Journal archives for February 2022

04 February, 2022

Key to the Syrphus of North America

Here is an attempt at a key to the Genus Syrphus in North America. It is not always possible to identify to species from photos in this genus: many keys (including Vockeroth 1983, and van Veen (Europe)) start with features like the distribution of microtrichia on the wing membrane, and make heavy use of the colour of bristles on the knees or spicules under the middle basitarsus - so they are not exactly primed for photo ID! Hopefully the arrangement of this key makes the genus a little more accessible to photo ID, and crucially exposes some information on those rare species that create nagging doubts in the back of the mind. Many observations will still not be identifiable to species however.

One of the difficulties of identifying in this Genus is being sure of the genus in the first place! There are included some pointers to help with that. I have also included a slide of information on European Syrphus because there is significant overlap.

I have not illustrated the key itself (although there are images on some of the introductory slides), however the names of species at the points they key out are hyperlinked to iNat observations. Bear in mind that for many species, there are no iNat observations however: it is my hope that this key might help to dig them out! Many species are sexually dimorphic, so when comparing images, be sure to compare with the correct sex.

Please let me know of any errors of fact or clarity.

The species covered are:
attenuatus, currani, intricatus, knabi, opinator, rectus, ribesii, sexmaculatus, sonorensis, torvus, and vitripennis. There are also some comments on dimidiatus Fabricus 1781, dimidiatus Macquart 1834, doesburgi and monoculus.

Posted on 04 February, 2022 00:12 by matthewvosper matthewvosper | 22 comments | Leave a comment