396 Syrphidae. 



basal part whitish, or it is yellow with black bands; in foreign species 

 both size and colour are much more various, the colour sometimes 

 bright metallic; in the densely pilose species the colour of the pile is 

 dominating, hidding the ground colour and much varied. Head a 

 little broader than high, as broad as or slightly broader than thorax, 

 excavated behind. Eyes touching in the male for a shorter or longer 

 distance, narrowly or more broadly separated in the female; they are 

 hairy in the male, bare in the female, or sometimes {inflata, non- 

 Danish) also hairy in this sex; the facets in the upper front part en- 

 larged in the male. Frons hairy, in the male small but protruding. 

 Antennæ inserted in the middle; the basal joints are small, the third 

 elongated, from two to three' times as long as broad; arista inserted 

 at the base of third joint, long, much longer than the antennæ, com- 

 pressed and plumose with long hairs, longest above; the basal antennal 

 joints have bristles at the apical margins, the third joint is micro- 

 scopically hairy. Epistoma hoUowed below the antennæ, with a large 

 and broad central knob in the middle and below it more or less but 

 not very retreating; it is thus somewhat protruding below and it is 

 more or less descending, sometimes rather long and of conical shape ; 

 the lateral angles are drooping below the front mouth edge. The 

 epistoma is reddish brown or yellowish and more or less densely 

 haired on the front side but bare in the hollow below the antennæ. 

 Jowls broad, a little descending; they are somewhat separated from 

 epistoma by a groove, stretching up towards the antennæ and separating 

 off narrow eye-margins. The oral aperture elongated; oral cone and 

 proboscis somewhat long; clypeus elongated, the basal part somewhat 

 long, the side lists stretching forwards are fine. Labrum long, strong 

 and strongly semitubular; the apical processes are of equal length, 

 the median somewhat cleft, densely beset with spines or emergences; 

 the upper lateral process thin, cylindrical and pointed; the lower 

 lateral processes are characteristic, they are, as usual, broad but the 

 end is roundly incised, the inner or upper corner drawn out into a 

 somewhat long point, the lower or outer corner also, but less, drawn 

 out; labrum has the usual lateral rows of small tubercles or papillæ 

 on the lower side. Hypopharynx is nearly as long as labrum, strong, 

 attenuated and somewhat pointed; it shows the special character that 

 it is beset with microscopical hairs in the outer part. The maxillæ 

 have the lacinia a little shorter than hypopharynx, only slightly curved, 

 otherwise of usual shape but the apex is rounded; they are in the 

 usual way beset with microscopical hairs; the palpi are not long, 

 considerably shorter than the lacinia, densely beset with hairs and 

 with some bristles at the apex, especially two very long. Labium 



