32 Syrphidae. 



externally, but in some of the Syvphinae and in nearly all tlie others 

 they pi'otrude as shorter or longer anterior spiraciilar tubes, beset 

 with tubercles in various ways. The points through which they pro- 

 trude are often (perhaps alvvays) preformed in the larval skin; these 

 points He in the first abdominal segment. The genus Flatychirus 

 seems to stand somewhat intermediate as it has the spiracles pro- 

 truding, but so sb"ghtly that they are almost imperceptible. Just at 

 the anterior margin of the pupa the larval prothoracal spiracles are 

 often seen; they are generally small, but f. inst. in the Eristalinae 

 somewhat long. The opening of the puparium takes place in a way 

 characteristic for the family; two pieces are detached, both belonging 

 to the dorsal side; the lower piece stretches from the mouth opening 

 over a part of prothorax, over mesothorax and a part of metathorax, 

 the upper piece then continues over the rest of metathorax, the first 

 and second abdominal segments and a part of the third abdominal 

 segment; this latter piece has near its anterior margin the anterior 

 spiracular tubes, when such are present. As said it is only the dorsal 

 part of the segments which are detached. This mode of opening is 

 quite another than in other Cyclorrhapha, Avhere both dorsal and 

 ven tral parts are detached, and it is in connection with the faet, that 

 in the Syrphid pupa the mouth opening by the contraction has become 

 situated quite downwards at the lower anterior margin and is not 

 terminal as in most other cyclorrhaphous pupæ. Brauer has in his 

 work over the larvæ given a quite erroneous statement, as he says 

 that the lower side of the anterior segments by the contraction at 

 the pupation becomes situated terminally at the anterior end, while 

 it is in reality quite opposite. De Meijere has thoroughly described 

 and figured the facts for some Syrphid pupæ (Zool. Jahrb. Abtheil. 

 fur Syst. XIV, 1900, 122, Taf. 7, Fig. 37—39). Only in Microdon the 

 opening takes place in another way, as here three pieces are detached, 

 two upper separated in the middle line and with the spiracular tubes, 

 and one lower. — As the Syrphids have no frontal bladder the opening 

 must be caused in another way. Becher says (Wien. ent. Zeilg. I, 

 1882, 51) that it is caused by a widening of the epistoma (Unter- 

 gesicht); this is also so; when a pupa is taken out of the puparium 

 the epistoma is somewhat folded in, and it gets first its final, more 

 or less protruding shape by the opening of the puparium. — The 

 pupæ are generally found on the same piaces as the larvæ. — The 

 deposition of the eggs takes piaces on the piaces where the larvæ 

 live; the eggs of Syrphua are laid singly between Aphides on leaves; 

 those of Volucella have been found in the nests of Hymenoptera; 

 Eristalis deposites near the surface of water, Merodon in the earth 



