1862.] 155 



stout, whitish, fleshy basal joiut. divided iu two by a horny ring; second 

 joint cylindrical, horny; third joint much shorter (it bears a bristle, ac- 

 cording to Dufour; my specimens, preserved for years in spirits, may 

 have lost it.) However, even the rudimentary antennas of the other genera, 

 when viewed from above, show on the fleshy tubercle an indistinct circle 

 or ring, probably the indication of a joint. 



B. Ocelli. Bollfophihi and Mi/cctophil(( (m in figs. 1, 11 and 12) 

 show on each side, below the antenna, a small, pellucid, convex spot, 

 which may be an ocellus, and has been taken for one by Dufour. The 

 other larvae have either no such spots at all, or opaque, black spots in their 

 stead. 



C. Trophi. The trophi of the larvae of the M//cetophilulse consist of 

 all the parts forming the normal type of the insect mouth : the lahriim, a 

 pair of horny mandUjlcs^ a pair of maxillse^ and a lahium. 



1. Lahrnm. It is a fleshy piece, encased in a kind of horny frame, 

 which is fastened to the epistoma and interrupted anteriorly. Fig. 13 

 represents the labrum of Mijcctophlla slgnata ; d is the fleshy part, c the 

 horny frame, the inner margin of which is fringed on the inside, towards 

 the tip, with a row of very minute, stiff bi'istles. The labrum of the other 

 genera has precisely the same structure ; it is somewhat smaller in Bolito- 

 phila (fig. 9, (J) ; in Sciophila, and in the larva which I take to be L<'ja. 

 the epistoma shows a distinct depression in the middle. In all these 

 larvae the labrum occupies a considerable portion of the upper part of the 

 mouth, its tip, in repose, resting between the inner sides of the maxillae 

 (see (7, in figs, 1-4, 6, 7, 9 and 11.) Its function seems to be, princi- 

 pally, to shut the oral orifice, and perhaps to press on the mandibles and 

 maxillae during the process of mastication. 



2. Mandibles. They are horny lamels, serrated or indented on the 

 inside, and attached at two points to the horny shell of the head, that is, 

 to a horny projection of this shell, generally existing close by the antenna 

 (fig. 11, r) and another point a little below it, so that a vacant space, 

 already mentioned above, remains between the lower edge of the mandible 

 and the horny shell. The mandibles are compressed between the labrum 

 and the maxillae, and their indented edge is more or less closely applied to 

 the indented edge of the maxilla (/■■ in figs. 1, 3, 5, 7 and 11 ; fig. 5 shows 

 the position of the mandibles of S<'i(ir<L after the removal of the maxillse). 

 It results from this description that, differing from the usual situation of 

 the mandibles, here they are in a more or less oblique position towards 

 each other. 'Y\\e form of the mandibles differs in different genera. Those 

 of Mj/<-. Hi(jii(it(( (fig. lo) have a thin, rounded, serrated inner edge and a 



