106 STRATlOMYIDiE 



with the pale sides of the face. Face with conspicuous broad glistening whitish 

 sideraargins, and these margins are continued narrowly round under the eyes and 

 extend broadly and conspicuously up the lower_ third of the back of the head, 

 but the upper part of the back of the head is shining black, and the eye- 

 collar is as wide as a third of the eye ; pubescence inconspicuous but universal, 

 mostly very short and pale but longer about the jowls and brownish on the 

 f rons. Eyes almost bare ; facets all equal in size. Antennae brownish orange, 

 with the tip annulation and the arista dark brown. 



Thorax shining black, with the yellow side-lines on the top margin of the 

 mesopleur^e widening towards the wing-base and (as well as the postalar calli) 

 more extensively yellow, and in addition there is a pair of widely separated 

 whitish yellow straight lines on the disc extending from the extreme front 

 margin (where they are slightly widened) to more than half-way between the 

 suture and the hindmargin ; sternopleuree with a pale yellow spot on the top 

 corner. Pubescence all very short and depressed though rather abundant, 

 greyish white, but longer and whiter on the pubescent parts of the pleurae. 

 Scutellum more whitish yellow, with the spines yellow to their very tip._ 



Abdomen marked as in the male but with the yellow markings slightly 

 larger, and these markings vary very considerably on the fourth segment ; 

 usually the extreme hind corners of the second segment are yellow and united 

 with the triangular yellow spots on the third segment, and these latter occupy 

 all the sidemargins of the third segment and are connected along the side- 

 margins with the yellow spots on the fourth segment, and these spots on the 

 fourth segment may extend considerably more across the disc and are in their 

 turn rather narrowly connected with the large yellow triangle on the fifth 

 segment, which may extend right up to the foremargin of that segment ; the 

 spots on the fourth segment are sometimes narrowly united near the hind- 

 margin. Pubescence short, light grey, and depressed, but longer about the 

 basal corners. Ovipositor dull yellow, long and rather narrow when extruded. 



Legs very much as in the male, but the hind tibise less darkened. 



Wings almost as in the male. Squamae rather less blackish. Halteres 

 whitish, with the base of the stem blackish. 



Length about 5 mm. 



This species varies a good deal in the female in the extent and intensity 

 of the yellow markings on the frons and abdomen and to a small extent 

 in the dorsal lines on the thorax, but it may be distinguished from all 

 other European species by its moderate size, its forked cubital vein, its 

 connected abdominal side-spots, and its almost wholly yellow legs. 



0. pardalina is a rare British species of which I had seen only one 

 female specimen until 1901 ; that specimen was given to me by Dr T. A. 

 Chapman and was presumably taken near Abergavenny, but Pr J. H. 

 Wood has taken a considerable number of specimens in the neighborhood of 

 Tarrington in Herefordshire during the last few years, and Colonel Yerbury 

 has also taken it at Woolhope, Pembridge, and Cusop ; I know of no other 

 records except those given by Curtis and Dale from Dorset about seventy 

 years ago. Dr AVood has informed me that the species appears to like 

 the margins of small overgrown streams in hilly districts. The records 

 extend from July 9 to August 20. It is recorded from all across Central 

 Europe, but not from North or South Europe unless Zetterstedt's 0. 

 mandata is a synonym. 



Synonym]/.— T\ieve has been considerable confusion over the use of the name 

 jmrdalina, biit I accept Loew's interpretation of it when he described both it and the 

 allied species 0. amcena in 1857 ; nevertheless the solitary representative of 0. 

 amcena in Bigot's collection was a normal female of 0. parclalina ! Zetterstedt's 

 0. macidata may be a variety with the scutellum mainly black, and as his species 

 was described from one female only taken before 1837 in Lajiland it may well be a 

 small dark form of 0. jxo-da/ina. I cannot make anything of Walker's 0. jKinlalina 

 except a bad description of the true species. 



