Adapted from Rotheray et al. (2000).
Head: face yellow, pollinose except shiny tubercle, white pollinose ventrally becoming more golden on dorsal 1/2, black pilose dorsally, yellow pilose ventrally, black and yellow pilose medially; tubercle distinct, convex, occupying medial 1/2 of face; gena yellow, shiny and bare anteriorly, white pollinose and pilose posteriorly; lunule brownish black; frontal triangle yellowish orange on ventral 1/2 except for brownish black medial macula continuous with dark lunule, blackish on dorsal 1/2, densely golden pollinose, black pilose; eye contiguity long, about as long as frontal triangle; frons yellow to orange on ventral 1/4, black dorsally, yellow pollinose ventrally, greenish-brown pollinose dorsally, black pilose; vertical triangle black, greenish-brown pollinose, black pilose, short, about 2/3 as long as eye contiguity; occiput yellow ventrally, black on dorsal 2/3, white pollinose on ventral 2/3, greenish-brown pollinose dorsally, thick yellow pilose on ventral 2/3, with about 3-4 rows of pile at mid-point, black pilose on dorsal 1/3; antenna orange except apicodorsal 2/3 of basoflagellomere brownish black, black pilose; arista brownish black.
Thorax: postpronotum orange, yellow pollinose; scutum black except yellow notopleuron and postalar callus, densely greenish-brown pollinose except yellow pollinose on notopleuron, yellow and black pilose, some specimens with very indistinct submedial vittae anteriorly; scutellum yellow, rarely dark basomedially, densely yellow pollinose altho more brownish-yellow pollinose basally, black pilose; subscutellar fringe of long black pile in males, greatly reduced in females; anepisternum and dorsad to procoxa yellow, golden pollinose, yellow pilose except for a few black pili posteriorly; katepisternum black on ventral 2/3, yellow dorsally, densely yellow pollinose, yellow pilose; anepimeron yellow on anterior 1/2, darker posteriorly, yellow pollinose, yellow pilose except with black pile intermixed posteriorly; katepimeron yellow, yellow pollinose and pilose; meron dark, yellow pollinose; metasternum yellow, bare; metathoracic episternum yellow, yellow and black pilose; postmetacoxal bridge absent, with metathoracic epimera widely separated; metanotum black; plumula short, unbranched, yellow; calypter orange, with yellow to yellow and black fringe; halter orange; wing brown, microtrichose; alula elongate, about as wide as cell BM, about twice as wide as cell C. Legs: Coxae and trochanters yellow, yellow and black pilose; pro- and mesofemur brownish black except pale on base and apical 1/5 or more, black pilose except for a few pale pile basally; pro and mesotibiae and tarsi brownish, black pilose; metafemur and tarsus black, black pilose.
Abdomen: elongate, parallel-sided, slightly narrowed at apex of 3rd segment and expanded at apex of 4th, as long as wing, about 3 time as as long as thorax; 1st tergum black except yellow lateral margin, sparsely grayish-white pollinose, black pilose with yellow pile intermixed laterally; 2nd tergum black except yellow lateral margin on basal 1/2 and yellow interrupted medial fascia in males, with medial fascia absent in females, dull black pollinose on basal 3/4 except pale areas, subshiny (very sparsely pollinose) on apical 1/4, black pilose; 3rd thru 5th terga black except single yellow fasciae on basal 1/3 but separated from base by their widths or more, with fasciae broad in males and narrow in females; dull black pollinose on basal 3/4 except pale areas, subshiny (very sparsely pollinose) on apical 1/4, black pilose; 1st sternum yellow, yellow pilose; 2rd thru 5th sterna orange, black pilose; male genitalia brownish black, black pilose.
Ocyptamus wulpianus is a very distinctive species; everyone who has seen it has described it as a new species or a new genus. Adults are quite rare in collections, perhaps because they are restricted to the canopy (Rotheray et al. 2000).
Rotheray et al. (2000) considered lost the type of Baccha tricincta and designated a neotype based on male from Tucumán Province, Argentina.
Synonyms:
Baccha phobifer Hull 1943: 50.
Hermesomyia bacchiformis Vockeroth 1969: 122.
Baccha pirata Curran, 1939: 7.
Baccha wulpiana Lynch Arribalzaga, 1891: 250.
Baccha tricincta Wulp, 1888: 376.
Ocyptamus (Hermesomyia) wulpianus (Lynch Arribalzaga, 1891).
Lynch-Arribalzaga, F. (1891-2) Dipterologia Argentina, Syrphidae. Anales de la Sociedad Científica de Argentina 32, 80-99, 118-131,194-202, 247-256, 307-314; 33, 51-58, 111-121, 189-199, 236-253; 34: 33-46, 173-192, 242-280.
Description of third stage larva (from Rotheray et al. 2000).
Overall size and shape: length 10 mm, n=3; larva tapering from anal segment to prothorax (width anal segment 3.2 mm to width prothorax 0.3 mm); 7th and 8th abdominal segments forming a single enlarged unit without an indented margin separating segments as occurs between rest of abdominal segments; larva somewhat dorsoventrally flattened as shown by cross-section and lateral sensilla group 4 being almost on same horizontal line as sensilla 5 and 6 rather than above these sensilla as occurs in more subcyclindrical larvae; truncate posteriorly with a pair of rounded projections about 2.5 mm long bearing sensilla; larva translucent, lacking an obvious colour pattern and thereby taking up colour of the background substrate, except for black hind gut and surrounding white fat body; vestiture on the dorsal surface of entire body papillose and uniformally pale; sensilla pattern same as other Syrphidae (Rotheray and Gilbert 1999).
Head: antennomaxillary organs mounted on a fleshy projection apparently formed from dorsal lip and base of antennomaxillary organs. Cephalopharyngeal skeleton typical for syrphine larvae (Roberts 1970) with anterior ends of labrum and labium drawn out to a sharp point and mandibles reduced to a pair of thin stylets which lie lateral to sharpened tips of labrum and labium.
Thorax: lateral lips without a black sclerotised apex, but fleshy and covered with needle-like spicules; these needle-like spicules extending over ventral margins of prothorax and anterior part of mesothorax and also present medially on the ventral surface of metathorax.
Abdomen: ventral sensilla 11 not anterior to sensilla 9 and 10 on abdominal segments 1-6; dorsal and lateral abdominal sensilla 1-6 with a single seta just longer than basal papilla; ventral sensilla lacking setae; ventral surface of 7th and 8th abdominal segments with a disc-like sucker with a raised rim; crescent-shaped anus within sucker; sensilla 10/11 anterior to anus within sucker; sensilla 7/8 and 9 of the 7th abdominal segment outside sucker; sensilla 10/11 of anal segment posterior to anus within sucker; flattened ventral surface outside sucker shagreened, not covered with needle-like spicules; rest of abdominal ventral surface with shagreened areas otherwise smooth, without suckers or grooves; locomotory prominence on each segment 1-6 forming a transverse bar, not developed into a pair of separate structures.
Posterior respiratory process: length 1 mm, basal half tapering towards a mid-point constriction and matt with a rugose surface sculpture; upper half above constriction with 3 spiracular openings mostly on ventral surface with circular scar at tip; lower pair of openings longer than upper two pairs.
Description of puparium (from Rotheray et al. 2000).
Length: 7-9 mm; inflated anteriorly, dorso-ventrally flattened posteriorly. Distal part with a dark brown marking extending to inflated portion. Pupal spiracles absent.
From Rotheray et al. (2000).
Larvae of O. wulpianus occur in bromeliads. Observations revealed that they are predators of aquatic insect larvae. In culture tubes, Ocyptamus larvae were found frequently with the anterior half of the body under and the posterior half above the water. However, larvae also spent extended periods (several hours) underwater. Larvae were able to move forward, backward and sideways using mouthparts and suckers to hold on. Movements were initiated by the mouthparts gripping the substrate. The anal segment was then lifted slightly, moved to a new position, and reapplied to the substrate and the cycle repeated.
These aquatic predators used a sit-and-wait strategy to catch prey. However, they are probably capable of more active searching if, for example, they are starved. Potential prey appear to be detected via tactile cues from prey movement. In response, the front end of the larva lashed out and prey was captured by the thorax that was wrapped around the prey. The mouthparts seemed to pierce the prey but feeding did not always occur. If feeding did not occur, the larva held on to the struggling prey for several minutes until they became inactive. The prey was then released. The immobilised prey appeared to be paralysed or dead. Rotheray et al. (2000) suggested the use of venom in the saliva as a means to subdue prey, although it is unclear that venom is used by these predators.
Immobilised prey examined with a binocular microscope at the point where Ocyptamus larvae held on to them, showed little external sign of the attack. In culture tubes immobilised prey were often fed on by Ocyptamus larvae several hours or days later. When feeding the larva pierced the integument of the prey, inserted the mouthparts, and removed the haemolymph and soft tissues in a way similar to other syrphine predators of soft-bodied Homoptera. Ocyptamus larvae attacked anything that came within reach, but are probably effective only at capturing soft-bodied prey, such as larvae of other insects. In culture tubes they fed on larvae of craneflies (Tipulidae), mosquitoes (Culicidae), and aquatic beetles (Coleoptera, Helodidae), all of which were common in bromeliads. They also attacked and fed on syrphid larvae from other habitats, such as Ornidia obesa (Fabricius) from decaying coffee seeds and Quichuana angustiventris (Macquart) from heliconias when introduced experimentally into the culture tubes. Cannibalism, however, was not observed. Prey varied in size from 5x1 mm mosquito larvae to 18×4 mm tipulid larvae, suggesting that these predators have a wide prey range, both in terms of size and taxonomic affinity.
unless otherwise stated