156 [March 



second row of indentations, parallel to tlie first, on the flat surface of the 

 lamel, along the margin of its stronger portion (fig. 15, q). The man- 

 dibles of BoUtojihila resemble the former in their outline. Those of 

 Sciara are more square, and have only three or four large indentations at 

 one end (fig. 16) ; those of Sciopliila are uniformly thin, slightly con- 

 cave, with several large indentations, and some minute ones in their inter- 

 vals and on the surface (fig. 17). 



3. Maxillse (figs. 18 and 19). They consist of a triangular cardinal 

 piece (x x in the figs. 1, 3, 7, 8 and 18) and a sfijjcs composed of two dis- 

 tinct pieces : 1st. An inner one, which is generally connected with the 

 cardinal piece below by a horny process (o in figs. 18 and 19) and ends 

 above in a coriaceous, more or less cultriform lobe, serrated on the in- 

 side (z). 2d. An outside one, (d'') which is horny, and has near its tip 

 a round excision (i) for the palpus. The cardinal piece of one side is 

 generally separated by an interval from that on the opposite side (as in 

 Mi/cetopliila^ Sriara, Sciojdida ; see the above quoted figures) ; but in 

 the larva which I suppose to be that of Lcja^ they are remarkably large 

 and contiguous (fig. 8, xx^. The serrated lobe offers much analogy of 

 structure in all the larvae which came under my examination ; in Myceto- 

 phila, its edge had 10 or 11 sharp indentations, which become smaller 

 and indistinct towards the tip. The Sciarse showed only 6 or 7 such in- 

 dentations, of which four were larger and less sharp than in Mi/cetophila, 

 the other 2 or 3 were small and rounded ; in Sciophila the serrated lobe 

 is elongated, narrow and curved ; the indentations are distinct only at the 

 base; in Bolitophila (fig. 19) on the contrary, the lobe is short, rather 

 stout, with sharp indentations. The horny process o is particularly de- 

 veloped in this genus, being strongest and showing a distinct excision 

 immediately below the first tooth of the cultriform lobe (fig. 19). The 

 horny outside piece of the maxilla (d' in figs. 18 and 19) is closely applied 

 to the inner one (see A, figs. 1 and 3, showing the maxillje of Mycetophila 

 and Sciara in their relative position to the other parts of the head) 

 although not soldered to it (a slight pressure between two glass plates 

 easily separates them, as fig. 18 shows.) A small fleshy tubercle, pro- 

 truding through the round opening at the tip of this piece, is evidently 

 a rudimentary maxillary p(dpu>i (/'), which I have seen developed only in 

 Sciophila (fig. 7, /) where it is subuliform and apparently two-jointed. 

 The round excision is unusually large in this genus. The rudimentary 

 palpi of the other genera, show under a strong magnifying power a minute 

 horny ring in the middle of the excision (as in tig. 18) which may be the 

 indication of a second joint. In two Sciarse which I dissected, the hoop 



