|Positive ||wallaby1 ||On Jun 23, 2007, wallaby1 from Lincoln
(Zone 8a) wrote:
This fly is harmless, it resembles a drone worker bee hence the name. It is quite large, has no narrow waist, the eyes are typical of a fly and it has no sting!
This can easily be confused with other Eristalis, in particular E. pertinax but also E. arbustorum. With careful observation and research I have found the main differences.
The tibiae of the hind legs on E. tenax are dark, with little or no yellow on the legs. E. pertinax has bicoloured tibiae on the hind legs.
E. tenax has a more distinct, broader dark stripe down the centre of the face than E. pertinax, while E. arbustorum has no stripe or very little.
E. tenax has a near cylindrical abdomen, the female is variable and sometimes has little or no orange pattern. E. pertinax has a more triangular, tapering abdomen.
E. arbustorum is smaller than the other two, I have had all three and the size difference is very noticeable. E. arbustorum also has distinct white bands across the abdomen.
The larvae of E. tenax are laid in organically polluted water, using the tail as a breathing tube. When they are ready to pupate they will often crawl into a shed or building.
Reference sites used are as follows