key

 -   Subfamilies
 -   Stenopogoninae
      Dioctria
 -   atricapilla
 -   bicincta
 -   cothurnata
 -   flavipennis
 -   harcyniae
 -   humeralis
 -   hyalipennis
 -   lateralis
 -   linearis
 -   longicornis
 -   oelandica
 -   rufipes
 -   rufithorax
 -   sudetica

  contents & layout
  & copyright:
  Fritz Geller-Grimm
  Imprint

 
Identification key to the Dioctria-species

back to the key to Stenopogoninae

Some authors place the genus Dioctria in the questionable subfamily Dioctriinae. A well-established concept for this subfamily is still not presented, however, and therefore it will here be placed within the Stenopogoninae.
The genus is restricted to the Holarctic region and 13 species are known from Germany. A taxonomic revision is needed and especially so for some species-pairs, e.g. D. baumhaueri and D. hyalipennis or D. gracilis and D. bicincta, which are currently synonymised. It is quite possible that additional species will be found in the future.
A table for comparison of taxa is provided on this CD-ROM.

1 a.	Stripes of pale tomentum on pleura restricted to dorsal part of anepisternum (mesopleuron) (meron and metepisternum here not considered) [Fig. 1], [Fig. 2] (marked in red) . . . . . . . . . . . . to 2

1 b.	Stripes of pale tomentum on pleura well-developed and complete or only interrupted dorsally [Fig. 3], [Fig. 4] (marked in red) . . . . . . . . . . . . to 3

2 a.	Postpronotal lobe (humeral callus) and postalar callus distinctly red [Fig. 5]; facial knob below antennal base lacking; face beard (mystax) in males black [Fig. 6]; average length: 8-10 mm . . . . . . . . . . . . Dioctria rufithorax Loew, 1853

2 b.	Postpronotal lobe (humeral callus) and postalar callus usually black or only dark brown [Fig. 7]; facial knob below antennal base well-developed; face beard (mystax) in males yellow [Fig. 8]; average length: 12-14 mm . . . . . . . . . . . . Dioctria cothurnata Meigen, 1820

3 a.	Stripes of pale tomentum on pleura dorsally interrupted, lacking on anepisternum [Fig. 5], [Fig. 6] (marked in red) . . . . . . . . . . . . to 4

3 b.	Stripe of pale tomentum on pleura complete (forming an inverse "U"), anepisternum tomentose dorsally [Fig. 7], [Fig. 8] (marked in red) . . . . . . . . . . . . to 5

4 a.	Coxae yellow [Fig. 5]; hind femora predominantly yellow [Fig. 6] . . . . . . . . . . . . Dioctria lateralis Meigen, 1804

4 b.	Coxae black [Fig. 7]; hind femora predominantly black [Fig. 8] . . . . . . . . . . . . Dioctria longicornis Meigen, 1820

5 a.	Stripe of pale tomentum on pleura complete, with an additional ventral stripe above middle coxa [Fig. 5] (marked in red) . . . . . . . . . . . . Dioctria hyalipennis (Fabricius, 1794)

5 b.	Without an additional ventral stripe above middle coxa [Fig. 7] (marked in red) . . . . . . . . . . . . to 6

6 a.	Tergites partly red (marks or stripes), obvious in dorsal view [Fig. 5], [Fig. 6] . . . . . . . . . . . . to 7

6 b.	Tergites entirely black (last tergites sometimes brownish or sides paler in harcyniae and rufipes) [Fig. 7], [Fig. 8] . . . . . . . . . . . . to 9

7 a.	Postpronotal lobe (humeral callus) and notopleuron red [Fig. 5], [Fig. 6] . . . . . . . . . . . . Dioctria humeralis Zeller, 1840

7 b.	Postpronotal lobe (humeral callus) and notopleuron black, seldom pale [Fig. 7], [Fig. 8] . . . . . . . . . . . . to 8

8 a.	Tomentum on scutum well-developed, forming distinct stripes [Fig. 5], [Fig. 6] . . . . . . . . . . . . Dioctria linearis (Fabricius, 1787)

8 b.	Scutum more or less shiny (atomentose) [Fig. 7], [Fig. 8] . . . . . . . . . . . . Dioctria bicincta Meigen, 1820

9 a.	Legs entirely black, at most knees pale [Fig. 5], [Fig. 6] . . . . . . . . . . . . to 10

9 b.	Legs partly yellow or red [Fig. 7], [Fig. 8] . . . . . . . . . . . . to 11

10 a.

Frons at eye margin with curved, black, long hairs (proclinate orbital hairs) [Fig. 5]; scutum more or less shiny (atomentose) [Fig. 6] . . . . . . . . . . . . Dioctria harcyniae Loew, 1844

10 b.

Frons at eye margin with only short, yellow hairs (proclinate orbital hairs) [Fig. 7]; scutum with distinct tomentose stripes [Fig. 8] . . . . . . . . . . . . Dioctria atricapilla Meigen, 1804

11 a.

Face with a vertical, shiny stripe medially [Fig. 5]; wing distinctly brownish [Fig. 6] . . . . . . . . . . . . Dioctria oelandica (Linnaeus, 1758)

11 b.

Face entirely tomentose, without such a shiny stripe [Fig. 7]; wing not darkened [Fig. 8] . . . . . . . . . . . . to 12

12 a.

Arista nearly as long or somewhat longer than pedicel (2nd antennal segment) [Fig. 5] . . . . . . . . . . . . Dioctria flavipennis Meigen, 1820

12 b.

Arista shorter than pedicel (2nd antennal segment) [Fig. 7] . . . . . . . . . . . . to 13

13 a.

Top of back of head with yellow or brown hairs (occipital hairs) [Fig. 5]; palpi with yellow hairs [Fig. 6] . . . . . . . . . . . . Dioctria rufipes (De Geer, 1776)

13 b.

Top of back of head with black hairs (occipital hairs) [Fig. 7]; palpi with black hairs [Fig. 8] . . . . . . . . . . . . Dioctria sudetica Duda, 1940