Aphiochaeta. 201 



bristles are so small that only one pair of distinct bristles is seen; 

 the iipper siipraantennal bristles may be either approximate or more 

 distant so that they are either more approximate than the inner 

 bristles of the middle row or placed in the same distance from each 

 other as these latter, and these are the two alternatives usually 

 occurring, but sometimes, however more rarely, they are placed more 

 widely apart so that they are more distant than the inner bristles of 

 the middle row; the siipraantennal bristles of the lower pair are gener- 

 ally more approximate than the iipper, rarely placed in the same 

 distance. Eyes hairy. Antennæ with the third joint generally round, 

 rarely more elongated, oval; it may vary a little in the relative size 

 in the various species, and sometimes it may be somewhat to much 

 enlarged in the male sex, but not or less in the female; arista dorsal, 

 shorter or longer, from distinctly piibescent to almost bare. Clypeus 

 generally or always a little more protruding in the female than in the 

 male, but not conspicuously. Palpi smaller or larger with generally 

 well developed bristles, sometimes the bristles more or less short; 

 in some few species the palpi are enlarged in the male and with the 

 bristles weak and short. Below the lower corner of the eye there is a 

 long lower postocular bristle, and then, stretching upwards along the 

 lower anterior eye-margin, a number of generally well developed 

 bristles representing the oral and genal bristles, but these bristles 

 form together with the postocular bristles an uninterrupted series 

 curving round the lower eye-margin, only the lower postocular bristle 

 being somewhat individualised by its size or its direction, and 

 this is sometimes also not the case either; not rarely this lower 

 postocular bristle is, however, distinct, and of the anterior row one 

 or a couple below are stronger, oral bristles, and by an interval 

 divided from the smaller genal bristles. Thorax with one pair of 

 dorsocentral bristles; in a couple of species {latifeniorata, ruficornis^ 

 errata) there is, besides, a bristle forwards and outwards to the dorso- 

 central bristles which may be termed an intraalar bristle; this bristle 

 is otherwise not individualised. Scutellum with two or foiir, in a 

 single case (flavicoxa) with six bristles; when there are two bristles 

 there are always two quite small hairs present, one on each side 

 anterior to the bristle, and it is these hairs which in the four-bristled 

 species have been developed to bristles; w^hen four bristles are present 

 they may either be equal in size or the anterior pair is smaller, and 

 not rarely they are equal in the female, unequal in the male; in some 

 cases the female shows four, but the male only two scutellar bristles, 



