DURHAM DIPTERA. 383 



LVI. 658. 



50 (49). Frons all or mostly black. 



51 (52). Wings clear; veins nearly colourless. 



(2820. clunifies, Mg.) 



52 (51). Wings brownish with distinct brown veins. 



53 (54). V.4 3 at least as long as X.5 2 . (2818. erratica, Hal.) 



54 (53). V.4 3 only as long as X.4. (2821. heteroneura, Hal.) 



55 (48). Legs black, at most the fore and mid coxse pale. 



(2827. coxata, Stnh.) 



Family LVIL— PHORID^. 



Becker's monograph, on which the following tables are 

 founded, should be consulted by those who read German. 



The wing veins of the Phoridae (V. 35) are probably as 

 follows, counting round from the base of the fore margin : — 

 V.I., V.2., V.3., thick-veins; V.4.a., V.4.b., V.5., V.7., thin- 

 veins ; V.6. is undeveloped, although the base may be detected. 

 But for the purpose of the following tables, account is chiefly 

 taken of the lower thick-vein, called V.3. (which is said to be 

 forked when the end of V.2. shows itself, as in Plate V. 35), 

 and of the upper thin-vein which is simply called V.4., 

 although it is probably V.4. a. If in Macrocera (IV. 6) the 

 lower portions of the third, fourth, and fifth veins were 

 crushed together, an arrangement would be produced not 

 unlike Phora (V. 35). 



The arrangement of the head bristles is also most im- 

 portant. In the principal genus, Phora, they consist of 

 14-16 strong bristles, 12 of them arranged in four perpen- 

 dicular rows of three bristles each, or three horizontal rows 

 of four bristles each. The two side rows each consist of one 

 vertical and two fronto-orbital bristles. The two middle rows 

 are formed of one pair of post-vertical, one pair of upper- 

 frontal, and one pair of lower-frontal bristles. These all point 

 backwards over the head. In addition there are 2-4 still 

 lower frontal bristles, immediately above the antennas, which 

 are here called the post-antennal bristles, and numerous hairs 



