^y2 Syrphidae. 



parallel-sided, especially in the male, with three or four pairs of yel- 

 low or sometimes darker br bluish spots. The ventral segments 

 distinctly chitinised. In the niale there are five not transfornied seg- 

 ments, the first short and the fifth about half as long as the foregoing, 

 or smaller, Genitalia of the usual shape, turned to the right, the 

 ninth segment not large; on the ventral side all the transfornied seg- 

 ments, sixth to ninth, are visible. I the female abdomen shows six 

 visible segments, the sixth small, and further two more or less hidden, 

 the last ending with two small lamellæ. Legs somewhat slender, hind 

 metatarsi more or less thiekened, generally most in the male ; in the 

 male the legs show secondary sexual characters, generally to a high 

 degree, especially the front tibiæ and tarsi are dilated in various ways, 

 and also specially coloured; sometimes not the tibiæ but only the 

 tarsi are dilated; also the middle tibiæ are as a rule specially shaped; 

 fm-ther the front, or the anterior, femora are specially haired in the 

 male in various ways, and likewise generally the middle, or the 

 anterior tibiæ; otherwise the legs are haired as usual, with somewhat 

 long hairs on the posterior and postero-ventral side of anterior femora 

 and on the antero-ventral side of hind femora; tibiæ generally short- 

 haired, when not with special hairs in the male. The front tarsi are 

 also in the female a little broad and flat, and for the rest slight 

 traces of the special shape or hairiness in the male are also partly 

 found in the female; thus f. inst. the peculiar, white, tangled hair 

 found at the base of front femora in the males of many species, is 

 then also present in the female, but much shorter and smaller. Glaws 

 and pulvilli well developed. Empodium short, bristle-shaped and hairy. 

 Wings with the medial cross-vein before the middle of the discai cell. 

 Vena spuria distinct though not strong, with a more chitinised point 

 below the base of the cubital vein. Alula well developed. Alar 

 squamula with quite short simple hairs, thoracai squamula with long, 

 furcately divided hairs. Plumula densely haired with somewhat plu- 

 mose hairs. 



Platychirus is characterised by the dilated and specially shaped 

 front tarsi or tibiæ and tarsi, the special hairiness of the front femora, 

 and also often by the shape and hairiness of the middle femora and 

 tibiæ; these characters are only present in the male, but also the 

 females may be known by the front tarsi being, to be sure slightly, 

 broadened and tlattened; otherwise the shape of the abdominal mar- 

 kings, and partly the colour of the antennæ will separate them from 

 the females of the allied genera. 



Only little is known about the developmental stages. P. scutatus 

 is recorded to have been bred from rotten fungi (v. Roser: Wiirttemb, 



