196 



INSECTS OF SAMOA. 



VOLUCELLINAE. 



8. Volucella obesa Fabr.* 

 Upolu, 5 (^(^, 9 o?, 15.iii-vi., xii.1925. Tutuila, 1 ^, 18.iv.l924 (Bryan). 



Eristalinae. 



9. Dissoptera maritima sp. n. 



Four males of this peculiar fly included in the present collection present 

 important differences from D. unicolor Bezzi, to which, owing to its general 

 dark coloration, the species would appear to be related. The antennae are 

 black, not reddish, and the arista, which is scarcely longer than the entire 

 antenna, is very strongly thickened on its basal half or two-thirds. The 

 yellowish scaly tomentum is not at all apparent, although some short yellowish 

 hair is present beneath the longer black vestiture. The halteres are yellowish, 

 and the male genitalia slightly visible from above. There are some long pale 

 hairs on the hind femora, especially about the tips, as well as the denser, stiff, 

 semi-appressed black bristle-like hairs. The wing-veins are brownish, and the 

 costa ends approximately at the tip of wing. Bezzi states that the eyes of 

 D. unicolor are unicolorous, but in all four specimens before me I can observe 

 well-defined, small, point-like spots or reflections, suggesting the appearance 

 afforded by certain females of Lathy rophthalmus. 



^. Eyes bare, separated widely, as described for Z). unicolor, narrowest in 

 profile on lower half ; distance between eyes at lower part of front but slightly 



* This species frequented earth closets, and was observed to deposit its eggs on the under 

 side of the seat. — P. A. Buxton. 



Possibly owing to the agency of old-time sailing ships, to which it may have been attracted 

 by odours, Volucella obesa has a wide distribution in the tropics, where it occurs in both hemi- 

 spheres. As shown by the series of specimens in the British Museum, apart from Samoa the fly 

 is found at any rate in Mexico, Central and South America, the West Indies, the Sandwich Is., 

 Tahiti, Rodriguez I., Mauritius, the Seychelles Is., Madagascar and N. Nigeria (the National 

 Collection includes a solitary specimen from Kano). On the Lower Amazons, Brazil, thirty-odd 

 years ago, it was " very common everywhere," and its association with privies was also noted. 

 " Like the Bee {Chrysantheda nitida), which it closely resembles when on the wing, this fly is the 

 victim of an overpowering curiosity, and remains poised in the air in front of one in a way that 

 is perfectly irritating. It seems to be an exceedingly stupid fly, and when caught in the net its 

 movements at once become dull and sluggish " {cf. Austen, Proc. Zool. Soc. Lond. 1896, p. 776). 

 — B. B. Austen. 



