232 DURHAM DIPTERA 



XXXI. 396. 



2 (1). First abdominal segment with bristles. 

 1822. Siphona geniculata, Deg. 

 Marley Hill, 2 $, Wearhead, 1 $, Hesleden, 2 $, 

 Gibside, 1 $, August-September, 1896-1901, &c. 



Sub-Family Gymnosomiinle. 

 398. Cercomyia, Br. & Berg. 



1 (2). Thorax shining black, hoary in front on each side, 



and with two hoary stripes. 4 mm. 



(1824. curvicauda, Fin.) 



2 (1). Thorax with hoary tomentum, which encloses four 



slender black stripes. 6-8 mm. 



(1824^. thoracica, Mg.) 



Sub-Family Phasing. 

 ' 401. Alophora, Dsv. 



1 (2). X.5 2 nearer to the bend of V.4. than to X.4. ; stalk of 



0.4 2 , i.e., V.3 3 , rather short. (1828. he?niptera, F.) 



2 (1). X.5 2 at the middle between X.4. and the bend of V.4.; 



stalk of 0.4 2 , i.e., V.3 3 , long. 



3 (4). Dorsum striped. (1829. obesa, F.) 



4 (3). Dorsum entirely unstriped. (1830. pusilla, Mg.) 



402. Clytia, Dsv. 



1 (2). Antennae black. (j^i. continua, Pz.) 



2 (1). Antennae yellow. (1832. rotundiventris, Fin.) 



Sub-Family Trixinje. 



403. Trixa, Mg. 



1 (2). X-veins clear. (.^Zl' cilpina, Mg.) 



2 (1). X-veins clouded. ( J 834 cestroidea, Dsv.) 



406. Phyto, Dsv. 



1 (2). Palpi black. (1840. parvicornis, Mg.) 



2 (1). Palpi yellow, the tips often brown. 



3 (4). Abdomen with grey bands. 



(1839. melanocephala, Mg.) 



4 (3). Abdomen all shining black. (1841. nigra, Dsv.) 



