284 Transactions of the Canadian Institute. [vol. ix 



each capsule is strongly excavated. The front margin of the bridge lies 

 but little behind the anterior end of the capsule and has an undulate 

 form, owing to the presence of two rounded prominences. The two 

 bristles on the bridge are moderately long and separated from one an- 

 other by 49/*. Breadth of bridge 66/*. The opening on the under side 

 of the capsule is of considerable size, extending laterad almost to the outer 

 margin of the capsule; its outer end presents an angular form. A dis- 

 tinct marginal thickening reduces the size of the opening. The anterior 

 eye-lens is not stalked and is short ovate in form; its two axes measure 

 37 and 32/t. The posterior eye lens occupies the usual position and is 

 ellipsoid in form (Fig. 4). It measures 64/A in length and 27/* in breadth. 



The capitulum including the pharynx has a length of about 450/t. 

 Its front edge is not emarginate but appears as though cut across, as 

 does also the antero-lateral margin next to the socket for the articulation 

 of the palpus ; and the structure has thus a markedly angular form when 

 viewed ventrad (Fig. 5). The outer margin of the oral area is almost 

 circular though flattened in front, its diameter measuring about 150/t. 

 The circular oral aperture is comparatively large, being 27/t in diameter. 

 The oral fringe (Mundkrause) has a transversely elliptical form. The 

 coarsely porous area of the maxillary shield extends almost to the hind 

 margin of the latter, while marginal areas of considerable width, extend- 

 ing almost to the oral area, are finely porous. The processes of the upper 

 maxillary wall are unusually stout, especially at the outer end; they ex- 

 tend caudad about as far as the hind margin of the maxillary shield 

 and are rather strongly divergent posteriorly. The processes of the lower 

 wall are directed upwards and backwards ; their free ends bent and slightly 

 thickened. 



The tracheal plates extend back to the posterior margin of the 

 pharynx; they are stout and their posterior extremities are strongly 

 thickened and slightly curved upwards. 



The pharynx has a comparatively moderate breadth behind (182/*), 

 and is narrowed anteriorly to a slight extent. The transverse arch 

 which is not far from the posterior end is but slightly chitinized. In 

 the region of its outer end the lateral walls of the pharynx are slightly 

 tumid. 



The mandible is about 158/1 long and 140/* broad; its basal segment 

 is narrowed proximad to io8/i at its posterior end. On the extensor side 

 of the two mandibles two small openings are distinguishable, one behind 

 the other. Of these the one that is immediately behind the terminal 

 segment is quadrate and equally broad at each end. The posterior ex- 

 tremity of the pair of mandibles, viewed from the extensor side appears 

 broadly rounded off. At the angle of the hind margin of the flexor side 



