Neoascia. 375 



arranged in the same way as in tiie SyrphusAarya. On the tapering 

 hind part of tiie body there are some brushes of spinules along each 

 side, and a little anterior to the spiracular process there is on each 

 side a small papilla directed backwards and terminating with one or 

 two hairs. On the ventral side the spinules of the dermis are smaller, 

 but on the abdominal segments there is here on each side a little 

 proleg-like group of small hooks on each segment. The colour of the 

 larva is dark yellowish or yellowish brown; the total length is 6 — 7 mm. 

 The pupa is similar to the larva, of the same size and colour, but 

 more arched, and with the dorsal side falling somewhat abruptly 

 downwards at the front end. Near the anterior end (on the first 

 abdominal segment) there are two cylindrical, yellowish white spir- 

 acular tubes, nearly 0,5 mm long; they are somewhat approximated, 

 directed forwards and diverging. Just at the anterior margin of the 

 pupa the small larval spiracles are seen. The pupa is attached to 

 some object with the hind part of the ventral surface just before the 

 attenuating part. 



The larva of N. geniculata w^as sifted from flood refuse in fens 

 on 1^/4 and ''^/4, it pupated and developed first in May; the larva of 

 floralis was taken in the same way at the end of April, it likewise 

 developed first in May; other larvæ were taken in the same way on 

 ^U, but as they were not bred I cannot say, to which species they 

 belong. According to the above dates the larva evidently hibernates, 

 but according to the dates of capture of the imagines and of copula- 

 tion of the various species it seems probable that there are more than 

 one brood in the year. I do not know what the larvæ feed upon, 

 probably microorganisms, for as there are no mouth hooks they cannot, 

 I think, feed on Aphides. The posterior spiracular process is able to be 

 telescopically drawn out and in, and the piaces where the larvæ were 

 taken were, to be sure, also humid, but the larvæ were not in water. The 

 larva is rather interesting, and there is all reason to think that Sphegina 

 has a similar larva, as these two genera are so nearly related. On 

 the other hånd the larva seems to show that these genera are in no 

 way nearly related to Baccha, \Yh\Qh has a leech-like larva similar to 

 the St/rphiis-\arYa. 



The species of Neoascia are characteristic by their narrow, some- 

 what elongated shape ; the genus contains the smallest of our Syrphids. 

 They occur in woods, thickets and fens on shaded, humid piaces, but 

 also on meadows, and they generally hover here in the low herbage. 



The species have been somewhat confused, at present 5 species 

 are recorded from the palæarctic region, of which 4 occur in Den- 

 mark. 



