Dipterous Genus Xyloinyia, Rond. 185 



amphipneustic, thus agreeing vvitli tlie larvie of Xylophagus, 

 but differing from those of Stratiomyicke. On each side, 

 however, of the first six abdominal segments, immediately 

 behind the tumid hvteral ridge, and so in the angle which 

 eacli segment forms with the next, I observe a small papilla. 

 On examining the larva-skin with a microscope I cannot 

 detect an aperture in any of these papillaj ; but it seems in the 

 highest degree probable that they represent stigmata which 

 liave disappeared, but were functional in the larvaj of ancestors 

 of the existing species of Xijlomijia.. At any rate, on ex- 

 amining them one is involuntarily reminded of the arrange- 

 ment of the stigmata in the larva of Actina tibialis, Mg., as 

 described by llandlirsch {loc. cit. p. 243), in which it is stated 

 that (besides the ordinary stigmata at each end of the body) 

 there is a very small stigma on each side of the first six 

 segments of the abdomen *. 



The body of the larva is nearly bare ; each postcephalic 

 segment bears a stout recurved yellowish-brown hair on the 

 tumid ridge on each side, and, in the case of the first ten 

 segments, a transverse row consisting of six similar hairs on 

 the dorsal side ; there is also a similar row of hairs on the 

 ventral side ; the eleventh segment has two hairs on the upper- 

 side, apparently four pairs beneath, and a pair, which curve 

 forwards, on the posterior margin — one on each side between 

 the lips of the stigmatic cavity and the posterior angle. 



The larva-skin (puparium) of Xijlomyia maculata agrees 

 very closely with that of the American Suhula pallipeSj Lw., 

 as described by C. H. Tyler Townsend (Ent. News, 1893, 

 p. 164), except for the absence of the transverse rows of 

 small tubercles stated by Townsend to occur on segments 5 

 (fourth postcephalic) to 11. In this connexion it is inter- 

 esting to note that the integument of the larva of Xijlomyia 

 varia {Xylophagus varius) , Mg., as described by von iloser f, 

 and that of the sixth and following segments of the larva 

 (larva-skin) of Xylomyia viarginata [Xylophagus marginatus), 

 Mg., as described by Wesmael J, also bear transverse rows of 



* llandlirsch appears to be unaware of the existence of the lateral 

 papillae in the larva of Xylomyia ; at any rate, he merely states {loc. cit. 

 p. 24.5) : — " In Hiihula it has not yet been determined with absolute 

 certainty whether the larva is likewise peripneustic, eiuco the stigmata 

 on the body are not easily recognizable, owing to the scale-like structure 

 of the cuticle." 



t Naturwiss. Abhandlungen, Stuttgart u. Tlibingen, Bd. ii. Heft 2 

 (18l>8), p. 188. 



X Cf. Ann. See. Ent. Fr. t. vi. (1837), Bulletin Entomologique, p. xc. 

 According to L. Dufour (Ann. Sc. Nat., Zoologie, S(5r. 3, t. vii. (1847) 

 p. 13), in the larva (larva-skin) of A', maryinata all the abdominal seg- 

 ments bear transverse rows of tubercles. This author writes: — "Lea 



Ann. ik Mag. N. Hist. Scr. 7. Vol. iii. 13 



