HARRISON'; 



157 



tire; dorsal surface with no very characteristic features apart from the ehitinous 

 incrassations marking the inner limit of the antennary fossa. Undersurface 

 (Fig. le) characteristic, with distinct mentum and submentum, the latter having 

 a much raised gular portion, with strongly projecting truncated postero-lateral 

 angles, from which arise two very long hairs. Maxillary palps short, not 

 reaching margin of head. The antenna is four-jointed, of the usual 

 Amblyceran type. It is partially concealed by two comparatively 

 enormous broad-bladed spines. The first of these rises from the anterior border 

 of the antennary fossa, and projects backwards for nearly half its length. The 

 second is broadly based along the lateral margin of the fossa, and projects 

 backwards along the border of the raised gular area. A minute broad-bladed 

 spine also projects backwards from the clypeal angle. 



Text-fig. ii. Acantlwmenopon horridum d. 



Thorax. The prothorax is roughly oblong in shape, widest at the anterior 

 angles, tapering slightly posteriorly, and almost twice as broad as long. It 

 comprises a central raised portion and two prominent wings. No mesothorax is 

 visible dorsally. The metathorax is much shorter and a little wider than the 

 prothorax, and is narrowest anteriorly, widening to the postero-lateral angles, 

 thence obtusely rounded on the abdomen. 



Abdomen. Almost as broad as long. First segment reduced to a crescentic 

 tergite above, and a small sternite below; widest at fifth segment, thence taper- 

 ing rapidly; segments 2-8 sub-equal in length, segment 9 almost twice the length 

 and much narrower. (The concavity of its sides is exaggerated in the figure. 

 They should be almost flat). Stigmata on the pleura on segments 3-7. 



