4. NEMOTELUS 113 



living insect), but it does not vary much in the extent or distribution of 

 the markings except as mentioned above under the female. I cannot 

 believe that the specimens which have a black spot above each wing-base 

 are distinct, even though the distinct abdominal markings occur in those 

 same specimens, and consequently I cannot believe in Loew's 0. proxima 

 being anything more than a variety in which there are the same black 

 spots on the thorax and a somewhat different variation on the second 

 abdominal segment (on which Loew says the two black bands are united). 

 Sometimes the last annulation of the antennae and the arista are brownish ; 

 Brunetti (Entom., xxii., 84) stated that "a not uncommon variety known 

 " as collaris is yellow instead of green," but I have never met with that 

 name used elsewhere. Its metamorphoses have been described by Heeger 

 (Sitzber. Akad. Wien, xx., 1856). Some closely allied species occur in 

 European and Asiatic Eussia, but they have the belly much more black. 



0. trilineata is probably the commonest British species of the genus, 

 but yet is by no means common. I have records from Devon, Dorset, 

 Somerset, Hampshire, Sussex, Kent, Surrey, Essex, Cambs, Suffolk, Here- 

 ford, Glamorgan, Eenfrewshire, and Haddington, while Duncan says it is 

 common in Ireland. My dates extend from July 4 to September 2. 

 It is one of the commonest species in Europe, and is recorded from middle 

 Scandinavia to Sicily. 



Synonymy. — A variety, with clear yellow for the ground colour, represents Jlhisca 

 hypoleon of the Linnean Collection according to the specimen nearest the middle of 

 the label, the other specimen attached to the same label being 0. piilchella 

 {t. Haliday Stelt. ent. Zeit., xii., 137). Brunetti 's var. collaris was apparently a 

 name imposed by himself as I cannot trace it elsewhere. Lundbeck calls attention 

 to the fact that Briinniche described this species in 1761 but without a name, and 

 that Pontoppidan gave it the name of grceca in 1763 but gave no description. 



4. NEMOTELUS. 



Nemotelus Geoffroy, Hist, des Ins., ii., 542 (1764). 



Rather small flies of obviously black ground colour, but 

 usually with conspicuous white spots or markings in the male 

 which may almost cover the dorsal surface of the abdomen. 



Face very short in depth but conspicuously produced forward into a snout 

 (tigs. 118, 119), and the part of the frons just before the antennae often with a pair 

 of white spots which usually coalesce in the male ; mouth opening large and long, 

 with a long geniculate rather thin proboscis which bears small sucker-flaps; palpi 

 very small and thin, with a few little bristles at the tip. Eyes usually apparently 

 bare but sometimes distinctly hairy, large and very closely approximated on the 

 frons of the male, but small and widely separated on the frons of the female, and 

 while only the lower part of the back of the head protrudes in the male (in profile) 

 the head protrudes all round the eyes in the female ; facets on about the upper two- 

 thirds conspicuously dilated in the male in obvious contrast to the smaller facets on 

 the lower third. Antennae rather long ; two basal joints about equally long and 

 almost bare^ third joint elongate, pegtop-shaped, with four distinct annulations 

 and a two-jomted terminal style which ends in a very thin hair and which bears 

 about two minute hairlike plumes on its thickened part. 



Thorax almost quadrate but rather longer than broad, black with usually at least 

 a white spot on the humeri which may be connected by a thin line with a white spot 

 at the hind top corner of the mesopleurse, and these white markings give good 

 specific chai'acters in both sexes ; mesopleuriB with the usual bare space for the 

 reception of the front femora unusually large and depressed. Scutellum without any 

 marginal spines ; metanotum usually pubescent on its disc. 



H 



