Hoverflies of Northwest Europe

Boek Noordwest Europese Zweefvliegen

The book contains identification keys to virtually all hoverfly species of Northwest Europe and is written in English. Northwest Europe ranges from Great Britain in the west to the German-Polish border in the east, and from the Loire in the south to the north pole in the North. The books of Van der Goot (1981, 'Zweefvliegen van Noordwest Europa, in het bijzonder de Benelux') and Verlinden (1991, Syrphidae in the series Belgische Fauna) are the core of the book. The vast amount of literature since 1981 and the collection at the Zoological Museum Amsterdam have been used to modify and extend keys. New keys have been build for genera that changed markedly the past 20 years. It is published by the KNNV publishing, where it can be ordered.

Addendum to the book

To my dismay, the book contains a number of typing errors. These are, as honest as possible, reported here if they concern the keys and the figures. In addition, new species have been added and revisions have been carried out. I try to follow them and provide guidance how the change the keys in the book here.

Brachyopa.
Doczkal and Dziock (2004) added two species in Volucella 7. These are added in the Brachyopa addendum. This addition is relevant for Europe as a whole. The keys now contain all European Brachyopa.

Brachypalpus
Figure 94. Brachypalpys must be changed to Brachypalpus.

Cheilosia.

* Haarto, Kerrpola and Ståhls (2007, Volucella 8, p. 63) describe Cheilosia naruska as a new species from northern Europe. This species keys out in the impressa-group (p. 63 in my key). There, it would key out to Ch. semifasciata, because the legs are completely black and although the wing base is paler, it is not yellow like Ch. impressa (according to their photo of the male, but they state in the description "wings: yellowish brown tinged at least basally").
The species differs from Ch. semifasciata by the following
- base of tibia deep black, not turning a little brown
- mouth edge not extended, even less than fig. 166-167 (Ch. impressa)
- male: abdomen without silverish spots

The species differs from Ch. impressa by the following:
- "the front coxa being without a hook" (in de diagnosis), repeated in the description as "procoxa without lateral hook".

If I interpret their taxonomical remarks rightly, they state that Ch. fasciata in Finland has the tibia completely black. That is in contrast to Ch. fasciata in the Netherlands and Belgium, which have the base of their tibia yellowish. May be cold winter temperatures cause this difference.

* Bartsch (2005, Natur i Norr 24(2):61-66) found Cheilosia hercyniae in Sweden, a species here fore known from mountainous regions and therefore omitted in the book. It would key out tot Cheilosia pagana. Change item 9 in the pagana-group (p. 59) as follows.

9. a Males and females. Sternites shiny, without dust -> 10
9.b. Females only. Sternites with thin silverish dust; 3rd antennal segment red, as long as wide; Tars 1: first segments pale -> Cheilosia uviformis Becker.

10.a Tars 1: middle segments pale. Male: frons flat, not swollen in profile; 3rd antennal segment 1.5 times as longs as wide. Female: 3rd antennal segment large and red, without furrow. Smaller: 5-8 mm. Holarctic -> Cheilosia pagana Meigen
10.b. Tars 1: middle segments black to brown. Male: frons swollen in profile; 3rd antennal segment as long as wide. Female: 3rd antennal segment red, on anterior side with a distinct furrow. Larger: 8-9mm. Central Europe, Sweden. -> Cheilosia hercyniae

* Cheilosia pallipes is renamed to Cheilosia flavissima. Change 2 on page 57 (pagana-group) to the following to add characteristics.

2.a. Wing: base hyaline, brownish or blackish; face: black. Female: scutellum at least black on front half -> 3
2.b. Wing: base yellow; face partly yellow; Female: scutellum yellow. -> Cheilosia flavissima

* Bartsch (2009b) includes Cheilosia reniformis, only found around Helsinki. It is part of the fraterna-subgroup (p. 77 in the Hoverflies book) in which it neatly fits because the bristles on the hind rim of the scutellum are absent or present (short in the latter case). The drawing of the species in Bartsch (2009b) has a completely black arista, so it would end up near Cheilosia fraterna and Cheilosia bracusi in the Hoverflies-book. I am not able to check Cheilosia reniformis, provisionally let 2.a. refer to i and insert i between item 2 and 3 (on p. 77).

i.a. Large species: 8-13mm; eyes: hairy all over or bare on lower part; tibia 3: pale with black patch or pale with black ring. Female: hairs on scutellum long -> 3
i.b. Small species: 7-8mm. Male: eyes hairy all over and tibia 3 with black ring (as the large Cheilosia bracusi of central Europe). Females: eyes bare on lower part and tibia 3 with black ring; scutellum with extremely short hairs. Finland only -> Cheilosia reniformis

* Bartsch includes Cheilosia flava, which belongs to the canicularis-group in the Hoverflies-book (p.74). It keys out to Cheilosia flavipes.  Change 10.b. and include 11 as follows:

10.b. Tibia 3 yellow -> 11

11.a. Males and females. Tars 1 and 2 mainly black above; frons: hairs black. 7-9mm. Southern Finland. -> Cheilosia alba
11.b. Males only. Tars 1 and 2: at least three basal segments yellow above; frons: pale hairs present among the black. 7-11mm. Central and Northern Europe -> Cheilosia flavipes

Dasysyrphus
Bartsch (2009) includes D. postclaviger and D. nigricornis in his keys. They would key out in the Dasysyrphus-key (p. 86) as follows.

* D. postclaviger causes problems in item 5 because the antennae are yellow, but the spots on the abdomens are constricted like D. friuliensis. Change the  key as follows on p. 87:

5.a. Tergites 3 and 4: spots strongly narrowed to less than 0.5 times their largest width; antennae black, dark-brown or pale -> i
5.b. Tergites 3 and 4: spots hardly narrowed, at most to 0.6 times their largest width; antennae pale -> 6

i.a. Antennae pale; scutellum: hind margin with a black margin, scutellar dorsum predominantly yellow haired; face with pale hairs. 7-11 mm. Northern Europe, mostly  above polar circle. -> Dasysyrphus postclaviger  Stys and Moucha
i.b. Antennae brown to black; scutellum: hind margin yellow, scutellar dorsum predominantly black haired; face predominantly with black hairs. 10-12mm. Northern and central Europe. Dasysyrphus friuliensis Van der Goot.

* Dasysyrphus nigricornis. Bartsch (2009) does not include D. lenensis, thus inclusion of D. nigricornis in the key is somewhat tricky. The addition below is provisionally. The change starts at item 7 (p. 88).

7.a. Scutellar dorsum with predominantly black haired. Male: hairs on the side margin of tergite 2 yellowish (with black ones in hind corner); angle of approximation of eyes acute. Female: dust patches on frons large and (almost) touching, their width in the middle is 1/4th of the distance between lunulae and ocelli or wider -> 8
7.b. Scutellar dorsum predominantly yellow haired. Male hairs on the side margin of tergite 2 black; angle of approximation of eyes blunt or acute. Female: dust patches on frons small, only present around eye margin and when extending into the middle, their width in the middle is less than 1/5th of the distance between lunulae and ocelli -> i

i.a. Males: angle of approximation of eyes more than 90 degree. Female: dust patches on frons small, only present around eye margin, although they extend into the middle, they hardly touch. 5-8mm. Northern and central Europe. -> Dasysyrphus pauxillus Williston
i.b. Male: angle of approximation of eyes less than 90 degree. Female: dust patches extending into the middle forming a band. 5-8mm. Northern Europe above polar circle. -> Dasysyrphus nigricornis Verral

Epistrophe.
On page 93, item 10.a. should refer further to item 11 (instead of 10).
On page 94, fig. 297 and 298, the old name E. similis should be E. obscuripes.

Bartsch (2009) adds two species that are not in my keys, E. olgae and E. annulitarsis. They can be added to the Epistrophe key (p. 91) as follows.

* Epistrophe olgae. This is a siberian species that is present in Finland and the central part of Sweden. It will key out to E. nitidicollis at item 8b. Let item 8b refer to i, change in 8b 'scutellum largely black haired' to 'scutellum with at least onethirdth of hairs black' and remove the part on the frons of the female. Item i becomes:

i.a. Arista black; frons grey dusted only along eye margin, shiny (or nearly so) in the middle. 11-12mm. -> Epistrophe nitidicollis Meigen
i.b. Arista yellow; frons evenly dusted in posterior half, gradually less so towards the lunulae. 9-12mm. Sweden, Finland, Siberia. -> Epistrophe olgae Mutin

* Epistrope annulitarsis. This is a Finnish endem. It is probably best to include it at item 7 (p. 93) as I am not sure about the coverage of microtrichia in the first basal cell. Bartsch states in the Swedish description that the second basal cell is completely covered with microtrichia. I guess the species will key out to item 12 and is internediated between E. obscuripes and E. cryptica (differing from both by the black hairs on the scutellum and the coloration of tars 3). First relabel item 7 in the book to 7*.

7.a. Tars 3: enterily pale or dark, without distinct dark rings on yellow background -> 7*
7.b. Tars 3: background colour pale, with 6 well defined black rings (base and top of metatars and tops of the other tarsal segments; scutellar dorsum mainly black haired; arista black; face yellow; tergite 5 yellow with a black spot in the middle. 11-13mm. Finland. -> Epistrophe annulitarsis (Stackelberg).

Eriozona
Recognition, 2nd line: oestraceus must be oestracea.

Eristalis.
Many names appeared to be female instead of male. The change was implemented in the last stage and failed at several points.

On p. 99, item 3 and 4 remained in wrong order (E. cryptarum also has a yellow metatars 3). Solution: switch them. Renumber 4.a. and 4.b. to 3.a. and 3.b. and vice versa. The new 3.a. refers to 4, the new 4.b. refers to 5.
On p. 100, fig. 322, I used the old name E. pratorum, should be E. similis.
On p. 101, fig. 328, I used the old name E. horticola, should be E. lineata.
(difficult if you use the old names for over 20 years ;-)

Eupeodes.
Eupeodes rufipunctatus occurs in Iceland (Bartsch, 2009). It is separated from all other Eupeodes by its reddish, bad-marked spots, whereas the other species have yellow, well-marked spots.

Microdon
Figure 483 is wrong, it is a copy of figure 482. The figure is not essential in the key.

Neoascia.
On page 145, item 1b should refer further to 5 (instead of 4).

Orthonevra
Figure 532 is wrong and simply a copy of figure 531. It is not essential in the key.

Parasyrphus.
On page 160, item 10a should refer further to 11 (instead of 10).

Parhelophilus.
On p. 161, item 2b should refer to 4 (instead of 5).

Pipiza.
On p. 166, item 9a should refer to 10 (instead of 11).

Platycheirus.
On page 175, item 21.a. refers to 22 (instead of 2).

Nielsen (2004) published new species in the P.ambiguus-group in Volucella 7. These are all added in the Platycheirus addendum. This addition is relevant in montane and boreal areas. Some species only occur in montane areas in Southern Europe.

On p. 182, item 41b, the synonym is P. argentatus Ringdahl.

Bartsch (2009) includes two further species not present in my key, P. urawakensis and P. magadanensis.

* P. magadanensis. This species is close to P. clypeatus. Females are unknown, Bartsch assumes it is close to P. europaeus. Males will readily key out to item 39 (p. 181) and then cause trouble. The solution is probably to change item 39 and add 39*.

39.a. Metatars 1: ventrally with a black marked, narrow pit in the distal part; tars 3 with central 2 segments pale and last 2 segments black; tibia 3 with broad pale top and base; tergites with yellow spots undusted -> 40
39.b. Metatars 1: ventrally with a broad pit in the middle, without much dark coloration; tars 3 black or brownish, little or no contrast between central and last segments; tibia 3 almost completely dark, leaving small pale top and base; tergites with yellow spots undusted or heavily greyish dusted -> 39*

39*.a. Tergites with yellow spots without grey dusting. Larger: 7-9mm. Northern Europa, Siberia, above polar circle. -> Platycheirus magadanensis Mutin
39*.b. Tergites with spots heavily dusted, yellow colour hardly visible. Smal: 5-7mm. Platycheirus hyperboreus Staeger

* P. urawakensis. According to Bartsch (2009), the male of P. urawakensis will readily key out to P. albimanus, item 28 (p. 177). Change Item 28.a to refer to 28* and

28*.a. Tibia 1: the extension at the posterior part of the top triangular, it ends acute; metatars 1: posterior edge gently curved. 7-10mm. -> Platycheirus albimanus Fabricius
28*.b. Tibia 1: the extension at the posterior part of the top almost rectangular, it ends truncate; metatars 1: posterior edge angular at 1/3rd of the top. 6-9mm. Northern Europe and Asia. -> Platycheirus urawakensis (Matsumura)

Psilota.
I used, with their agreement, a prepublication of Smit and Zeegers to include all 3 west palaearctic species. Unfortunately, they switched the names of P. atra and P. anthracina in their official publication, which appeared after my book was published. Please swap the names in my book!!!!
- P.atra becomes P. anthracina
- P. anthracina becomes P.atra

Sphaerophoria.

Item 6 and further is for male specimens only.

Item 8a, p. 203: the second figure reference should be to 710 instead of 712.

Bartsch (2009) discovered two siberian species in Northern Europe, S. pallidula and S. kaa.

S. pallidula. A species close to S. taeniata. Introduce item 10* between 10 and 11 (p. 203), 10.a. now refers to 10*

10*.a. Genitalia: base of toothed lobe without bulge and, seen from the side, the form of the toothed lobe rectangular, sometimes weakly S-shaped by a bend; toothed lobe about as long as hairy lobe; tergite 2: with yellow band (than projection on the toothed lobe or just at the contact zone of both lobes) or with 2 yellow spots -> 11
10*.b. Genitalia: base of toothed lobe with a distinct bulge at the base, the form of the toothed lobe triangular seen from the side; toothed lobe longer than hairy lobe; projection on hairy lobe; tergite 2: always with yellow band. 8-10mm. Northern Europe and Siberia, above polar circle. -> Sphaerophoria pallidula Mutin

S. kaa. A species very close to S. abbreviata and S. fatarum. Change item 13 (p.205) to

13.a. Appendage of hairy lobe viewed from below or above: not contricted at the base, gradually tapering into the tip; toothed lobe less shouldered, rather slender and its width about twice the width of the tooth at its base -> 13*
13.b. Appendage of hairy lobe viewed form below or above: petiolate with a constriction at the base (like an arrow point); toothed lobe distinctly shouldered, its width more than twice the tooth at its base. 7-10mm. Sphaerophoria abbreviata Zettersted

13*.a. Appendage of hairy lobe with a long tapering tip; distinct projection on the base of the hairy lobe. 7-10mm. -> Sphaerophoria fatarum Goeldlin de Tiefenau
13*.b. Appendage of hairy lobe with a short tapering tip; projection at the base of the hairy lobe weak and almost absent. 7-9mm. Northern Europe, Siberia, above polar circle. -> Sphaerophoria kaa Violovitsh

It is best to change item 15 into

15.a. Tergite 2: yellow band; genitalia: toothed lobe not shouldered beneath teeth -> 16
15.b. Tergite 2: two yellow spots, at most touching; genitalia: toothed lobe shouldered  beneath teeth -> 12

Temnostoma.
I got the Russian keys of Krivosheina (thanks Martin), they are translated (thanks Hanneke) and published in the Temnostoma key. The additions are relevant in boreal areas.

Triglyphus.
Figure 772 is a female, while figure 773 is the male.

Xanthogramma.
While writing the book there was dispute over the identity of Xanthogramma pedissiquum. Bartsch (2009, nationalnycklen, part 1) adds X. stackelbergi to the northwest European fauna. The map shows it is found all over Denmark and it is good to look out for the species further south. Change the Xanthogramma-key (p. 224) as follows.

2.a. Femur and tibia 3 pale with dark ring; tergite 2 with broader spots than those on tergites 3 and 4, spots on tergite 2 triangular -> 3
2.b. Femur and tibia 3 completely pale; tergites 2-4 with subequal spots, spots on tergite 2 linear -> Xanthogramma citrofasciatum DeGeer (=Xanthogramma festivum)

3.a. Wing: the dark patch around the stigma extends to two cells below the stigma; view from below: the membrane between the sternites and tergites at each segment yellow in front quarter, black on back threequarters. 10-13mm. -> Xanthogramma pedissiquum Harris
3.b. Wing: the dark patch nearly absent, extends only to the cell just below the stigma; view from below: the membrane between the sternites and tergites completely yellow on segments 3-5. 10-12mm. Northern Europe, Siberia. -> Xanthogramma stackelbergi Violovitsh

 

Last updated 29.12.2009