BRITISH FLIES 



39 



Fam. PiPUNCULiD.E. Larva acephalous and with very indistmct parts of the 

 mouth : segmentation obscure, but the segments probably ten or eleven : amphi- 

 pneustic, anterior spiracles small, posterior conspicuous, placed close together, not at 

 the tip of the l^ody, but some considerable distance Ijefore it. Puparium provided 

 with spiracular tubercles on the second (1) segment, and with or without more 

 anterior minute spiracles. Posterior spiracles as in larva. Dehiscence of the pupa 

 occurs by detachment of the dorsal plate, through which the spiracular horns project. 



Fig. OS. — Pipimnihu jxwalor larva and P. Kochdci puparium, shuwing the dehisced dorsal plate 



bearing the spiracular horns. [After Perkins 



^s-m, 



The larv;\3 are parasitic, living in the interior of other insects, usually of Homop- 

 tera. Our chief source of information about them is Pei'kin's Bull-exp. Stat. Hawaii, 

 i., 1905, p. 128, pi. vii. : Imt some important 

 points are not mentioned. 



Fam, Syrphid^. Larva apparently acepha- 

 lous ; of aliout eleven segments, but this point 

 often difficult of discrimination. The skin 

 usually rough (often pigmented, especially in 

 subfamily Syrphinre). Amphipneustic, the 

 abdominal spiracles placed (|uite close together 

 at the tip of the Iwdy ; the prominence some- 

 times very hard. In the case of Enstalime, 

 not hard, but forming a flexible tube that may 

 be capable of extension to several times the 

 length of the liody. Puparium with thoracic 

 spiracle-horns, that may be short or long, and 

 sometimes with smaller anterior horns that 

 mark the position of the larval spiracles. 

 The abdominal spiracles also prominent, and 

 usually but little different from the condition 

 they exhibit in the larva. 



The larvae of this extensive family show a 

 great range of variety in habits and in form. 

 The CJdlosia group inhabit vegetable stems, 

 etc., and Merodon bulbs ; a great many of the 

 SyrphincH are aphidiphagous. Eristalis larvte 

 are fond of the grossest filth. Xanthandrus 

 comtus attacks and devours lepidopterous 

 larvae, and Cacabumba pyrastri has been 

 reared from lepidopterous pupae. Notwith- 

 standing the large number of notices of 

 Syrphidce larvaB in entomological literature, 



there are but few good descriptions or figures, and I have been unable to form 

 intelligible diagnoses of the subfamilies from the larval characters. 



zl-A 





Fig. (59.- 



-Xylota sylvarum larva and puparium . 



X 7. 



