36 



BRITISH FLIES 



by a flap. It lives in wood. Cf. Brauer, pi. ii., f. 25 ; and Fiebrig in Zeitsclir. wiss. 

 Insektbiol., 1906. 



Fam. Leptid.e. Head exserted, but small ; behind it eleven segments, the first 

 of these bearing on each side a small spiracle. The terminal segment is about as large 

 as the preceding one, and is (in Leptis) marked by longitudinal folds or grooves ; the 

 two ventral of these ribs have slightly longer free tips, so that lieneath them there 

 is a small, cup-like depression in which the terminal two spiracles are placed ; these 

 fire rather small (and ai-e not accompanied by any chitinous plates as they are in the 

 somewhat similar larva of TinuUda-). The larva is amphipneustic. There are no 

 pseudopods, but on the ventral aspect of the body there is intercalated between each 

 tAvo abdominal segments an area that is a little prominent and Ijears some asperities 

 that assist in locomotion. The intercalation of these areas appears to cause the 

 purvate form usually assumed. The larva figured (fig. 60) is from the New Forest 





/-^-.-x 



Yvi. 50 — Pupa case of Xylornyia niaculata 

 showing the skin markings on one 

 sefrment. x 4^. 



■ -A 



1^ '•%ii.(?)» \ 



K-.; 



/ 



"mM 



Ay 



Fio. GO.— Young 



Le2^tis larva. 



X 12. 



Fin. 01.— Xijlophagvs 

 larva, x 4. 



and is no doubt that of Leptis, as it agrees with the larva from which Marchal reared 

 L. tringaria (Bull. Soc. ent. France, 1903, ]>. 234), the food being earthworms. 

 Atheri.r,iiCQOY(\mg to Brauer, has the terminal segment divided into elongate free 

 processes, and the intercalated areas of the abdomen rej^aced by jviirs of prominent 

 pseudopods. The larva of XyJophngns is so difterent that it requires special description. 



XylopluKjun (fig. 61). Head a hard, elf)ngate, and exserted pointed process. The 

 three thoracic segments with strongly chitiniscd areas dorsally, and the ]>rothoracic 

 segment is hard also beneath ; (these hard and colored areas are varial)le in extent). 

 There are eleven liody-segments. The terminal one has behind a large very strongly 

 chitinised area terminating in two strong hooks ; this area bears the two spiracles ; in 

 front of it, on the same segment, there are four bi'own marks. On tlie under surface 

 of this segment there is a peculiar hierog]yi)h, a brown circle with a hooked wing on 

 each side. At the front margin of each abdominal segment there is both dorsally 

 and ventrally a transverse area bearing very minute brown spines ; the dorsal series 

 being connected with the ventral by two lateral very delicate series of asperities. 

 This larva is amphipneustic, the thoracic spiracles being very evident. 



I have had before me I believe the larva of both X. cincius and A', ater, but have 

 not noticed any distinction. Brauer's figure (pi. iv., f. 83) of X. cinctus shows the 



