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Provisional key to the Central European species of the genus Choerades Walker

Fritz GELLER-GRIMM & M. J. SMART

(1998)

[not published]

Choerades marginata, female

Introduction

The following collections were checked: Coll. Geller-Grimm, Coll. Hauser, Coll. Hradsky, Coll. Stuke and Coll. Dressler. No types were examined. Unfortunately only males are known from some species and C. mouchai Hradsky, 1985 has not yet been included in the key. Moucha & Hradsky (1955) lay the foundations for this work. Miksch et al. (1993) described a variation of C. marginata, that specimens has since been determined by Mr. Hradsky (1997) as C. marginata s.str. Mr. Wolff has drawn attention to some new characters, which are included.


1 Legs red, tarsi black. . . . . . . . . . rufipes (Fallén, 1814)
- Legs black. . . . . . . . . . 2
2 Tergites black. . . . . . . . . . 3
- Tergites black with red markings. . . . . . . . . . 9
3 Middle tergites (3 to 6) without laterodiscal setae; postpronotal lobe and pleuron scarely tomentosed; thorax densely hairy (like a hairy bee); wings darker at the tip and with a transverse spot at the middle along the veins; 1st antennal segment about 4 times as long as segment 2. . . . . . . . . . fuliginosa (Panzer, [1798])
- Setae present on the upper surface at the lateral corners of each middle tergite; postpronotal lobe (= humerus) and pleuron with distinct tomentum. . . . . . . . . . 4
4 1st antennal segment 3.4 - 4 times as long as segment 2; face of males with white hair above the knob [rarely with yellow hair], females with yellow hair; anepisternum with greyish-brown tomentum and with yellow and black hairs, which cover it loosely; base of costa of the males with white hair dorsally and yellow on the ventral surface, females with predominantly black hairs (in contrast with C. marginata, which has yellow hairs on the ventral side of the base the costa); tergites scantily covered with hair, exclusive of the hind corners, which have yellow hair (tergites have the appearance of being bare), the hair is directed from the front corners to the hind middle of each tergite; the hind tomentosed spots occupy 3/5 of the width (only one third in C. marginata); specimens usually smaller thanC. marginata. . . . . . . . . . femorata (Meigen, 1804) sensu Moucha & Hradsky (1955) [= marginata sensu Miksch et al. (1993)]
- 1st antennal segment at most 3 times as long as segment 2. . . . . . . . . . 5
5 [Only males are known to me] Tergites 1 - 3 with white hair only; 1st antennal segment 2.5 - 3 times as long as segment 2; face with white hair above the knob; anepisternum with greyish-brown tomentum; base of costa with white hair. . . . . . . . . . dioctriaeformis (Meigen, 1820)
- At most the 1st 2 tergites with white hair only. . . . . . . . . . 6
6 Anepisternum with greyish-brown tomentum and with rather sparse yellow and black hairs all over. . . . . . . . . . 7
- Anepisternum with yellow tomentum and with dense yellow hair in the middle. . . . . . . . . . 8
7 Tergites of the males with yellow hair at the sides, black adpressed hair on the middle and white hair along the hind margins, the hair is directed in straight line from the front to the hind margin of each tergite; tergites of females are hairy like C. fimbriata, but the hind tomentosed spots occupy only one third of the width and the yellow hair is more thick; 1st antennal segment 1.8 - 2.1 times as long as segment 2 in males and 3 times longer in females; face with yellow hair above the hump; base of costa dorsally white, ventrally yellow in males (like C. femorata) and dorsally black, ventrally with dense yellow hair in females; specimens usually bigger than C. femorata. . . . . . . . . . marginata (Linnaeus, 1758) sensu Moucha & Hradsky (1955) [= marginata var. sensu Miksch et al. (1993)]
- [Only males are known to me] Tergites with only yellow hair, the dense hair is directed from the front corners to the middle and thence to the hind corners of each tergite (like C. fulva); 1st antennal segment 1.6 times as long as segment 2; face with yellow hair above the knob, beard yellow and dense, the long hair below the base of antenna angled downwards; base of costa with yellow hair, except for a few black hairs dorsally. . . . . . . . . . castellanii (Hradsky, 1962) [= fulva sensu Moucha & Hradsky (1955)]
8 Only the 1st tergite with white hair in males, the following tergites with black hair on the front half and dense yellow hair behind, the hair is directed from the front corners to the middle and thence to the hind corners of each tergite; tergites of females with only very long and dense yellow hair (specimens of this species often been determined as C. fulva); mesonotum with dense white hair in front of the scutellum in males, dense yellow hair in females; face with yellow hair above the hump; 1st antennal segment 1.4 - 2.0 times as long as segment 2; base of costa with yellow hair, ventrally also some blackish hair. . . . . . . . . . fimbriata (Meigen, 1820)
- [Only males are known to us] 1st tergite and also most the 2nd with white hair, the other tergites with dense yellow hair (somewhat shorter in the front half) and black hair only in the middle of each tergite, the hair is directed from the front corners to the middle and thence to the hind corners; scutellum and mesonotum in front of the scutellum with dense white hair; face with pale yellow hair above the knob; 1st antennal segment 1.4 times as long as segment 2; base of costa with yellow hair, ventrally also some black hair. . . . . . . . . . fulva (Meigen, 1804)
9 1st sternite shiny; scutellar setae usually black; 2nd tergite usually black. . . . . . . . . . gilva (Linnaeus, 1758)
- 1st sternite with whitish tomentum; scutellar setae usually yellow; 2nd tergite usually with red spots. . . . . . . . . . ignea (Meigen, 1820)
     
     
     
     

Remarks

The measurements of the antennal segments are not executed with the new instruction, made by Mr. Smart [compare the instruction now]. To clarify the femorata-problem, Mr. Smart will examine the types of Meigen at Paris this year.

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Adresses

Fritz GELLER-GRIMM, Spielmannstr. 20, D-65934 Frankfurt a.M., Germany
Malcolm J. SMART, Southcliffe, Pattingham Road, Wolverhampton WV6 7HD, England




Last saved Oct. 19 1998
© F. Geller-Grimm