112 



j\]r. F. W. Edwards on the 



described by Kellon;g simply as the " basal labial sclerife " ; 

 Frey honiold^izes it with the nientutn. I am by no means 

 certain that Frey's view is correct, since it usually shows a 

 median groove or suture, indicating that it may have arisen 

 by the fusion of paired structures. For convenience, how- 

 ever, it may be well to follow Frey. 



In Mycetophilid.E the labium consists of the two large 

 labella, usually two-jointed, attached to the mentum, at the 

 base of which an ill-defined sui)mentum is sometimes 

 discernible. Mycetohia diti'ers from all the other Myceto- 

 PHILID.E* in possessing at the base of the labium a large 

 hairy gular plate (figs. 2 c and 3 c) covering the forked end 



Fi-. 4. 



Under surface of head of {a) Ditomr/ia fascia t a, Mg., (b) P/afi/vra nemo- 

 rahsf, Mg., (c) Empalia vitripennis, Mg., (d) Phronia forcipula, 

 AViun. Note absence of gular plate, except in c; also great 

 development of the maxillary stipites in c and d. 



of the mentum t; to the anterior angles of this plate are 

 attached the bases of the maxillary stipites. The only other 

 Mvcetophilid in which I have found any gular plate at all is 

 Empaha vitrijjennis ; in this case the plate is very small, 

 bears no hairs, and is quite remote from the labium (tig. 4 c). 



* I have examined from this point of view the following species : — 

 Diadocidia ferrvginosa, Ditomyia fanciata, Symmei'us annidatus, Bolito- 

 j)/iil(i ciueiea, Macrocfra stiff ma, Phityura fai^ciata, P. ncmoralis, Myco- 

 inyia inscisuruta, Sciophila hirta, PJmpa/ia vitripeimis, Tetrayoneara 

 ty/vatica, Allactoneura cincta, Bo/etinn sciarina, Docosia valida, Leio- 

 myia sub/asciata, Phronia forcipula, Exechia fungorum, and Myceiophila 

 jmnctata. 



t It is possible that this " gular plate " is really the true mentum, 

 which in that case is absent in tne other Mvcetophilid^. 



