186 STRATIOMYID.E 



veinlet from tlie discal cell rather strong, the first one being faint and the third 

 one obsolete or incomplete. Alar squamse small, brown, with moderately long 

 pale fringes ; thoracal squamae almost concealed, club-shaped, rather yellowish 

 brown, and with long pale brownish-yellow pubescence all over. Halteres 

 dull yellowish brown. 



9 . Very much like the male. Frons shining blue green, at the vertex about 

 one-fifth the width of the head but narrowing from there to the ocelli, and 

 then it is almost pai'allel-sided down to the pair of conspicuous white spots, 

 after which it gradually widens until it is about as wide at the antennae as 

 at the vertex ; pubescence greyish from the vertex to the upper ocelli, but 

 black and nearly erect after them, and absent on and below the white spots ; 

 below the ocelli the rather narrow middle part is bare and polished down to 

 the white spots but the sides are widely pubescent ; in jDrofile the frons begins 

 to be elevated much before the white spots and thence to the antennae, and 

 the face bulges out a little ; face slightly wider than the fi'ons and with 

 parallel sides, and bearing longer and denser pubescence Avbich is outstanding 

 and not upturned ; back of the head very shallow and scarcely visible in 

 profile, but with a rim behind the eyes on tlie lower part of which is a short 

 black ciliation pointed forwards, and behind this a long conspicuous out- 

 standing whitish fringe all the way down. Antennae slightly longer than in 

 the male. 



Thorax and scutellum brilliant green, bearing short whitish pubescence 

 composed of moderately sparse nearly erect hairs and dense shorter sloping- 

 pubescence ; pleurae with longer and more conspicuous whitish pubescence 

 except on the bare polished part of the mesopleurse ; metanotum with 

 upturned hairs on its lower part. 



Abdomen purplish; ovipositor with a pair of protruded jointed terminal 

 lamellae which very much resemble those of the male except that they are 

 longer and thinner ; pubescence on the disc very inconspicuous, being com- 

 posed of very short dense adherent rusty black bristles, but all about on the 

 sides sloping, whitish, and short except at the sides of the two or three 

 basal segments. 



Legs as in the male. 



Wings very similar to those of the male, but paler about the basal third. 



Length about 8 to 10 mm. ; Becker gives ($ as 7 to 11 mm., ? 6 to 11 mm. 



This species is distinguished from all the European species except S. 

 cuprarius and S. nuhecidosus by the remarkable outstanding white postocnlar 

 fringe, while it is distinguished from those two by the absence of the 

 conspicuous cloud on the middle of the wings and by the more narrowly 

 ferruginous knees. It is very easily distinguished with the naked eye, 

 but not so easily by the lens, though the more darkened pubescence on 

 the upper part of the frons is a good character. These species may 

 probably be distinguished from the S. fiavipes group by the banding of the 

 eyes in life, but I have not been able to test this character. 



8. iridatus is rather common though seldom abundant, and appears to 

 be very widely spread over Britain as I have numerous records from 

 Penzance to Golspie, and also from several Irish localities. My dates 

 extend from May 15 to August 15. It is recorded from all Europe. 



Si/nonymy. — This si)ecies has been commonly known as S. infuscatus Meig., but 

 Walker in 1851 resurrected Scopoli's name of *S'. iridatus, which is probably correct 

 and of course has priority, though why Schiner after adopting iridatus in 1855 

 reverted to infuscatus in 1862 is unintelligible. It is perhaps as well that Scopoli's 

 name was revived, as otherwise the obvious synonym of Musca indicus of Moses 

 Harris (1782) might have claimed priority. In the synonymical notes under 

 .S'. cuprarius I have called attention to Loew's var. rohustus being obviously, and his 

 var. gracilis probably, varieties of S. iridatus, which was evidently a species which 

 he had not recognised in 1840. 



