Milichiella Giglio-Tos - genus description

Adult

Head:

Frons with eye margins parallel in female and usually converging anteriorly in male; postocellar setae parallel, ocellar setae lateroproclinate; 2-3 orbital setae, anterior orbital seta lateroproclinate, middle seta lateroreclinate and posterior seta medioreclinate or absent; interfrontal setulae present as well as setula between supra-antennal seta and eye margin. Antenna with basoflagellomere small and rounded, arista usually short pubescent. Eye usually enlarged, more than 1.5x as high as wide; bare; with anterior ommatidia slightly larger than posterior ommatidia [?]; posterior eye margin often with notch in middle and/or an emargination in the lower half; aethiops group without notch but with posterior eye margin separating from head margin ventrad. Gena narrow. Proboscis typical for Milichiinae, geniculate, usually not elongate; labellum with 4 pseudotracheae.

Thorax:

Acrostichal setulae scattered, usually 1 large prescutellar pair but up to 3 more large pairs between dorsocentral rows; 2-5 dorsocentral setae, 1 or more presutural setae, in some species a row of long presutural setae across mesonotum; 2 [?] postsutural supra-alar setae; 1 [?] postalar seta; 1-2 postpronotal seta; 2 notopleural setae; anepisternum and anepimeron [?] bare; 1-5 katepisternal setae; 2 scutellar setae. Basisternum large and V-shaped, precoxal bridge absent.

Wing:

Generally hyaline, sometimes brownish, tip of R1 sometimes with brown spot; costa broken twice, shortly beyond humeral crossvein and at end of subcostal; costa extended to vein M1; row of costal spinules extended shortly beyond apex of R2+3; subcosta ending in costa, not fused with vein R1 apically [?]; discal cell separate from cell bm by crossvein bm-cu; veins A1 and CuA2 form cell cup, A1 ends shortly behind cell cup; A2 absent.

Legs:

Forefemur sometimes strongly setulose posterodorsally in males; midfemur sometimes with row of long setae posteroventrally; mid and hind basitarsomeres usually with yellow brush of setae.

Male abdomen:

Ground colour generally brownblack, but yellow in some species. Tergites shiny or more or less microtomentose, often with silvery pattern. Silvery microtomentum quite long in some species. The length of the tergites has been used as a character in some species descriptions, however, usually this is based on an artefact, because tergites 3 and 4 are partly drawn beneath tergite 2. The shape and chaetotaxy of sternite 4 and 5 is variable and can be used to differentiate species or species groups.

Male terminalia:

Surstylus fused with epandrium; cerci separate; subepandrial sclerite present, with pair of setulae; postgonite absent; pregonite usually bearing a few setulae but strongly setulose in M. lacteipennis and M. …; phallapodeme fused with hypandrium, posterolateral arms of hypandrium reaching base of surstyli; distiphallus membranous, short; ejaculatory apodeme
slender, elongate.

Female abdomen:

Typical for Milichiidae. Shape of sternite 4 and 5 varies and could possibly be informative for the phylogenetic analysis. However, females are unknown or questionable for most species.

Female ovipositor:

Long and retractable; tergites 6-8 and sternites 6-7 complete, sternite 8 longitudinally divided, cerci usually paired but fused in M. iberica (Carles-Tolrá 2001) and possibly dorsally fused in some other species (M. bakeri, sp. 68).

Female reproductive system:

Spermathecal ducts rolled up into one longish coil or with very tightly wound, spindle-like spermathecal duct coil (Brake 2000).

Immature stages

Larva:

Third instar larva: Slender, elongate, narrower on anterior quarter. Cephaloskeleton with slender, strongly slerotised mouthhooks, with sharply pointed apex and narrow, relatively acute posteroventral apodeme. Dental sclerite rounded tetragonal, weakly sclerotised. Intermediate sclerite separate from pharungeal one, relatively robust; lateral rods strongly sclerotised and connected by a slender, strip-like cross-bridge. In front of the cross-bridge is a complex subhypostomal sclerite, composed of a posterior convex plate bearing 2 lateral (anteriorly-directed) and 2 small medial projections, and an anterior slender, v-shaped sclerite (the latter perhaps homologous with ligulate sclerite). Epistomal plate (situated anterodorsally between arms of intermediate sclerite) membraneous, with only the margins of its 2 small perforations pigmented and thereby visible even in ventral view. Parastomal bars very slender but dark and heavily sclerotised. Pharyngeal sclerite very pale, weakly sclerotised, except for anterior part. Dorsal bridge simple, not separated by an incision from rest of pharyngeal sclerite. Dorsal cornua slender, posteriorly pointed, essentially smaller than ventral cornua; the latter long and broad but without a dorsal apodeme. Ventral cornua joined ventrally by a downward curving trough provided with conspicuous, longitudinal ridges. Cephalic region bilobate, with antenna dorsally near apex of each lobe; facial mask bearing oral ridges. Anterior spiracle with 7-9 (7 in M. argyrogaster and M. lacteipennis, 9 in M. sp. 1) digitiform protuberances arranged in a flattened, semirosette shape. Posterior spiracles borne on widely separated protuberances; each spiracle without peritreme and not on a single plate, but composed of 3 pale yellowish brown, finger-like projections. Each spiracular projection has its own, slightly curved slit and several, slightly ramifying, fine peristigmatal tufts (after Roháček 1995).

Puparium:

Puparium elongate, tapering towards anterior and posterior end. Empty puparium reddish brown, subshining to almost dull, with distinct borders between segments. Anterior (thoracic) part dorsoventrally compressed with shallow but distinct lataeral depressions on both dorsal and ventral side. All thoracic segments sculptured by distinctive, mostly transverse ribs; prothoracic (both dorsally and ventrally) and mesothoracic (dorsally only) segments with more conspicuous ribbed sculpture. Abdominal segments circled by very fine ribs or wrinkles, ventrally each with 1-2 transverse rows of very minute spinulae. Posterior end of puparium more convex and strongly transversely or reticularly (last segment) ribbed. Anus fully visible, encircled by a curved rib (after Roháček 1995).

Egg:

Shape elongate, anteriorly narrower than posteriorly. Chorionic sculpture consists of minute, rounded pits in M. argyrogaster and M. sp. 72, as well as even smaller pits in M. lacteipennis. These pits are arranged in more or less distinct hexagonal fields in M. argyrogaster (Roháček 1995). Micropyle connected by radial ribs with a surrounding ring in M. argyrogaster and radial ribs also visible in M. lacteipennis.

Biology:

Swarming (M. argentiventris, argyrogaster, circularis, frontalis, lacteipennis, longiseta, nigeriae, spinithera, sumptuosa)
Reared from rotten vegetable matter (M. argentiventris, circularis, lacteipennis), decaying wood or bark (M. argyrogaster, urbana).
On flowers of Euphorbia regis jubae (M. bimaculata), Schinus mollis (M. bimaculata, lacteipennis), Umbellifera and flowers of Thapsia villosa (M. iberica), Chalcas (Murraya) exotica, Cocos nucifera, Nothopanax cochleatum, Ochradenus baccatus (M. lacteipennis), Abrame angustum (M. unicolor)
killed by balsa flower, Ochroma lagopus (M. lacteipennis)
near aphids (M. lacteipennis)
light traps (M. lacteiventris)
manure (M. lacteipennis)
kleptoparasitic (M. lacteipennis)

In the Czech Republic, females of M. argyrogaster were observed on the bark of fallen beech trunks, close to fresh holes into brood tunnels of bark beetles Xyloterus domesticus (Linnaeus, 1758) and/or Xyleborus dispar (Fabricius, 1892), probably intending to oviposit
into the bark using the holes of the bark beetles (Roháček 1995). The species flies from about mid-May to the beginning of June (about 3 weeks)…

Based on a rearing experiment with M. lacteipennis from the Canary Islands the pupal stage of this species seems to last about 2 weeks and the whole preimaginal development between 4 and 7 weeks (experiment conducted in Germany in colder temperatures).

Discussion:

Milichiidae online

Milichiella

Classification

Glossary

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Milichiella Giglio-Tos - genus description