Empididae. 75 



are distinct, and Fallen and Zetterstedt have certainly never had it, 

 Strobl 1. c. has recognised both species, but takes them to be varie- 

 ties; such characters however as the thickened hind metatarsi (not 

 seen by Strobl) and the shape of the genitalia do not vary, and as 

 mentioned there are many other characters, and also the characters 

 from the colour I have found constant. Bh. umbripemiis seems also 

 to occur in spring, not as nigripennis during the whole summer, and 

 it seems to be a more southern species. 



21. Rh. variabilis Fall. 



1815. Fall. Dipt. Suec. Empid. 29, 33 {Empis). — 1822. Meig. Syst. 

 Beschr. III, 51,18. — 1842. Zett. Dipt. Scand. I, 407,23. — 1862. Schin. 

 F. A. I, 99. — 1903. Kat. palåarkt. Dipt. II, 231. 



Male. Eyes contiguous, the very small frontal triangle dark; 

 epistoma short, dark greyish. Occiput grey, with blackish, downwards 

 more brownish hairs. Labrum somewhat longer than, towards one 

 and a half times as long as the head is high, ferruginous or brownish; 

 palpi yellow with a long hair at the apex. Antennæ as long as, or 

 slightly longer than the head, brownish black, the two basal joints 

 with short hairs, the third long, attenuated towards the apex. Thorax 

 brown, dull, with three indistinct, slightly darker stripes, the median 

 broadest and most distinct, the lateral often disappearing. The dorso- 

 central bristles long, black, uniserial; no acrostichal bristles. One or 

 two humeral bristles, a posthumeral, generally three notopleural, one 

 or two supraalar and a postalar bristle are present, all long and 

 black; besides there are some shorter, bristly hairs, especially a tuft 

 on the humeri. Scutellum with four, rather strong, black marginal 

 bristles. Pleura grey, metapleura with strong, black hairs; the spiracles 

 brown. Abdomen brownish black, dull along the dorsum, somewhat 

 shining on the sides; it may be more or less translucently brown or 

 yellowish brown, especially at the sides; venter brownish, more or 

 less translucent. Abdomen is clothed with erect, black hairs; the 

 hairs at the hind margins of the segments much longer and stronger 

 than the others and hence very conspicuous; venter with short hairs. 

 Exterior genitalia small and inconspicuous, the lower lamellæ broad 

 and short, the upper somewhat styliform ; the end of the penis some- 

 times seen above as a thick thread. Legs somewhat long and rather 

 strong, yellowish or ferruginous, the apex of the tibiæ and the tarsi 

 dark brown or blackish; coxæ more or less greyish pruinose, the 

 front coxæ sometimes only to a slight degree. Femora mainly short- 

 haired, the anterior femora generally with some bristly hairs on the 

 dorsal and posterior sides; all femora with a few stronger bristles at 



