114 DR. J. E. T. AITCHISON ON THE ZOOLOGY OF 



are two parallel rows of granules which run obliquely backwards in the direction of, but 

 failing to reach, the median eye. 



The posterior keels, slightly converging in front, are almost continuous and in the 

 same straight line with the internal middle keels ; this slight want of continuity between 

 these two keels gives to them, when considered as one, a slightly sinuous appearance. 

 The area which is defined laterally by these keels, and anteriorly by a transverse offshoot 

 of granules from their anterior extremities, is depressed towards the middle line, finely 

 and sparsely granular for the most part, but quite smooth just in the middle ; this last- 

 mentioned smooth portion stretches from the ocular tubercle nearly to the hinder margin 

 of the cephalothorax, where it breaks up into a right and left branch ; each branch, ex- 

 tending towards the posterior angle of the intercarinal area, constitutes with the median 

 branch a T-shaped depression. The granules of the external middle keels are well marked, 

 but the posterior extremity of each is not connected by a conspicuous transverse row of 

 granules with the anterior extremity of the posterior keel of its side. The hinder half of 

 the cephalothorax is externally granular. 



Tergites. — Finely granular in the intercarinal and extracarinal spaces, the anterior 

 six provided posteriorly with three finely but bluntly denticulated keels. The keels, 

 which are very short on the first tergite, increase progressively in length, height, and 

 coarseness of granulation from before backwards; lateral keels slightly divergiug in 

 front, and becoming almost obsolete, as, curving outwards, tbey pass insensibly into the 

 granules of the lateral portions of the tergites. The median keel of the seventh abdo- 

 minal tergite present only on the anterior half of that plate, the lateral keels not reaching 

 the hinder margin of the tergite. 



Sternites. — First abdominal sternite marked with a few conspicuous punctures ; the 

 second, third, and fourth marked in the middle of the plate on each side of the middle 

 line with one puncture ; between these punctures there is a shallow depression ; the 

 fourth sternite furnished on each side with two low keels, — one, smooth, running from 

 the median puncture to the posterior margin ; the other, finely granular, running from the 

 inner end of the pulmonary aperture to the posterior margin. Fifth abdominal sternite 

 furnished with four granular keels, — two lateral, in the middle of the plate, falling short 

 of both the anterior and posterior margins, two median and parallel situated on the 

 hinder two thirds of its length. Between the last-named keels the sternite is smooth ; 

 the rest of it is very finely granular. 



Tail slender and long, more than five times as long as the cephalothorax, and more 

 than one and a half times the length of the trunk, thicker at the base than at the apex. 

 First segment with ten complete, finely and almost evenly denticulated keels ; the median 

 inferior intercarinal space smooth; the other intercarinal spaces finely and sparsely 

 granular, the spaces becoming slightly more granular from below upwards; superior sur- 

 face shallowly excavated. The second segment has the median lateral keel incomplete 

 in front ; the intercarinal spaces are almost wholly smooth, and the upper surface is less 

 deeply excavated than in the preceding segment ; the keels are evenlv and finely den- 

 ticulate. In the third segment the median lateral keel is absent, its place being taken 

 by a few minute granules ; the keels are evenly and finely denticulated, the superior 



