Chelonus decorus
authorMarshall 1885
synonyms
body
shapelength 2 lin. (5 mm) [M]. 5-6 mm [Te1]. ♀ 4.4mm [He].
colorBlack; Body scarcely shining [M].
head
shapeHead with a transverse vertex, slightly contracted behind the eyes, cheeks not dilated [M]. The head is transverse, slightly roundly narrowed posteriorly. Malar space 0.5 times 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 3 times the diameter of the ocellus [Te1]. Head transverse, twice as wide as long. Face width is twice the height, with a mid-longitudinal carina under the scapus. Temple width same as transverse eye diameter. POL :OOL = 0.6 [He].
sculptureHead reticulate-rugose, orbits and cheeks striolated, the face transversely ; clypeus punctulate, shining; frontal fovea small, shining, somewhat rugulose [M]. Head finely wrinkled, dull. Clypeus densely punctate at base, smooth and shining at apex [Te1]. Face with horizontally striated and punctated. Clypeus finely rugulose and shiny. Temples striated
colorPalpi and tips of mandibles orange-brown, the former darker at the base [M].
antenna
shape ♀Antennae dilated and compressed beyond the middle, not much attenuated at the tips, shorter than the body. ♀ antenna with 27 segments [M]. Antennae filiform, not compressed behind the middle, 27-32-segmented [Te1]. Antennae with 30 segments, becoming wider and shorter after the middle [He].
shape ♂Antennae filiform, not compressed behind the middle, 27-32-segmented [Te1].
color
mesosoma
shapePropodeum disk inclined from the base, truncate behind, the angles hardly denticulated [M]. Propodeum on the sides with sharp teeth, in the middle with a sharp transverse ridge. Notauli are poorly visible [Te1]. pre-scutellar groove with 8 ridges. Propodeum with transverse carina and sharp lateral teeth [He].
sculptureMesonotum in front variolose, rather shining, reticulated before the scutellum, which is thickly variolose, margined with coarser punctures. Propodeum coarsely reticulated [M]. Mesosoma and propodeum coarsely wrinkled. Scutellum in the middle shining [Te1]. Mesonotum before scutellum coarsely reticulate. The middle part of the scutellum is smooth, propodeum coarsely reticulate [He]
color
legs
shapeLegs are slender. The spurs of the hind tibia are equal to ½ of the first tarsus segment [Te1]. Spurs of hind tibiae shorter than half of metatarsus [He].
sculptureHind coxae slightly rugose [Te1].
colorLegs orange-brown. Hind femora black except the tips. Fore- and middle tibia black at the base, hind tibiae dark at base and tip. All the tarsi yellowish-brown with dark tips [M]. Legs are black; apex of femora, fore tibia entirely, middle and hind tibia in middle and base of hind tarsus reddish white [Te1]. The coxae and trochanters, basal half of fore femur and hind femur black except the tip [He].
wings
shapeMarginal cell broader but not longer than the stigma; SR1 slightly concave outwardly; radius of the hind wings sinuated. wingspan 9.4mm [M]. 3-SR much longer than r and equal to r-m. SR1 almost three times longer than 3-SR. 1-R1 is equal to the length of the pterostigma. 2-SR is 1 1/2 times as long as 3-SR. cu-a is postfurcal, separating more than 1/3 of the base of the 1st discal cell (1-CU1 > 0.5 2-CU1) [Te1]. 1-R1 is equal to pterostigma length, r has same length as 3-SR, SR1 is straight, and 3 times 3-SR [He].
colorWings dark transparent. Pterostigma and veins dark, costa, parastigma, and vein 1-M brownish-yellow, tegulae black [M]. The wings are light; the pterostigma is black; tegulae are yellow or black; the main segment of the medial vein and the basal vein are yellow [Te1]. Wings light smoky, wing base yellowish brown, parastigma and veins basal half of wing yellowish brown, veins in apical half brown [He].
metasoma
shapeMetasoma longer than the mesosoma, a little wider behind, rounded, not obtuse at the apex. No basal carinae [M]. Metasoma much longer than mesosoma, oval [Te1]. Metasoma ovoid, the metasomal cavity reaches the end of the metasoma [He].
sculptureCovered with the usual oblong reticulations becoming finer posteriorly, the apex rather shining [M]. The longitudinal rugae at the base of the metasoma are distinct [Te1].
colorMetasoma with 2 triangular basal yellowish spots [M]. Metsasoma with 2 yellow spots at the base [Te1]. Metasoma black with two small spots near the base [He].
♀ ovipositorOvipositor concealed [M]. The ovipositor is straight [Te1]. The ovipositor is very short, strong, and hidden under the metasomal cavity [He].
♂ aperture
other info
distributionWestern Europe [T4]. AT,CH,DE,FR-F,GB-G,IE,NL,PL,SE [FE]
remarksAt first sight like C. dispar [fenestratus] ♂ , but the metasoma is considerably longer in proportion, the antennae are much more than 16-jointed, and the sculpture is finer. The yellowish abdominal spots are triangular, and widely separated in the middle [M].
hosts
type description
7. Chelonus decorus, n. s.
Black; metasoma with 2 triangular basal yellowish spots ; palpi and tips of mandibles rufo-testaceous, the former dusky at the base; legs rufo-tcstaceous, fore and middle femora at the base, hind femora except the apex, black; hind tibiae fuscous at both ends; all the tarsi testaceous with fuscous tips. Wings subfusco-hyaline, stigma and nervures fuscous, costa, parastigma, and praebrachial nervure testaceous, squamulae black; radial areolet broader but not longer than the stigma; 3d abscissa of the radius slightly concave outwardly; radius of the hind wings sinuated. Body scarcely shining. Head with a transverse vertex, slightly contracted behind the eyes, cheeks not dilated ; reticulato-rugose, orbits and cheeks striolated, the face transversely ; clypous punctulate, shining; frontal fovea small, shining, somewhat rugulose. Antennae ? 27-jointed, dilated and compressed beyond the middle, not much attenuated at the tips, shorter than the body. Mesomesosoma in front variolose, rather shining, reticulated before the scutellum, which is thickly variolose, margined with coarser punctures. Metamesosoma coarsely reticulated, the disk inclined from the base, truncate behind, the angles hardly denticulated. metasoma longer than the mesosoma, a little wider behind, rounded, not obtuse, at the apex, depresso-cylindrical, covered with the usual oblong reticulations becoming finer posteriorly, the apex rather shining; basal carinae none. Terebra concealed. ♀. Length, 2; wings, 3 3/4 lin.
At first sight like C'. dispar, sp. 8, ♀ , but the metasoma is considerably longer in proportion, the antennae are much more than 16-jointed, and the sculpture is finer. The yellowish abdominal spots are triangular, and widely separated in the middle.
Data used in the multi-access key
These data are collected from the species descriptions and redescriptions, from published figures and photographs and from own measureements and observations. For a description of the different variables and value classes see this
pdf.
| morphology |
| basic information | female | male |
| body length (mm): | (4.2) 4.2 - 5.5 (6) | (4.2) 4.2 - 5.5 (6) |
| number of antennal segments: | (26) 26 - 32 | (27) 27 - 32 (33) |
| head, dorsal view |
| Head width : length | wide | wide |
| Temples narrowing - widening | narrowing, parallel | narrowing, parallel |
| Eye length : temple length | --- | --- |
| Roundness temple | strong, medium, weak | strong, medium, weak |
| POL : OD | --- | --- |
| Ocellar triangle shape | --- | --- |
| Excavation of head | --- | --- |
| head, lateral view |
| Head height : length | --- | --- |
| Eye height : length | --- | --- |
| Temple length : eye length | very short, short | very short, short |
| head, frontal view |
| Head width : height | --- | --- |
| Face width : height | wide | wide |
| Eyes converging ventrally | --- | --- |
| EH : MSL | short | short |
| Clypeus width : height | --- | --- |
| Clypeus extending above bottom of eyes | --- | --- |
| Tentorial pits | --- | --- |
| Shape of lower margin clypeus | --- | --- |
| antennae |
| Antennal shape | clearly widened | filiform, not widened |
| Segment 3 length : width | --- | --- |
| Penultimate segment length : width | --- | --- |
| Length of antenna : length of body | 3: long | --- |
| mesosoma, lateral view |
| Length : height | --- | --- |
| transverse carina | present, well developed | present, well developed |
| lateral teeth | very small, very weak, weak, small, short, present | very small, very weak, weak, small, short, present |
| mesosoma, ventral view |
| Prepectal carina lamelliform | indistinct | indistinct |
| legs |
| Hind femur length : width ratio | --- | --- |
| Hind tibia length : hind tarsus length ratio | --- | --- |
| Hind tibia (longest) spur length : metatars length ratio | short, long | short, long |
| wings |
| Vein 1-R1 length : pterostigma length | long | long |
| Vein r length : vein 3-SR length | short | short |
| Shape vein SR1 (straight / concave / convex) | slightly concave, straight or S-shaped | slightly concave, straight or S-shaped |
| S-shape vein SR1 | apically concave, not S-shaped, apically convex | apically concave, not S-shaped |
| cell M : cell Sm2 | --- | --- |
| Pterostigma length : width ratio | --- | --- |
| Angle between radial vein (r) : vein 1-R1 | --- | --- |
| metasoma, dorsal view |
| Length : width ratio of metasoma | --- | --- |
| Shape of metasoma | --- | --- |
| metasoma, lateral view |
| Length : height ratio of metasoma | --- | --- |
| posterior : anterior height ratio of metasoma | --- | --- |
| Position of maximum height | --- | --- |
| metasoma, ventral view |
| Metasoma posteriorly curved forwards | (almost) not incurved | (almost) not incurved |
| male apical aperture |
| Aperture width : metasoma width | no aperture | no aperture |
| Aperture shape | n. a. | n. a. |
| Median process shape | n. a. | n. a. |
| sculpture |
| head |
| general coarseness | fine | fine |
| clypeus |
| coarseness punctation | punctulate | punctulate |
| density punctation | --- | --- |
| face |
| sculpture type | striate, reticulate | striate, reticulate |
| sculpture direction | transverse | transverse |
| vertex and temple |
| sculpture type | striate (striolate), striate-rugulose | striate (striolate), striate-rugulose |
| mesonotum |
| sculpture type | notauli slightly distinct | notauli slightly distinct |
| scutellum |
| middle | smooth | smooth |
| lateral | rugulose, rugose / striate | rugulose, rugose / striate |
| metasoma |
| base - mid sculpture | longitudinally rugose / rugose-striate | longitudinally rugose / rugose-striate |
| sculpture at apex | rugulose | rugulose |
| coarse / fine boundary | mid (50 - 70%) | mid (50 - 70%) |
| color |
| head |
| mandibles color pattern | light tip | light tip |
| palpi, lightest color | brown, red | brown, red |
| antennae |
| scapus, lightest color | black, dark brown | black, dark brown |
| segment 3 and 4, lightest color | black, dark brown | black, dark brown |
| legs |
| fore coxae lightest colour | dark | dark |
| fore femur lightest colour | medium dark, medium light | medium dark, medium light |
| fore femur color pattern | tip light, base dark | tip light, base dark |
| hind femur lightest colour | medium dark, medium light | medium dark, medium light |
| hind femur color pattern | tip light | tip light |
| hind tibia lightest colour | medium light | medium light |
| hind tibia color pattern | narrow light ring, wide light ring | narrow light ring, wide light ring |
| hind basitarsus lightest colour | medium light | medium light |
| hind tarsus segment 2-3 lightest colour | dark, medium dark | dark, medium dark |
| wings |
| middle veins lightest colour | dark, medium dark | dark, medium dark |
| basal veins lightest colour | medium light, light | medium light, light |
| metasoma |
| metasoma colour pattern | color only on basal third | color only on basal third |
| metasoma lightest colour | light | light |
| metasoma base, colour pattern | 1, 2 or 4 spots | 1, 2 or 4 spots |
| metasoma base, light spots | 2 small spots, 2 large spots | 2 small spots, 2 large spots |
| metasoma base, light band | n.a. | n.a. |
