CALLIPHORA ERYTHROCEPHALA, MG. 293 



with the lower lever of T. oleracea and is clearly homo- 

 logous. To show the forked process at the posterior 

 end, indicating that the part is a fusion of two rods. 



Fig. 7. Ventral side of the labium of an undetermined Chiro- 

 nomus ; the situation of the lateral rods is practically 

 identical with that found in C. dorsalis, Mg. The 

 surfaces only of the paraglossae (labella) are drawn, and 

 consequently no tracheae are shown. To show the 

 lateral rods on the ventral side of the base of the 

 labium. 



Fig. 8. Ventral side of the labium of Leptis conspicua, Mg. ; the 

 labella (paraglossae) have been flattened out, and the 

 maxillae and maxillary palpi removed. The surface 

 only is drawn, and consequently no tracheae are shown. 

 To show the lateral rods, and for comparison with 

 Chironomus. 



Fig. 9. Mentum of Chrysopilus aureus, Mg., £ dissected out from 

 the ventral side of the labrum. The part is nearly 

 identical with that of C. auratus. F., but the latter 

 is without the separation of the rods in the median line. 

 Both these insects are nearly related to L. conspicua, 

 and the wing-venation is similar. To show the 

 presence of rods in the median line of the mentum, 

 generally found on the trophi in the Brachycera. 



N.B. — G. aureus is a small insect, and the part is 

 shown at a much higher relative magnification. 



Fig. 10. Mentum of Haematopota jiluvialis, L. ? (grey Clegg), 

 dissected out from the labium and flattened. To 

 show the absence of any median structure, the 

 chaetotaxy, and for comparison with Calliphora. 



Fig. 11. Mandible of Haematopota pertinens, Austen, $. This 

 Tabanid from British Central Africa is very closely 

 related to our H. pluvialis, and has been examined as a 

 control observation. 



