DURHAM DIPTEEA. 191 



XXVIII. 288. 



48 (47). Abdominal bands not duplicated. 



49 (50). Abdomen with a pair of basal spots and one band. 



bifasciahis, above (1531) 



50 (49). Abdomen with a pair of basal spots, and at least two 



other yellow bands, or pairs of spots. 



51 (56). At least two abdominal bands entire. 



52 (55). Bands only slightly emarginate (nicked in the middle). 



53 (54). Third joint of the antennae darkened above; scutellum 



dark haired ; frons with a black spot. 

 1533. Syrphus cinctellus, TAX. 

 Gibside, 1 $, 21-8-96; Hesleden, 1 $, 9 ?, August, 

 1898-99; Shipley, 1 ?, 17-7-00; Shull, 1 $, 1 $, 

 5-9-00, 1 $, 7-7-02. The three males differ 

 peculiarly in the shape of the abdomen. In the 

 Gibside male the sides are parallel, and the 

 abdomen is widest at the base. In the Shull male 

 it is somewhat oval, being broadest at the third 

 segment ; while in the Hesleden male it is strongly 

 club-shaped, being unusually narrow at the first 

 and second segments and fore part of the third, 

 and almost doubling its width rather suddenly at the 

 hind part of the third segment. It proves, as Mr. 

 Verrall observes, how unreliable as a character is 

 the shape of the abdomen. 



54 (53). Third joint of the antennae, frons, and scutellar hairs 



all yellow. 



1534. Syrphus cinctus, Fin. 

 Bishop Auckland, 1 $, 21-6-01, 1 ?, 3-7-01. 



55 (52). Bands deeply emarginate. 



1535. Syrphus auric ollis, Mg. 

 Bishop Auckland, 1 $, 26-7-97. 



56 (51). Abdominal bands all broken in the middle. 



57 (64). Antennae at least partly orange. 



58 (61). Antennae with the third joint all, or almost all, orange; 



scutellum pale haired. 



59 (60). Abdominal spots not reaching the side margins. 



(1536. eicchromus, Kow.) 



