EEISTALIS. 159 



28. Eyes with two distinct bands of dense, 



darker-coloured pubescence tenax, L., p. 173. 



Eyes without any such bands 24. 



24. Wiujrs with a large, conspicuous brown [p. 1G7. 



spot in middle inaculijiennis, de Meij., 



Wings grey ; abdomen w^ith greenish sub- 

 metallic spots ; eyes bare tiit/er, Wied., p. 163. 



AVings grey ; abdomen black, with trans- 

 verse yellowish-grey bands ; eyes with 

 obvious greyish pubescence on lower 

 half ; almost a " furry '' species orientalis, Wied., p. 170, 



E. transpositus. Walk., pallineuris, Macq. (p. 160), and cognatus, 

 Wied. (p. 175), are not included in the above table owing to no 

 int'oruiation being available as regards the antennae. The l ype of 

 transpositus is probably lost. The first two species have the thorax 

 metallic, and transpositus possesses, in addition, a large dark spot 

 in the middle of the wing; this spot is absent in paUhieuris. 

 E. cof/natus, Wied., falls near tenax. E. mult i farms, Walk., is alao 

 not included in the table as the hind femora are rather con- 

 spicuously incnissated ; see remarks on p. 194. 



The several attempts wliich liave been made to subdivide Eristalis 

 on account of the unwieldy number of its species cannot be 

 considered successful ; as whether the markings of the eyes or 

 those of tlie tiiorax be adopted as characters on which to effect 

 the subdivision, by either method groups of species are created 

 which are by no means homogeneous. iSucli groups in any case 

 must be regarded at most as subgenera. If based on the eye- 

 markings, ^7?«s the separation of species with plumose arista from 

 those having this organ bare or nearly so, tiiese subgenera would 

 be as lollow.s : — 



Arista distinctly plumose on at least basal half .... Eristalis, 

 Arista bare or slightly pubescent. 



Eyes with longitudinal dark stripes * Eristalodes. 



Eyes with spots or irregular markings. 



Eyes contiguous m S Lathiirophthabnns. 



Eyes rather widely separated i7i r' Eristalinns. 



E^'es unicolorous, unmarked Eristalontijia. 



In the first place, since the species tenax, L., tlie universally 

 accepted type of the genu.s, would under the above arrangement 

 fall in the subgeiuis Eristalomi/ia, this latter name would have to be 

 replaced by Eristalis, s. sir., whicli would necessitate i-enaming the 

 subgeiniH with species possessing a plumose arista. Verrall abso- 

 lutely refused to place the species tenax, L., in any other genus 

 except Eristalis : but if the above subgenera were to bo 



* Stripes are iilwajs longitudinal, to wnuteviT part, of the body the terra niny 

 be applied ; if tnuisverso they an; called /w//f/s (or transverse stripes). So far 

 as n\j own writing.-* go, ilie.so ttTtns aro never used in any contrary sense. 

 Measurements of the extent of contiguity of the eyes, -ire made from tlie extreme 

 vertex to the extreme anterior pr.>.jecting margin of tlio frons, which overhangs 

 the actual base of the antennje. Measurements of tlie width of tlic frons in the 

 2 are made on a line running through the base of the antenna;. In all such 

 cases my measurements have been judged by the eye aloue. 



