260 



H. TETLEY. 



these, there are a number of very dark long hairs scattered irregularly over the 

 surface, and on this joint is an oval area of circular thick- walled cells. 



Wesche has laid down the rule that " the maxillary palpi when present in Diptera 

 are always in contact with the stipites and cardines of the maxillae," and in the 

 Journal of the Royal Microscopical Society for 1904 he gives a figure of a dorsal 

 view of the mouth-parts of a male of Pangonia longirostris, in which he marks the 

 palp as maxillary palp. The assumption from this would be that the palps are in 

 contact with the basal joints of the maxillae, but I did not find this to be the case 

 in the specimens I dissected, the palps arising, as stated above, from the soft 

 membrane adjoining the external border of the base of the galea. If Wesche's rule 

 be accepted, the palps should, in my opinion, be called the labial palps, but it seems 

 more likely that, from their close association with the maxillae, they are really not 

 labial palps, but maxillary. 



(3). Labrum-epipharynx (PL vi, fig. 5). — Strong, deeply chitinised in its basal 

 third, broad at the base and gradually tapering distally until, at a short distance 

 from the apex, it narrows more abruptly. It then widens out again, and again 



Fig. 5. 



Apex of labrum-epipharynx of $ ; 

 greatly enlarged. 



narrows, forming a somewhat blunt extremity. I have not been able to separate- 

 the labrum from the epipharynx, but in the preparations I have made I can see 

 clearly that there is a central portion which is directly continuous with the fulcrum, 

 and this I take to be the epipharynx, as described by Cragg in the case of Haematopota 

 pluvialis. The basal external corners of the labrum articulate with two strong 

 curved rods, which He in the wall of the head. The apex (text-fig. 5) is covered with 

 numerous rounded teeth which are directed backwards, and on the outer edges of 

 its base there are three ridges on each side, which run diagonally from the edge 

 towards the centre. Behind these ridges the teeth are continued for a short distance 

 on the edges of the labrum-epipharynx, but in the centre they pass gradually into 

 rows of minute hairs, which continue for some way down. A strengthening of the 



