194 Syrphidae. 



are distinct mouth hooks; on prothorax are a pair of small prothor- 

 acal spiracular tubes, and dorsally at the posterior end a short, long- 

 itudinally somewhat divided posterior spiracular process. The colour 

 is greyish yellow with a dark, longitudinal, dorsal stripe and sonie 

 translucent reddish markings ; along each side is a pale reddish stripe. 

 The pupa is somewhat arched, of a conical shapé with the dorsal 

 side convex and the ventral concave; the head end is rounded and 

 it is somewhat, but evenly attenuated towards the posterior end; it 

 is thus not drop-like ; it is slightly transversely corrugated and has the 

 same posterior spiracular process as the larva, and the small larval 

 spines may also be detected ; above on the anterior part are a pair of 

 exceedingly small (0,06 mm) anterior spiracular tubes (as also men- 

 tioned by de Meijere, Zool. Jahrb. Abtheil. fiir Anat. XV, 1902, 679); 

 the tubes are thus only slight, scarcely detectible warts, and when 

 the pupa is preserved in alcohol they may be drawn back and are 

 not to be seen. The colour of the pupa is somewhat like that of 

 the larva but more effaced, and the empty puparium is whitish or 

 pale yellowish. The pupa has a length of about 6 mm. 



It is remarkable that I have found my larva under quite other 

 circumstances than the larva mentioned by v. Roser, and I am in- 

 clined to think there may be some error with his observation. Whether 

 the larvæ are aphidiphagous I cannot say, but I think they are, or at 

 all events carnivorous in some other way, as indicated by their mouth 

 hooks and as in accordance with the larva of Melanostoma. The larva 

 hibernates and pupates in spring in March or April; at the pupation 

 it fastens itself to a leaf or straw. 



The species of Platychirus occur in low herbage in fens and on 

 meadows, often near water, and also in woods; some species are 

 common near the shore on salt marshes. The genus is widely 

 distributed and goes far towards the north as species are found in 

 Siberia and in Greenland. Several of the European species occur in 

 North America, and Verrall is inclined to think that most or all 

 American species are identical with European. — It was remarked 

 above, that traces of the sexual ornamentation of the male are gener- 

 ally found in the females; in connection with this it is curious to 

 note, that hermaphroditic (or hermaphroditic looking) specimens seem 

 to be relatively common in this genus. Becker (Nov, Aet. Leop. Carol. 

 Akad. LXII, 1894, 249) has mentioned such a specimen of manicatus, 

 Wahlberg (Ofvers. Kgl. Vet. Akad. Forh. IV, 1847, 101) oi clypeatus, and 

 Villeneuve describes (Wien. ent. Zeitg. XXIX, 1910,81) a similar speci- 

 men of peltatus, which had the head as in the female, abdomen with 

 only three pairs of spots but with exterior male genitalia; the front 



