Phalacrotophora. 419 



pointed; anal tube short, but somewhat high, yellow. Legs yellow, 

 hind femora dark at apex, with longish hairs below the basal half; 

 bristles on hind tibiæ of medium size; apical spur on middle tibiæ 

 long, nearly as long as metatarsus. Wings clear or nearly so, veins 

 yellow; costa about 0,39 of the wing-length, costal divisions about 

 as 12 — 5 — ^4; costal cilia long; fourth vein a little curved at the origin 

 and evenly curved towards the end. Balteres yellow. 



Female. Unknown. 



Length. About 2 mm. 



A. laeta is rare; Holte ^Vv and ^Vs 1918 (Th. Mortensen), only 

 two males. 



Geographical distribution: — Hitherto only known from Den- 

 mark. 



11. PlialacFOtopliopa Enderlein. 



This genus is very nearly related to and in most respects similar 

 to Aphiochaeta. The species are of black and yellow variegated colour, 

 only one species (the American halictorum Mel. et Brues) is black. 

 Frons high and narrow, from somewhat higher to twice as high as 

 broad; it is somewhat arched, generally shining, with an impressed 

 longitudinal middle line which is sometimes rather weak. There are 

 three transverse rows of bristles, the anterior row of which is char- 

 acteristic in the way that its inner pair of bristles is always much 

 below the outer and either nearer together or vertically below these 

 latter, near the eye-margin; the supraantennal bristles are generally 

 weak and small and are either two pairs, or often only one pair. Eyes 

 hairy. Antennæ with the third joint round, of the usual shape in 

 Aphiochaeta^ or it is elongated, oval and somewhat large; arista dorsal, 

 short or longer. Palpi generally smallish and generally with somewhat 

 short bristles. Postocular, oral and genal bristles as in most species 

 of Aphiochaeta^ viz one long lower postocular bristle, one oral and a 

 couple of smaller genal bristles. Thorax with one pair of dorsocentral 

 bristles. Scutellum with four bristles or the anterior pair quite small 

 hairs so that only one pair of bristles is present. Mesopleura generally 

 bare, in epeirae Brues (American) with bristles, among which one or 

 two longer. Abdomen in the male as in Aphiochaeta; the anal tube 

 of hypopygium with the apical hairs generally strong; as regards 

 abdomen in the female I shall describe it as it is constructed in the 



27* 



