262 MR. R, SHELFORD ON MIMETIC INSECTS AND | Nov. 4, 
curved submedian vein in the wing of the fly represents the 
junction between the fore and hind wings of the bee, and the areo- 
let of the hind-wing of the bee also finds its parallel in the 
alula of the fly. The halteres are quite concealed amongst the 
hairs on the sides of the thorax, I have only seen one solitary 
specimen of this fly (Kuching, Feb. 1899), and have nothing to 
record of its habits beyond stating that both on the wing and at 
vest it was exceedingly difficult to distinguish from the common 
A. latipes (compare figs. 1 & 2, Plate XXIT.). 
[ It is possible that the fly is constantly mistaken for a Xylocopid, 
and that it is not nearly so rare as it appears to be, The genus 
is widespread, and Mr, G. A, K. Marshall has sent me an equally 
beautiful example from Mashonaland, In this case the insect 
Is unique (it has been recently described as Hyperechia marshalli 
(Austen)), but Mr. Marshall’s notes clearly indicate the reason of its 
rarity. It must be remembered also that the extreme perfection 
of the resemblance is aided by the rapid flight and alertness of the 
fly. Hzyperechia belongs to the same family and subfamily as the 
species last described, and here, too, the Miillerian interpretation 
must be taken into account. ia fact Mr, Roland Trimen, to 
whom I showed the African specimen, expressed the opinion, from 
his experience of its allies, that it is a far more formidable insect 
than its model. The strengthening and curvature of the sub- 
median vein in the fly’s wing, which apparently represents the 
junction between the bee’s fore and hind wings, is an instance of 
the attainment of a detail in the resemblance by a very slight 
alteration of form ; for the vein in the last-described species of fly 
pursues nearly the same curved direction, although the line of 
junction of the wings of its model is nearly straight. In both 
species of fly there is a slight break in the even contour of the 
margin at the point where this vein reaches it, which is very 
suggestive of a junction between fore and hind wings, while the 
eurve of the margin is changed on either side of the break in such 
& manner as further to promote the resemblance.—E. B, P.] 
Mimic. JJilesia vespoides (Wlk.). Plate XXII. fig. 14. 
Model. Vespa cincta (Fab.), Plate XXII. fig, 13. 
The large wasp, black with a broad red band on the second 
abdominal segment, is closely mimicked by an equally large fly 
with the distal half of the second segment and the proximal half 
of the third segment coloured red. This red band, though 
actually occupying a different position from that of the wasp, is 
separated from the thorax by a black interspace nearly equal in 
breadth to the wasp’s first abdominal segment, which is also black. 
The wings are similarly coloured in both species (compare figs. 13 
& 14, Plate XXII), 
Mimic, Midas, n.sp, (Fam. Midaide.) Plate XXII. fig. 12. 
Model. Macromeris violacea (Lep.). Plate XXII. fig. 11, 
Macromeris violacea, a dark blue fossorial wasp, with dark blue 
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