Chelonus gravenhorstii
author(Nees, 1816)
synonymsChelonus eurytheca Wesmael, 1838; Chelonus maculator Dahlbom, 1833; Chelonus tricolor Tobias, 1976
body
shapeBody 3.7 - 4.0 mm long [P6], 3.5-4.0 mm [T14]. 3.5 - 5 mm [Te1]. ♀ 3.1 - 3.8, ♂ 3.5 - 3.8 [T5]
colorblack [N].
head
shapeHead in dorsal view (Fig. 1) transverse, twice as broad as long, eye twice as long as temple, latter receded or rounded. Ocelli almost round, OOL : OD : POL as 10 :4 :8 . Eye in lateral view 2.1 times as high as wide, temple just wider than eye (Fig. 2, see arrows). Malar space one-fifth longer than basal width of mandible. Face 1.7 times as wide as high, inner margin of eyes parallel [P6]. Head almost rectilinearly narrowed behind eyes, wider than mesonotum, twice as wide as long. Temples slightly shorter than or equal to the transverse diameter of the eye. Base of ocellar triangle larger than OOL plus an ocellus diameter. POL is twice the diameter of the ocellus. The longitudinal diameter of the eye is twice the transverse one, 3 times the malar space. Face width 1.5 times its height [T14]. Malar space half as long as the longitudinal diameter of the eye; temples equal to the width of the eye. The ocelli are small; the distance between them and the eyes is almost 4 times the diameter of the ocellus. [Te1]. Width of head twice length, at middle line 2.5 times length [T5].
sculptureface with very fine concentric striae [N]. Face and cheek with more or less concentric fine and semicircular striation; clypeus finely punctate, interspaces shiny. Head above and temple also with fine striation (Fig. 3) [P6]. Vertex finely transversely striated behind ocelli, face with slightly less fine rugae [T14]. Clypeus smooth, shining, face not densely covered with short white hairs [Te1]. Head very finely chagrined, especially on the middle of the face and on the clypeus. There is no border between the clypeus and the face [W2, eurytheca].
colorpalpi yellow-brown [D]. Mandibles are black or blackish, sopmetimes yellow-brown towards the tip. The palpi are pale, rarely with a slight dark tint [W2, eurytheca].
antenna
shape ♀Antennae straight, setaceous, thin, with very many segments. At apex segments so small that they are hard to count [N]. Antenna as long as body, with 29 antennomeres. Third segment 3.3 times as long as broad apically, further flagellomeres gradually shortening and attenuating so that penultimate six flagellomeres (i.e. 23-28) cubic [P6]. 26-28 segments [Th], 26-27 segments, tip often curved [H2]. 25 - 32 segments, bristle-shaped, length of 3rd segment 3 times its width, segments in apical part of flagellum equal in length and width [T14]. Number of antennal segments of ♀ 25-29 [T5]. The antennae are about the length of the body, black, imperceptibly tapered from base to tip, 29 or 30 segments [W2, eurytheca].
shape ♂Antennae more tapered [N]. 27 - 30 segments [T7][T14]. Antennae bristle-like, 29-segmented [T5].
colorAntennae in basal part brownish yellow [T4]
mesosoma
shapeMesosoma in lateral view 1.4 times as long as high [P6]. Prescutellar furrow with seven crenulae [P6]. Pair of latero-median tubercules small [P6]. Mesosoma length 1.7 times its height. Propodeum abruptly truncate, without transverse carina, with small lamellar lateral teeth [T14]. Propodeum with obtuse short projections on the sides, with a weakly noticeable field in the middle [Te1]. Propodeum with sharp lateral teeth [W2, eurytheca].
sculptureMesosoma areolate rugose, mesonotum rugulose to confluently punctate, subshiny, before prescutellar furrow and at meeting of notaulices rugose [P6]. Notauli indicated by roughened sculpture [P6]. Mesonotum often with more or less smoothed sculpture, irregularly rugose in front of scutellum; scutellum weakly longitudinally rugose or weakly punctate, shining [T14]. Notauli are weak, rugose at the base [Te1]. Mesonotum quite finely chagrined, scutellum somewhat longitudinally rugose and finely punctated, the rest of the mesosoma very coarsely sculptured [W2, eurytheca]. Mesonotum very finely dotted, punctuated and rough towards the scutellum, which is limited anteriorly by a crenullated groove, and covered with fine, tight, linear dots [M2].
color
legs
shapeHind femur ♀ 3.1 (♂ 2.9) times as long as broad medially. Hind tibia and tarsus equal in length. Hind basitarsus as long as tarsomeres 2-5 [P6]. Hind femur 3 - 3.5 times as long as wide. [T14].
sculpture
colorLegs yellow. Basal two-thirds of hind coxa brownish, hind femur and tibia apically brownish, tarsi 1-3 brownish except pale yellow base of basitarsi 1-3. ♂ dark colour of legs blackish to black and more extended (fig 1). [P6]. Greater part of legs black [T4]. Legs light yellow-brown, hind coxae blackish brown at base. A black-brown spot at back side of hind femur, hind tibia at the top and all tarsi more or less darkened [D]. The hind trochanters and base of the femur are brownish yellow, the apical part of the femur is more or less dark-colored, sometimes the femora for the most part (except for the base) are dark-colored [T5][T14]. ♀ Hind femora entirely brown-yellow (rarely or with somewhat developed dark color on apex dorsally on entire outer half, rarely completely (except base) black. ♂ Hind femora as in dark-colored ♀♀ [T5].
wings
shapeFore wing somewhat shorter than body [P6]. Pterostigma ([3]) 2.1 - 2.7 times as long as wide (♂ 2.3 - 2.9). Radial vein originates from middle to distally from middle of pterostigma [P6]. Veins r and 3-SR equal in length, SR1 faintly curved. R1 one-fifth longer than pterostigma, 1-R1 as long as pterostigma (exceptionally shorter [14]). Vein 3-CU1 twice as long as 2-CU1 [P6]. 1-R1 is shorter than or equal to the length of the pterostigma [T14]. r same length as 3-SR and same length as r-m. SR1 4 times longer than 3-SR. 1-R1 is equal to the length of the pterostigma. 1-CU1 is half as long as 2-CU1 [Te1].
colorWings with metal shine, clear yellow-brown veins [D]. Tegula brownish yellow [P6]. The wings are darkened [T14]. The wings are slightly smoky, tegulae and pterostigma brown [Te1]. The wings have a slight dark tint; pterostigma, parastigma and most veins are black [W2, eurytheca].
metasoma
shapeCarapace in dorsal view 1.66-1.9 times as long as broad posteriorly from its middle, ♂ distinctly broadening posteriorly. In lateral view 2.6 - 3.2 (♂ 3.0 - 3.3) times as long as high behind, less than twice as high behind as basally (fig 7, see vertical four arrows) [P6]. ♀ apex less rounded (in ventral view somewhat incurved). ♂ apically incurved, incurvation as long as hind tarsomeres 2-3 or 3-4 [P6]. The metasoma is oval, its length is twice its width, or a little shorter, relatively weakly bent forward apically [T14]. Metasoma is slightly longer than mesosoma, oval [Te1]. Length of metasoma 1.9 times width [T5]. Oval metasoma, as long as the head and mesosoma [M2].
sculptureCarapace longitudinally striate, interstriations transversely rugose, hind third of carapace rugose to densely rugose [P6]. Sculpture of the metasoma in the basal half is not coarsely longitudinally rugose, with sinuous and anastomosing rugae. reaching the middle of the metasoma [T14]. Metasoma with longitudinal rugae at the base, irregularly rugose towards the apex [Te1]. Metasoma covered with very fine and reticulated sculpture [M2].
color♀ Carapace basally either fully straw yellow, or more or less divided by a blackish to black streak in a pair of spots. ♂ carapace basaly not yellow [P6]. The metasoma is yellow at the base or with a pair of yellow spots (sometimes fused; in the male it is almost always black) [T14]. ♀ Metasoma at base with somewhat developed yellow spots, often fused and forming yellow band, rarely metasoma completely black. ♂ metasoma entirely black [T5].
♀ ovipositorOvipositor sheath short [P6], concealed, straight [N]. The ovipositor is hidden or weakly protruding [T14]. The ovipositor is short and straight [Te1].
♂ apertureApical foramen elliptic and twice as wide as high (fig. ) [P6] The male apical aperture is oval, 0.3–0.5 times the width of the metasomal apex. The apical aperture is dark-colored or yellowish [T7][T14]. Aperture oval, width 1.7 times height and 0.40 width of metasoma; middle process occupying about half height of opening [T5]. A large transverse oval opening, rimmed and fringed all around [W2, eurytheca].
other info
distributionDistribution Western Europe [T4]. BE,CH,DE,FR-F,GB-G,NL,PL,SE [FE]
remarksThe description of ♂ by Hellen (1958), ♀♂ Telenga (1941), ♀ Tobias (1976, 1986) are not valid, describing the wrong species [T5].
hosts
