Chelonus basalis
authorCurtis, 1837
synonyms
body
shapeless than 2.5 mm [C]. 1.6 - 1.9 mm [LT1][T14]. 1.5 - 2.0 [T4]. 2 - 3mm [Te1].
colorBlack, minutely punctured, pubescent [C][M].
head
shapeScarcely widened and rounded behind eyes, about temples narrower than about eyes; in dorsal view 1.6 times as broad as long, in frontal view 1.1 times as broad as high; 1.2 times as wide as mesosoma. Ocellar triangle as long as OOL. POL 3 times longer than diameter of a posterior ocellus. Temples in dorsal view 1.4 times longer than transverse diameter of eye. In frontal view eye 2.5 times longer than transverse diameter, 1.5 times as long as malar space. Face almost twice as broad as high and 1.4 as broad as longitudinal diameter of eye, twice higher than clypeus. Maxillary palpi short, as long as height of face [LT1][T14]. The head is transverse, noticeably roundly narrowed posteriorly. The face is twice as wide as high; malar space equal to 1/2 of the longitudinal diameter of the eye; temples equal to the width of the eye. The ocelli are small; the distance between the ocelli is 3-4 times the diameter of the ocellus [Te1].
sculptureHead densely and finely punctate. Face without any strigosity. Frons finely punctate. Vertex behind ocelli unclear transversally striate. Temple very finely longitudinally striate, about eyes without. Clypeus finely punctate, more or less shining [LT1] Head gently rugose, matt. Clypeus smooth, shiny [Te1].
colorPalpi brown [LT1]
antenna
shape ♀Antennae with 16 segments [C][LT1]. Antennae shorter than body. Scape widened, twice as wide as 3-6th segments. Basal segments of flagellum narrowed, 5-12th segments of flagellum a little enlarged (1.5 times as wide as the first one and a little narrower than scape); 3rd segment 3 times as long as wide, apical segments 1.5-1-7 times as long as wide [LT1]. Antennae half as long as body, filiform, 16-segmented, scapus ovoid [Te1].
shape ♂Antennae shorter than body, 19-segmented: scape narrower than in female, 1.5 times as wide as segments of flagellum; segments of flagellum not enlarged; 3rd segment 3 times as long as wide, apical segments 1.7-2.0 times as long as wide [LT1][T14].
color
mesosoma
shapePropodeum bituberculate, with 2 carinas down the back, slightly toothed at the apex [C]. ♀ 1.6 times as long as high. ♂ Longer than female, 1.7 - 1.8 times as long as high; laterally almost equal to length of metasoma. Propodeum centrally with two more or less clear longitudinal carinas, with well developed transverse carina and lateral tubercles [LT1]. Propodeum in the middle with a transverse ridge, laterally with short teeth [Te1].
sculptureMesonotum punctate rugose, prescutellar sulcus sculptured and area before it with some coarser sculpture. Sides of mesonotum punctate rugose. Scutellum punctate. Propodeum softly rugulose punctate, without longitudinal elements; keel between two longitudinal carinas smoothe [LT1]. Mesonotum finely rugose. The notauli are not distict [Te1].
color
legs
shapeHind femur 3.5 times as long as broad. External spur slightly longer than internal, almost reaching a half of metatarsal segment. Fifth metatarsal segment as long as third, 1.3 times shorter than second one and 1.3 times longer than fourth one [LT1].
sculpture
colorLegs black, tips of fore femora, tibiae and base only of hind [tibiae?] yellow-red [C]. ♀ Legs dark: coxae black; fore femora black with brown apex, tibiae brown with brown-yellowish basal part, tarsi brownish; hind femora black, tibiae brown with brown-yellowish basal part, tarsi brown. ♂ Legs darker than female: coxae black; fore femora black with brown apex, tibiae and tarsi dark brown; hind femora and tibiae black, tarsi dark [LT1]. Legs are black; all tibiae with a red pattern [Te1]. Fore tibiae brownish yellow at base, other parts of legs mostly brown. ♂ Hind tibia dark-colored [T14].
wings
shapeMarginal cell 1.5 times larger than cell Sm2. 3-SR 1.2 times as long as r, 3.5 times shorter than SR1. Distance from cu-a to 1-M equals to length of cu-a [LT1]. Vein r longer than 3-SR and equal to r-m. 1-R1 is shorter than the pterostigma. 1-CU1 almost 0.5 times 2-CU1 [Te1].
colorWings slightly darkened, stigma large and darker [C]. ♀ Wings very faintly (almost not) infuscate. Pterostigma and veins somewhat brown-yellowish. ♂ Wings more or less infuscate, mainly on basal part. Pterostigma and veins brown [LT1].
metasoma
shape♀ Carapace elongate-oviform with more or less parallel sides, 2.0 - 2.2 x as long as broad, basally slightly incurved (on its 1/7 length). In lateral view almost parallel sided [LT1]. Metasoma is slightly longer than the mesosoma, oval [Te1]. Metasoma elongated-oval, apically bent forward by 0.15 times its length, twice as long as wide [T14].
sculptureCarapace with a few fine winding longitudinal rugulae at its 1/3 part; ♀ other 2/3 without any longitudinal scuplture, ♂ rugulae somewhat continuing till its 1/3 part [LT1]. Metasoma completely rugose, but without sharp longitudinal rugae [Te1].
colorBase of metasoma yellow-red [C]. Carapace with yellow belt covering almost 1/2 of its length, laterally reaching almost 2/3 of its length. Males are almost black [LT1]. Base usually whitish, but sometimes brown or completely black [H2].
♀ ovipositorOvipositor hidden [LT1]. The ovipositor is short [Te1].
♂ apertureApical abdominal aperture small, oval [bean]-formed, 0.2 times as broad as carapace [LT1].
other info
distributionAT, DE, CZ, DK, GB, PL, SE [FE].
remarksThis species is clearly defined from other species by small body (less than 2mm), rather widened head behind eyes and fine sculpture (almost without rugosity). Female possesses a little enlarged 5-12 segments of flagellum and yellow belt on basal half of carapace. Males are almost black with infuscate wings and a little longer carapace (2-2.2 times as broad a long), apical abdominal aperture small and oval or beanformed [LT1].
hosts
