12. XYLOMYIA 223 



ending immediately after the tip of the wing ; discal cell with the discal and 

 lower cross-veins at about its basal sixth, the lower cross-vein being fairly 

 long ; the discal cell emits three veinlets of which the upper one is strongly 

 arched so that the first posterior cell is contracted just after its middle and is 

 more widely open at the wingmargin than at any other part, while the second 

 posterior cell is rather contracted at the wingmargin ; the second veinlet from 

 the discal cell is entire right up_ to the wingmargin ; basal cells equally long ; 

 costal vein continued as an ambient vein to the end of the second veinlet from 

 the discal cell. Squamaj (alar) obscurely whitish yellow with a very slight 

 pale fringe up to the lower angle, where there is a slight tuft. Halteres 

 orange, knob large. 



9. Very much like the male. Head just as in the male, but the antennae 

 rather less orange on the inside. 



Thorax as in the male, but the yellow markings usually smaller, so that 

 the humeral knobs are only partly orange and the spots at the sides of the 

 suture may be smaller ; the top of the sternopleurse and all the metapleurai 

 have slighter indications of orange, or the metapleurae may have a round 

 orange spot on their middle. Scutellum with a broader black base. 



Abdomen similar to that of the male, but the eighth and ninth segments 

 are quite obvious, while the orange hindmargins of the third to sixth segments 

 are narrower ; hindmargin of the seventh segment similar to that of the 

 sixth, but broader as it occupies half the segment at its widest part ; 

 eighth segment all orange except on the large transverse black middle basal 

 spot ; ninth segment all orange except on a large obscure middle basal 

 spot. Ovipositor with a pair of extended reddish orange lamellae which are 

 more than half as long as the ninth abdominal segment. Belly with the 

 yellow hindmargins very narrow up to the eighth segment. 



Legs with the tarsi and spurs darker, the basal joint of the front tarsi 

 having the apical half darkened.like the i-est of the joints, while sometimes the 

 middle tarsi are as much blackened as the front pair, and the hind tarsi may 

 have the tip of the two basal joints and the whole of the rest blackish ; the 

 spurs (especially the hind pair) may be blackish. 



Wings, squamae, and halteres as in the male. 



Length about 9 mm. 



This species varies a little in the size and extent of the orange spots 

 and markings, and the dark tip of the hind tibiae may be brownish rather 

 than black. X. trinotata Bigot from the Caucasus Mountains (according 

 to the female type in Bigot's collection) is rather allied and agrees in 

 the venation and the unarmed hind femora, but has the proboscis and 

 palpi blackish orange, the humeri and pleurae black, the thoracic suture 

 with very faint orange markings, the abdomen with scarcely perceptible 

 bands and even the end segments black, while the legs are reddish with 

 very slight darkening at the tip of the hind femora and tibiae, and the 

 hind tarsi are all darkened. X. tenthredinoides v. d. Wulp, which Osten 

 Sacken considered a dark variety of the North American X. americana 

 Wiedemann, is quite congeneric according to a specimen in Bigot's 

 collection. 



X. maculata occurs in the New Forest and was bred in considerable 

 numbers by Eev. H. S. Gorham in 1898, and since then on several occa- 

 sions by Dr D. Sharp, but the perfect insect has been seen by them on only 

 one occasion, when about the end of May 1904 one settled on a tree trunk 

 near Bank where they were collecting the larvae. It had been bred from 

 the same neighborhood previous to 1840 by Eev. F. W. Hope as recorded 

 in Westwood's Introduction to the Modern Classification of Insects, and 

 Stephens figured it in his Illustrations, vii., Suppl., 28, T. xlvi., fig. 3 



