Pupa^ ii'C. 0/ Orphnepliila tesfacen. 635 



surface leading back to the mouth is membranous, and 

 exhibits at one point a setaceous area. The sides of the 

 labrum are membranous except for one chitinous plate (Jp), 

 at the anterior end of which are two coml)-likc groups of 

 long curving liairs (c//). Prcmandibular structures of any 

 kind are completely lacking. 



The mandibles {md, PI. VIII. figs. 14 & 15) are roughly 

 triangular, strongly chitinised, somewhat flattened laterally, 

 and coarsely denticulate. A large stiff brush of setns occurs 

 on the inner ventral margin, directed into the mouth ; three 

 slender sensory hairs are situated on the dorsal outer surface. 

 The maxilUe (lux. PI. VIII. figs. 14, 15) are fairly well 

 developed. A basal chitinous ring or band encircles the 

 maxilla almost completely ; the remainder of the walls are 

 membranous. Two groups of sensory papilhie (spp) occur 

 upon the upper portion, and two dense rows o£ serrated 

 set?e (ss) are situated on the anterior surface. The maxilhe 

 are attached by their dorsal margin to the mandibles much 

 more strongly than to the head, and for this reason the two 

 organs have been figured together. 



The Iabiu?n (PI. VIII. fig. 13) : the terminology of the 

 ventral and inner mouth-parts is so confused and uncertain 

 that I prefer to retain this name for the chitinous underlip 

 when it occurs as simply and distinctly as in the present 

 case, and 'Miypopharvnx " for the inner portion. The 

 labium is a nearly triangular plate of thick cliitin with a 

 row of blunt terminal teeth ; it is directed upwards from 

 the ventral side of the head at a sharp angle (text-fig. 2), 

 and is fixed and immovable. A membrane from its inner 

 surface proceeds back into the head, and returns as the 

 hypopharynx. 



The hypopharynx (text-fig. 2) is a fleshy organ lying 

 just above the labrum ; its anterior portion is bilobed, with 

 curious serrated chitinous thickenings and membranous 

 areas bearing sensory papilltC. The salivary duct opens just 

 behind this anterior portion on the dorsal surface. The 

 remainder of the surface of the organ forms the floor of the 

 mouth-cavity, and is continuous with the pharynx. 



The pharynx is strengthened above on either side by 

 a pair of large, sickle-shaped, striated lamellse (text-fig. 2, 

 l.,pl). The members of each pair are closely appressed, 

 the outer being connected with the hy^popharynx, and the 

 inner with the labrum. A similar condition exists in the 

 larvfe of PtychopteridcT, Rhyphidie (Keilin, 1912), and 

 Culicida3 (Johannsen, 1903), but the two pairs are always 

 more or less widely separated in the middle, rcmaining 

 joincd at their extreuiities. 



