6. STRATIOMYS 157 



and when these spots are long they slope outside the antennal prominence • 

 jowls decidedly broad and bearing similar pubescence to that on the face, and 

 similar pubescence extends on to the lower part of the back of the head away 

 from the broad eye-marginal collar ; back of the head considerably inflated 

 behind the eyes on the lower half but not so much on the upper half, but still 

 on this upper part forming a black collar ; this front part of the back of the 

 head close against the eyes bears a minute adherent glistening pubescence 

 which is yellowish white on the lower part and white on the upper part, and 

 this glistening pubescence points forwards about the middle and upwards on 

 the upper part ; right at the back of the head behind the vertex there are 

 numerous long thin pale grey liairs ; vertex with a pair of large orange spots 

 on a thin rim between the vertex and the occiput but usually rising from the 

 flat part of the vertex just before the raised rim, and these spots are rather 

 near together at the middle and almost extend to the hind corners of the 

 eyes, and they are bare in front, while behind they extend a long way down 

 the back of the head and form two large triangles almost united but separated 

 by a darker orange (or very rarely blackish) stripe, and bear some of the long 

 thin pale grey hairs of the back of the head. Eyes quite bare, shining 

 blackish, in life colored as in the male but with the band a little above the 

 middle and the dark bluish lower part larger ; facets all equal. Antennae as 

 in the male. 



Thorax, scutellum, and pleurai with more conspicuous denser^ shorter 

 woolly whitish grey or pale brownish grey pubescence. Scutellum with more 

 than the tip half reddish orange, leaving a broad arched black basal band. 



Abdomen rather more shining black than in the male, because the 

 pubescence is much shorter and less conspicuous on the disc ; this short 

 pubescence is almost blackish on the disc, but is more conspicuous because 

 more pale grey on the fifth segment, and the pubescence is longer and 

 yellowish all round the margin and especially about the shoulder corners. 

 The orange spots are rather larger, and sometimes the basal pair are so large 

 as to extend right up to the shoulder points, and not at all uncommonly each 

 extreme basal corner of the second segment bears a small isolated inconspicu- 

 ous orange spot : at other times the basal pair of spots are more triangular, 

 while the second and third pairs are always more conspicuous than in the 

 male and are more lunate, i.e. their inner ends are more widened upwards ; 

 the extension of the first and second pairs of spots on to the sidemargins of 

 the next segment is larger and extends more on to the disc at the extreme 

 fore corners of the segments. Belly with much shorter and less conspicuous 

 pale grey pubescence, and consequently the yellowish white cross-bands more 

 sharply defined, and the one on the hindmargin of the fifth segment usually 

 broader. 



Legs as in the male, but the tarsi less obscured about the tip. 



Wings as in the male. Thoracal squamje and their pubescence more dull 

 pale yellowish. Halteres sometimes rather darker. 



Length about 13-5 mm. 



This species varies considerably in the colour of the pale markings and 

 spots, which range from bright yellow to reddish orange, probably from 

 the varying maturity of living specimens and from the effects of time in 

 museum specimens ; it also varies a little in the size and shape of the 

 dorsal abdominal spots and the ventral bands, but not enough to cause any 

 doubt as to the specific identity of specimens. Continental specimens in 

 Kowarz's collection are clearly the same species, but the pubescence is 

 rather browner and the abdominal spots darker orange, while the ])\\- 

 bescence on the frons is rather conspicuously whitish grey; the line of 

 pubescence between the eyes is greyer, and the pubescence on the vertex 

 and occiput has a tendency towards tawniness. 



S. furcata is the commonest species of the genus in Britain, but yet is 

 rather local ; I met with it in considerable numbers near Felixstowe on 

 July 7, 1894, when it occurred on large Umbelhferous blossoms which 



