. VI, Figs. 1 and 3,c) are large, and partially seen 

 from above ; they consist of four joints, of which the first is short, 

 the second much longer, the third the longest, and the fourth short, 

 conical, and ending in a long spine. The palpi bear sparsely 

 scattered fine hairs. There is a chitinous labium (Fig. 3) ending 

 in the lingula. 



The cephalothorax seen from above is nearly twice as broad as it 

 is long, and is divided into two parts — a posterior, almost oblong, 

 and an anterior, like an ornamental collar, lower in level, forming 

 the camerostomium ; its shape will be seen by the drawing. The 

 dorsal surface bears a pair of long hairs springing from little pits, 

 and standing upward and forward. These hairs are beautifully 

 branched or pinnate ; the branches or pinnules being sub-opposite, 

 far apart, and very fine. One of these hairs is shown at Fig. 7. On 

 the ventral surface the cephalothorax, as usual, extends much further 

 back. 



The legs are seven-jointed ; each leg is of nearly equal thickness 

 throughout — the first and fourth pairs are the longest, of about 

 equal length, the latter being a trifle the longer ; the two centre 

 pairs are of about equal length. The comparative lengths of the 

 difi'erent joints vary greatly in the different legs, and will be best 

 gathered from the drawing (PI. VI, Figs. 2 and 3). All the legs are 

 finely striated with transverse strise. The tarsi are curiously exca- 

 vated to receive the claws when thrown back. It is singular that 

 JOURN. Q. M. C, No. U. K 



