34° DURHAM DIPTERA. 



XLIV. 574. 



20 (23). Abdomen with black points or marks at the sides. 



21 (22). Abdomen with two black marks. 



(2490. bipunctata, Mg.) 



22 (21). Abdomen with four black marks. 



(2491. quadripunctata, L.) 



23 (20). Abdomen without black spots or marks. 



24 (25). Hind metatarsus much thickened. 



(2501. tarsella, TAX,.} 



25 (24). Hind metatarsus not thickened. 



26 (31). Antennae yellow with the third joint black, or at least 



black at the point. 



27 (28). Palpi all yellow. ( 2 5<H. anisodactyla, Lw.) 



28 (27). Palpi yellow with black tips. 



29 (30). Bristles on the second abdominal segment not more 



prominent than on the other segments. 

 2492. Sapromyza obsoleta, Fin. 

 Bishop Auckland, 2 ?, July, 1900. 



30 (29). Bristles on the second abdominal segment distinctly 



longer than those on the others, especially in the 

 female. 



2503. Sapromyza apicalis, Lw. 

 Bishop Auckland, 1 % July 12, 1900, 1 ?, July 15, 

 1901. 



31 (26). Antennae wholly yellow, the third joint not black at 



the tip. 



32 (33). Palpi yellow with black tips. 



(2502. decipiens, Lw. 2498. albiceps, Fin.) 



33 (32). Palpi all yellow. 



34 (35). Two large warts on each side of the third abdominal 



segment. ( 2 5°5- difformis, Lw.) 



35 (34). Third abdominal segment without warts. 



2496. Sapromyza rorida, Fin. 

 Very common. 



36 (19). Wings with X.5 2 and the ends of V.2., V.3., and V.4. 



clouded. ( 2 497. prceusta, Fin.) 



