176 W. MILNE ON THE 



I believe this is the same animal as the one described by Mile. 

 Montet (9) as a variety of H. torquata, but left unnamed. 

 Habitat. — Draaifontein ravine pools. Abundant. 



Genus PLEURETRA Bryce. 

 Pleuretra reticulata sp. no v. 



PI. 13, figs. 18-18a. 



Specific Characters. — Of small size, widest near the middle and 

 tapering to both extremities. No spines on anterior border of 

 trunk. Dorsally, four transverse rows of spines on trunk, also 

 one pre-anal and one anal. One row ventrally near front of 

 trunk and two spines farther back. Rostrum has very long^ 

 setae, especially two laterally projecting ones. Antenna stout,, 

 about three-fourths of neck-width, with long setae. Teeth two. 

 Foot of four segments, narrow, with boss on first segment. Spurs 

 distinctive. Transverse ventral ridges nine or ten. Corona to 

 collar (minus flaps) 10 to 12 ; sulcus narrow with sharp peg-like 

 ligule. Upper lip rounded with a notch. Stippled. Size,. 

 l/120th inch. 



After examining this species carefully in 1914, and on looking^ 

 over some older notes, I found a set which I had completely 

 forgotten on this very animal. Thus I was furnished with a good 

 opportunity for comparison, all the more fortunate in that the 

 spined species are notoriously variable. Evidently this is a very 

 stable form, as the sketches are practically identical. It re- 

 sembles Macrotrachela aculeata in shape, and differs from the 

 other spined species in not having the clumsy rump. Its shape 

 is elegant in all positions, and the spurs, which are always seen 

 when it feeds, finish off the appearance well. It is beautifully 

 stippled over trunk, foot and spurs. 



At times it creeps quite fast with a glide, and moves more 

 quickly than the other spined species. 



The anterior border of the trunk has no spines. The trunk 

 has four dorsal cross rows, with eight spines each in the first,, 

 second and fourth rows, and nine in the third. There are four 

 spines on the pre-anal segment and four on the anal. Just above 

 the last two rows of spines there is, in each case, in the middle of 

 the segment, a double blunt short thorn. The ventral row consists. 



