A short wander down the Greensand way path produced more Eristalis arbustorum than pertinax, somewhat to my surprise. I have seen a few of the rather dark females at Dene Park, and today I saw both males and females, so it was interesting to try to look at the details a bit more closely.
This is a close-up of the stigma on the wing, slightly blurred out towards or even beyond the junction of the Sc vein with the wing margin, as in the key.
These two photos are perhaps a slightly better view of the tergites pattern, showing how the dark patch on tergite two doesn't widen at the rear to block off the continuity of the yellow between two and three.
This is obviously a male, generally the more brightly coloured of the two sexes in this species I think. The antennae are sufficiently dark to fit the description of the species, although they may look lighter from different angles. Note also the overall clarity of the wings - apart from the stigma of course. Eristalis pertinax does I think have a bit of a wing cloud by comparison, another characteristic allowing me to separate out arbustorum from the pertinax I commonly see around Dene Park more easily.
Another feature that you can start to see is the rather nice white woolly look to the face. The lack of the face stripe is fairly characteristic of arbustorum within the genus, although wear does sometimes remove enough wool to produce a slight face stripe.
The picture below gives some idea of the "pied" nature of the legs, ivory on the tibiae and dark on the mid and fore femora and tarsi. Its not so obvious on the hind tarsus that the limb is dark on the apical half, but it is. I do think however that you can see the swollen nature of the substantial basal section of the hind tarsus below the tibia - if I've got all the sections of the limb correct! The dark fore tarsi of arbustorum contrast with the completely yellow tarsi of pertinax.
It is interesting to note their silvery hairs all around their bodies, on the dark parts of the legs, and on the eyes.
On the other hand this is one of the darker females, most obvious first from their silvery tergite bands, then from the woolly white faces. Again note the "pied" look of the mid and fore legs, and the blurred stigma on both sexes! The other feature I think I am seeing is the white tufts of hair along the side of the thorax, again on both sexes, but I've not seen any reference to this in the books.
The next photo shows the lighter basal half of the rear tibia and the darker apical half, leading onto the obviously swollen metatarsus.
In the next photo you can just see the long hairs on the arista of the far antenna - this is one of my rather less bad pictures. The bicolouring of the hind tibia and the swollen meta-tarsus is, I think, convinging.
This is now some pictures of a male again, the first with a rather nice view of the woolly face and the trident structure part of the way up on the front of the pharynx:
This one is a great shot of the bicoloured rear tibia and the very definitely swollen metatarsus:
This is a fairly good photo of what in bees I think are called the tegulae, the joints that move the wings. In this species of Eristalis, the tegulae are noticeably black from the top, particularly with respect to the other features of the body. From the front they look as if they have a silvery pad on their front surface, as seen in the photo two above.
This is a close-up of the stigma on the wing, slightly blurred out towards or even beyond the junction of the Sc vein with the wing margin, as in the key.
These two photos are perhaps a slightly better view of the tergites pattern, showing how the dark patch on tergite two doesn't widen at the rear to block off the continuity of the yellow between two and three.
This is obviously a male, generally the more brightly coloured of the two sexes in this species I think. The antennae are sufficiently dark to fit the description of the species, although they may look lighter from different angles. Note also the overall clarity of the wings - apart from the stigma of course. Eristalis pertinax does I think have a bit of a wing cloud by comparison, another characteristic allowing me to separate out arbustorum from the pertinax I commonly see around Dene Park more easily.
Another feature that you can start to see is the rather nice white woolly look to the face. The lack of the face stripe is fairly characteristic of arbustorum within the genus, although wear does sometimes remove enough wool to produce a slight face stripe.
The picture below gives some idea of the "pied" nature of the legs, ivory on the tibiae and dark on the mid and fore femora and tarsi. Its not so obvious on the hind tarsus that the limb is dark on the apical half, but it is. I do think however that you can see the swollen nature of the substantial basal section of the hind tarsus below the tibia - if I've got all the sections of the limb correct! The dark fore tarsi of arbustorum contrast with the completely yellow tarsi of pertinax.
It is interesting to note their silvery hairs all around their bodies, on the dark parts of the legs, and on the eyes.
On the other hand this is one of the darker females, most obvious first from their silvery tergite bands, then from the woolly white faces. Again note the "pied" look of the mid and fore legs, and the blurred stigma on both sexes! The other feature I think I am seeing is the white tufts of hair along the side of the thorax, again on both sexes, but I've not seen any reference to this in the books.
The next photo shows the lighter basal half of the rear tibia and the darker apical half, leading onto the obviously swollen metatarsus.
In the next photo you can just see the long hairs on the arista of the far antenna - this is one of my rather less bad pictures. The bicolouring of the hind tibia and the swollen meta-tarsus is, I think, convinging.
This is now some pictures of a male again, the first with a rather nice view of the woolly face and the trident structure part of the way up on the front of the pharynx:
This one is a great shot of the bicoloured rear tibia and the very definitely swollen metatarsus:
This is a fairly good photo of what in bees I think are called the tegulae, the joints that move the wings. In this species of Eristalis, the tegulae are noticeably black from the top, particularly with respect to the other features of the body. From the front they look as if they have a silvery pad on their front surface, as seen in the photo two above.
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