Tropidia. 481 



little shorter than labrum ; maxillæ likewise of usual shape, the lacinia 

 a little shorter than hypopharynx, its microscopical spines especially 

 distinct at the apex; the palpus a little shorter than the lacinia, with 

 microscopical hairs and some bristles. Labium with the basal part 

 and the oval labella of about equal length. Thorax rectangular; scutel- 

 lum black with the apical margin yellow, and w^ith a slight marginal 

 fringe below. There are no bristles present, but the postalar calli 

 have somewhat strong hairs, and at the margin of scutellum are long, 

 almost bristly hairs. Abdomen of the breadth of thorax, elongated, 

 somewhat narrowed behind; it is flat; in the male there are four not 

 transformed segments, the first short, the other three of equal length; 

 the fourth dorsal segment is about square or somewhat widened 

 behind, but the apical corners are bent down as rounded triangular 

 flaps; the fourth ventral segment is bent downwards and has a dense 

 brush of hairs at the hind margin to each side of the middle; it is 

 roundly incised in the front margin ; the fifth ventral segment is present 

 in its whole breadth, but quite short and quite hidden; the other 

 segments lying as usual on the left side and turned to the right ;^ 

 the ninth segment, the hypopygium, has elongated, triangularly spoon- 

 shaped, hairy, outer lamellæ, and long terminal appendages, hidden 

 under the fourth segment. In the female there are five normal ab- 

 dominal segments, the fifth small, the rest hidden, the last ending 

 with two lamellæ. Legs with the hind femora strongly thickened and 

 curved, and in both sexes with a triangular tooth below at apex on 

 the anterior side; hind tibiæ curved and somewhat compressed; the 

 legs almost quite short-haired, only middle femora with long hairs 

 behind; above on the trochanters a short bristle. Claws and pulvilli 

 well developed; empodium not quite small, spine-shaped, hairy. Wings 

 with the cubital vein curved a little down above the first posterior 

 cell (in the non-Danish fasciata distinctly looped); medial cross-vein 

 after the middle of the discai cell, rather sloping; anal vein dipped a 

 little downwards in the middle; radial vein with very fine hairs on 

 the basal part; no stigmatical cross-vein. Thoracai squamula with 

 long, branched hairs, alar squamula with shorter, somewhat flattened 

 hairs. Plumula quite short, with the hairs simple or slightly branched 

 at the base. 



The developmental stages were hitherto not known, but I have 

 examined puparia from which T. scita was bred. The puparium is 



I 



Verrall says (Brit. FL VIII, 128) that the genitalia are symmetricai, this is er- 

 roneous; they may look so seen from above, but they are principally constructed 

 as in other Syrphids. 



31 



