82 [April, 



Bridges in Sussex which may belong here. Some specimens 

 taken in the New Forest in 1904 by Mr. C. G-. Lamb would 

 answer well to D. haUeralis Lw., but it is curious that I can find 

 no representatives of that species in Kowarz's collection, and 

 I suspect that he subsequently considered it not distinct from 

 D. nigricans, as he had a collection of the genus Diaphorus 

 evidently prepared for a monograph. Mr. C. Gr. Lamb's 

 specimens seem distinctly smaller than my D. nigricans. 

 4. D. Winthemi Meig. : this species ought to have been in italics in 

 the first edition of my List instead of D. nigricans, as I find 

 my only authority for introducing it was founded on a female 

 with yellow halteres, caught at Plashet Wood in Sussex on 

 July 3rd, 1868, which was named D. Winthemi by Loew. 

 Two doubts arise ; one as to whether Loew knew the females 

 of these species correctly, and the other as to whether the 

 specimens caught at Three Bridges as mentioned under B. 

 nigricans belong to this. The species must remain doubtful 

 as British at present, though it is most likely to occur. 



16. AEG YE A Mcq. 



1 (2) Scutellum pubescent on disc ; thorax not silvery ; abdomen yellow at 



sides 1. diaphana Fabr. 



2 (1) Scutellum bare, except for marginal bristles. 



3 (8) Thorax silvery. 



4 (5) Face black 2. leucocephala Meig. 



5 (4) Face silvery. 



6 (^) Arista as long as, or longer than, antennae ; antennaj scarcely longer than 



head 3. argyria Meig. 



7 (6) Arista shorter than antennae ; antennae considerably longer than head... 



4. argentina Meig. 



8 (3) Thorax not (or scarcely) silvery. 



9 (12) Basal joint of hind tarsi longer than next joint; face black. 



10 (11) Abdomen silvery ; basal joint of hind tarsi bearing some rather long 



hairs 5. conjinis Zett. 



11 (10) Abdomen scarcely at all silvery ; basal joint of hind tarsi without any 



special pubescence 6. atriceps Lw. 



12 (9) Basal joint of hind tarsi not longer than the next joint ; face white ; hind 



tibiae conspicuously bristly above 7. elongata Zett. 



A very natural genus, in which the males of nearly all the species are 

 more or less covered with a beautiful silvery gloss. 



1. A. diaphana Fabr. : the lai'gest British species, and very easily 

 distinguished by its pubescent scutellum. Fairly common 

 over all Britain. 



