48 



criptions of Meigen (1818 p. 6) and Zetterstedt (1850 p. 3461) we always find 

 statements, relating to two black or brown lines running over the mesonotum; 

 these lines, more or less conspicuous, I have found upon all my specimens, but I 

 often miss them in the later descriptions. 



Meijere's description (1911 p. 144): a broad brown median stripe is in ac- 

 cordance with many of my specimens but this stripe is then often bordered by 

 lines frequently yellowish-white. This is also indicated by Edwards (1912 p. 218). 

 When Eckstein (1918 p. 65) states, that the last abdominal segment always pos- 

 sesses "Andeutungen von Schuppenbindern am hinteren Rande" I cannot verify this. 



From 0. vexans Meig. 0. cantans Meig. may probably always be distinguished 

 by means of the while tarsalbands which are always very narrow in the first 

 named species, whereas they are broad in 0. cantans; further 0. vexans Meig. is 

 of a very small size being only about 5 mm. whereas 0. cantans is about 7 — 8 mm. 

 Also the male genitalia of 0. vexans are very peculiar, the claspers being forked. 



The two species 0. cantans and annlipes merge with regard to the colour, and 

 are rather indistinguishable more especially in the autumn. The best character is that 

 the distal joint of harpago is flattened, about twice as long as wide in 0. anulipes 

 whereas in 0. cantans it is not much flattened and has a large, membraneous expansion 

 on one side. - - Resides the reader is referred to the description of 0. annulipes. 



Larva. Head rounded, strongly vaulted, large, wider than long, conspicuously 

 notched at insertion of antennae; front margin slightly arcuate. Antenna 3 short; spi- 

 nose, especially on the innerside, tapering at apex; tuft small, only consisting of a 

 few, about 7 hairs. Near the apex a long hair, three short hairs and a digit. 

 Anteantennal tuft short, multiple, lower frontal tuft with four hairs, upper double, 

 the hairs being very strong. Eyes large. 



Thorax subquadratic, angled at hair-tufts. Hair formula of frontal border 

 131114411131; tuft four consisting of one long hair and three very short ones; 

 hairs after tuft 4 always very short; the others strong. Lateral hairs in multiple tufts 

 and some single strong hairs. 



Abdominal segments broad, the first much shorter than the last. Lateral hairs 

 on the first and second segments triple, on the third to sixth double; subdorsal 

 hairs absent. The eighth segment with tufts in common arrangement; lateral comb 

 consisting of about 30 — 40 scales, arranged in rows, covering a triangular area; the 

 scales are spatulated at base, obliquely rhomboidal, bordered by long bristles; in 

 the middle a rather short spine, only insignificantly longer than the bristle nearest 

 to the middle thorn. 



Sipho about three times longer than wide; tapering at front, on basal third a 

 pecten highly developed, consisting of about twenty strong thorns with four or 

 live large teeth and some smaller ones at their base; a tuft of about six hairs 

 between end of pecten and apex. Anal segment almost isodiametric, ringed by a 

 plate. Dorsal tuft consisting of a tuft of short, soft hairs and two very long and 

 strong ones. Ventral brush in the barred area composed of about 16 rays, every 



