Colobaea americana Steyskal
Creators: name: Bratt, Albertus D.
name: Knutson, Lloyd V.
name: Murphy, William L.
name: Daniels, Anthony A.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Sciomyzidae
Colobaea
Colobaea americana

description: Colobaea americana
Egg (Fig. 6) (based on 10 specimens from Geneva, New York, USA). Length 0.36–0.40 mm; greatest width 0.12– 0.14 mm. Robust, anterior end smoothly rounded. Ventral surface slightly more convex than dorsal surface in lateral aspect. Chorion finely punctate, sculptured into reticulate pattern, longitudinal ridges strongest, producing noticeable striated appearance.
First-instar larva (based on 10 specimens from Geneva, New York, USA). Length 0.70–1.00 mm; greatest width 0.15–0.20 mm. Basal rings of sensory papillae large, lightly pigmented; post-oral and segmental spinules lightly pigmented. Segmental spinules and spinules on posterior end small and sparse.
Cephalopharyngeal skeleton light brown, cornua slender, mouthhooks long, slender. Length 0.08–0.09 mm. Indentation index 72–81.
Posterior end with three pairs of marginal lobes; spiracular tubes 0.015 mm long. Float hairs long, slender.
Second-instar larva (based on five specimens from Geneva, New York, USA). Length 1.2–2.0 mm long; greatest width 0.2–0.4 mm. Anterior spiracles with 12–14 marginal papillae, bifid, papillae tightly covered by integument.
Cephalopharyngeal skeleton 0.11 mm long. Mouthhooks contiguous apically, widened to articulation with hypostomal sclerite. Indentation index 86.
No spinule band on segment III. Lateral pads with spinules.
Posterior spiracular disc with three pairs of peripheral lobes (Fig. 13); dorsal lobes very small, ventral and ventrolateral lobes appear as welts, subequal; lateral protuberances small. No mammillae visible above ventral lobes. Three groups of hyaline float hairs at margin of spiracular plates.
Third-instar larva (Fig. 31) (based on 10 specimens from Geneva, New York, USA). Length 1.5–3.0 mm; greatest width 0.3–1.0 mm. Body tapering, anterior half slender, posterior part larger, dorsoventrally compressed, narrowing abruptly to small posterior spiracular disc (Fig. 49). Lateral welts large, obscuring small lateral pads. Anterior spiracles bifid, no prismatic spots, 14–16 marginal papillae, integument not tightly enclosing each papilla (Fig. 8). Cephalopharyngeal skeleton (Fig. 38) 0.26 mm long. Indentation index 80. Dorsal and ventral cornua slender. Mouthhooks long, slender, ventrally directed. Ventral arch with 25–30 teeth. Dorsal cornu long, slender with elongate, complete window; ventral cornu narrow with small, complete window. Margins of cornua entire.
Spinules very sparse and lightly pigmented, segment III without ventral spinule patch, segment IV with undivided ventral spinule patch, segment V with two-part patch, segments VI–XII with three-part patches. No dorsal spinule patches or scales. Lateral pads with spinules.
Posterior end with four pairs of lobes (Fig. 15). Ventral and ventrolateral marginal lobes large, subequal; lateral protuberances large, rounded; dorsal lobes very small. Mammillae at bases of ventral lobes. Small, sparse spinules on lobes and outer part of disc. Peritremes, slit margins, and stigmatic scars lightly pigmented; margin of peritreme at outer end of each spiracular slit with low, spinelike process (Fig. 49).
Puparium (Figs 25, 44) (based on 10 specimens from Geneva, New York, USA). Length 2.0–3.0 mm; greatest width 0.7–1.1 mm. Formed to fit inside snail shell. Body form robust. First three segments not contracted but attenuated and laterally expanded to occlude snail shell aperture; next five segments contracted, dorsally depressed by shell whorl; last segments abruptly narrowed to small posterior spiracular disc.
Integument subshiny, finely wrinkled with minute punctations, thick. Anterior spiracles and dorsal cephalic cap blackish brown; remainder dark reddish brown. Primary integumentary folds apparent; secondary integumentary folds obscure; lateral intersegmental pads visible. Ventral spinule patches apparent, spinules dark.
Anterior spiracles bifid, strongly protrudent from anterolateral angles of cephalic cap. Posterior spiracles protrudent, dorsally directed. Peripheral lobes of posterior end slightly reduced.
description: Published as part of Bratt, Albertus D., Knutson, Lloyd V., Murphy, William L. & Daniels, Anthony A., 2020, Biology, immature stages, and systematics of snail-killing flies of the genus Colobaea (Diptera: Sciomyzidae), with overviews of aspects of the tribe Sciomyzini, pp. 1-64 in Zootaxa 4840 (1) on pages 38-39, DOI: 10.11646/zootaxa.4840.1.1, http://zenodo.org/record/4405544