SCOTT— MALLOPHAGA, APHANIPTERA, AND DIPTERA PUPIPARA 



165 



base, but when the segment is viewed from a slightly different angle its length appears a 

 little greater than its breadth at the base : the anterior half of the segment is bare, but 

 the posterior half bears a number of short erect bristles : there are numerous rather 

 longer erect bristles on its sides, and there is a long stout bristle at either apical angle. 

 Yentrally (fig. 4), the basal sternite is bare towards its base, but has several irregular 

 series of short bristles on its surface behind, and rather longer bristles, directed outwards, 

 at the sides : teeth of the ctenidium rather long. Sternites 2 and 3 have alternating 

 moderately long and shorter bristles on their hind margins, and at the hind angles 

 several much longer bristles, of which one is very long and outstanding : the surface 

 of sternite 2 is almost hidden under the ctenidium, but some very short bristles can 

 be discerned on it : the surface of sternite 3 is bare except for a few very short bi-istles 

 just in front of the hind margin : both sternites have a few rather longer bristles 

 on their surfaces towards the lateral margins. The next sternite (4 + 5) is a plate as long 

 as, or longer than, the two foregoing taken together ; its margin is curved at either side, 

 so that it forms roughly a trapezoidal figure : its surface is bare except for a narrow area 

 immediately before the margin : the apical part of its margin bears a number of stout 

 black thorn-like bristles, immediately in front of which is a series of very fine bristles, 

 long and short alternating : the sloping parts of the margin on either side bear very long 

 bristles, immediately in front of which (on the surface) are short erect bristles, and in 

 front of these again some very short bristles. The anal segment is rather densely covered 

 with stiff erect bristles : the claspers lie parallel but not contiguous, taper from base 

 to apex, and are black-pigmented not only at the apex but throughout their length almost 

 to the base. 



The $ ABDOMEN dorsally (fig. 1) is very remarkable. Basal tergite small and narrow, 

 frequently appearing much foreshortened owing to distension of the abdomen, narrower at 



2. 3. 4. 



Figs. 2 — 4. Nyeterihia (Acrocholidia) fryeri, sp. nov. 2. ? , thorax and abdomen, ventral. 3. $ , abdomen, 



dorsal. 4. $ , abdomen, ventral. 



the base and broader behind, with the hind angles rounded ; divided in the middle of the 

 hind margin by a triangular cleft extending forwards about half its length, in which cleft 



