Explanation of Plate VII. 



number of sensory hairs on the edge. The under-sides of the labella 

 are partly chitinised, and similar conditions exist in P. concinna ; it 

 is indicated on both figures by the darker shading. 



The rod at the base is one of the mandibles which are in this 

 species separate, but embedded on the ventral side. The mentum 

 is but little developed, bvit in the Leptid genus Ghryso^nlus it will 

 be found in a condition very similar to those figured as 11, 12, 15, 

 with the median suture and the cleft process at the anterior end 

 Length li\ mm. or ^ inch. 



Fig. 9. One of the labella of Phora concinna, Mg. $ , to show the 

 trachese springing from a plate, and the great number of "taste 

 hairs " on the edge. The triangular process at the side is the 

 aculeation characteristic of the Phorid trophi. It consists of the 

 lacinise of the maxillae fused at their points. In Gymnophora 

 arcuata, Mg. and P. curvinervis. Beck. ( 5 only) the stipites and 

 cardines are also visible at this part of the mouth. Length * f mm. 

 or J J inch. 



Fig. 10. The labial palpus of P. concinna. To show the two 

 joints, a Nematocerous character never found in the Muscidse. 

 Length f mm. or ^ inch. 



Fig. 11. Mentum of L. Jlavicauda, dissected out from the mouth and 

 viewed from the ventral side, the anterior portion being uppermost. 

 To show the median suture of the part, absent in the Muscidse. 

 (Compare Fig. 13.) 



The bristles are also of interest, being exactly similarly placed 

 in P. curvi7iervis, Beck. ,^ . (Compare with Fig. 15.) Length t ™™. 

 or rhj inch. 



Fig. 12. Labium of Dolichopus griseipennis, Stan. Ventral side, 

 to show the mentum, witli the median process and the bristle-holes. 

 (Compare with Figs. 11 and 15.) Breadth, circa f mm. or ^V inch. 



Fig. 13. Mentum of Musca corvina, F. Shown in the same posi- 

 tion as the other figures of this part. On comparison with them it 

 will be seen that the median suture is wanting ; this condition is 

 always found in the Muscidse. Length at longest part -j\ mm. or 

 :iV inch. 



Fig. 14. The characteristic Phorid bristle; for comparison with 

 Fig. 16. Taken from the middle tibia of P. incrassata, Mg. 9 • 

 Length /^ mm. or xlxr inch. 



Fig. 15. Mentum of P. curvinervis, Beck., for comparison with 

 the part in other families. The sides are much developed and flap 

 over ; this is indicated in the drawing. Length fV mm. or ^^ inch. 



Fig. 16. Mycetophilid bristle, one of two on the apex of the hind 

 tibia of Sciara thomse, L. This structure is found only on the legs 

 of the Mycetophilidse. Length 'i\ mm. or ^V inch. 



