Canadian Journal of Arthropod Identification

| Abstract | Table of Contents | Introduction | Checklist | Subfamily Key | Haematopota Key | Hybomitra Key | Atylotus Key | Tabanus Key |
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The present contribution is an illustrated key to the Canadian Tabaninae east of the Rocky Mountains and is the final part for the eastern Canadian species of Tabanidae following the initial article (Thomas & Marshall 2009) on the subfamilies Chrysopsinae and Pangoniinae that also includes a general introduction and characterization of the family.

These keys are to females only as male Tabaninae are not commonly encountered, except that males of Atylotus spp. are collected as often as females; although neither sex, of Atylotus spp., is commonly collected. Also, I have not seen males of several of the Tabaninae species. Males are keyed in Teskey (1990).

Distribution maps herein are based on the maps in Teskey (1990), with the addition of post-1990 records from the University of Guelph Insect Collection (Department of Environmental Biology; DEBU), and from the author’s personal collection (AWT).

When this project (Tabanidae of Canada, east of the Rocky Mountains) was started, Teskey’s (1990) ``The Horse Flies and Deer Flies of Canada and Alaska`` was out of print and not readily available. However after CJAI published Part 1 and after much of the current MS had been written, The Entomological Society of Canada made Teskey (1990) available online:

The current work supplements Teskey (1990) with updated distribution maps and colour photos of all species east of the Rockies, including paratypes of Hybomitra agora Teskey, Hybomitra enigmatica Teskey, Atylotus calcar Teskey, Atylotus hyalicosta Teskey, Atylotus palus Teskey, Atylotus sphagnicolus Teskey, and Atylotus woodi Pechuman. These photos will make for simpler and more accurate identification when used in conjunction with the current keys or Teskey’s (1990) keys.

For the beginner, good quality specimens, complete with antennae and palpi, are needed for identification. Because of the inevitable variation within species a series of specimens, from the same locality and capture date, are more useful than a single specimen for correct identification.
The following brief comments are not meant as a criticism of Teskey (1990) but simply to document differences between this current project and Teskey (1990) and also to correct some of the errors/inconsistencies in Teskey (1990).

I am rejecting Haematopota champlaini (Philip) as a Canadian species (see Haematopota page).

Teskey (1990) failed to comment on the strange distribution of Hybomitra frontalis (Walker) in Atlantic Canada.
Where found in Canada (transcontinental) it is usually abundant and a major pest. Thus its virtual absence from inland areas of Newfoundland & Labrador and the rest of Atlantic Canada is not readily accounted for. It is a common pestiferous species in the Atlantic salt-marshes of New Brunswick. The distribution of H. frontalis mirrors that of Chrysops furcatus Walker, a species with a continuous distribution from British Columbia to eastern Ontario, but absent further east until it becomes abundant on the same salt-marshes . McAlpine (1961) discounted the possibility that these Atlantic coast populations of Hybomitra (T. frontalis Walker, T. incisus Walker, T. septentrionalis Loew, T. labradorensis (Enderlain)) were anything other than morphs of the widely distributed inland species and suggested that they are all from a single interbreeding population. The large gap between the coastal population and the inland population negates any likelihood of interbreeding.

Hybomitra liorhina (Philip) can be exceedingly abundant on the Tantramar Marshes of extreme SE New Brunswick in early August as opposed to “apparently not very abundant at any locality, collections of only one or two specimens being the rule” (Teskey 1990, p. 213).

I am treating Hybomitra nuda (McDunnough) as a species and not as a subspecies of Hybomitra nitidifrons (Szilady); see Philip and Lane 1984.

The distribution of Hybomitra opaca (Coquillett) is uncertain. Teskey (1990) states (p. 225) “Canadian records for this species are only from Alberta” whereas his map on the same page shows a distribution dot in Saskatchewan. Burger (1995) lists it from Alberta and Saskatchewan.

A 5th Canadian specimen of Atylotus intermedius (Walker) is now known from Ontario, in the DEBU collection. Teskey reported only 4 other Canadian specimens of this incredibly rare species from Ontario.

Atylotus ohioensis (Hine) is confirmed as a Canadian species from specimens in the DEBU collection. Teskey predicted (p. 271) its occurrence in Ontario and Burger (1995) included southern Ontario in the distribution.

Teskey (p. 325) is inconsistent regarding the distribution of Tabanus novaescotiae Macquart in the Maritimes. On page 325 he states “Two collections have been made in the Maritime Provinces” whereas his map (p. 234) shows dots for 9 localities. Similarly for Tabanus catenatus Walker on page 308 he states “… with two collections in the Maritime Provinces” whereas his map (p. 307) shows dots for 4 localities.

Tabanus sackeni Williston is now known from 23 specimens in the DEBU collection with a range extension further north than extreme SW Ontario. Teskey listed only 2 Canadian specimens.

A specimen of Tabanus americanus Forster in the DEBU collection from eastern Ontario (Ottawa River) extends this species range in Canada from extreme SW Ontario.

Tabanus calens Linnaeus is now known from specimens in the DEBU collection from eastern Lake Superior; only in extreme SW Ontario in Teskey 1990.

Tabanus fairchildi Stone has been found to be widespread and relatively common is SW New Brunswick. Teskey recorded it from only 3 localities in Ontario and mentioned a single record from Quebec.

Tabanus limbatinevris Macquart is now known to occur further east than reported in Teskey, with 29 specimens in the DEBU collection vs. “known in Canada only from a few specimens … collected in Essex, Kent, and Lambton counties” (Teskey 1990, p. 316).

Under Remarks for Tabanus marginalis Fabricius (p. 319) Teskey states “Adults of  T. marginalis are not frequently collected”, whereas his map (p. 320) shows a large number of collection sites. In New Brunswick this species is widely distributed in the south and is frequently collected.

Tabanus nigripes Wiedemann is now known from as far west as north of eastern Lake Superior (DEBU collection). Previously only as far west as Georgian Bay.

A specimen of Tabanus subniger Coquillett in the DEBU collection from Oakville, Ont. (10 June 1978) adds to the single record in Teskey from 1932.

Tabanus sulcifrons Macquart is now known from a further 8 locations in SW Ontario other than those in the Niagara Peninsula reported in Teskey. Specimens in the DEBU collection from 12 locations.

In Teskey’s key that separates females of Tabanus sulcifrons from T. limbatinevris (p. 285) some of the text is reversed. In T. sulcifrons the cell is rarely closed (not closed and petiolate as stated) whereas in T. limbatinevris the cell is closed and often petiolate (not rarely closed as stated).

Tabanus trimaculatus Palisot de Beauvois is now known from a further 4 locations in SW Ontario (in the DEBU collection). Teskey reported 1 known Canadian specimen from Guelph, Ont.