Paramyia Williston, 1897

Levesque-Beaudin, Valerie & Mlynarek, Julia J., 2020, Revision of Nearctic Paramyia Williston (Diptera: Milichiidae), Zootaxa 4732 (1), pp. 1-56 : 3-4

Paramyia Williston

Paramyia Williston, 1897: 1 . Type species: Paramyia nigra Williston

Diagnosis. Black or yellow flies with one pair of setulae on lunule; palpus usually short and clavate, but sometimes elongate; proboscis long to very long; crossvein dm-cu absent; comb-like row of setae posteroventrally on hind basitarsus; and basisternum very small and shaped like a narrow triangle.

Chaetotaxy. The chaetotaxy described is that of the Nearctic fauna; the chaetotaxy of the Paramyia from other regions has not been studied.

Head: 2 pairs of frontal setae medioclinate; 3 pairs of orbital setae with the 2 lower pairs long and lateroclinate and upper pair shorter and medio-reclinate (less than half the length of lower orbital seta); 1 paired row of interfrontal setulae (stronger than upper pair of orbital seta), 1 pair of supra-antennal setae (anteriormost interfrontal setulae), 1 pair of setulae between supra-antennal seta and eye margin; ocellar setae as long as orbital setae and almost lateroclinate; postocellar setae cruciate; 1 pair of long lateral vertical setae and medial vertical setae.

Thorax: 1 postpronotal seta, 2 notopleural setae, 1 presutural seta (close to notopleuron); 1 supraalar seta; 2 postalar setae; 2 dorsocentral setae (anterior more than half the length of posterior); 1 intrapostalar seta;1 prescutellar seta (acrostichal); 2 scutellar setae (anterior more than half length of apical; apical pair divergent); 1 minute proepisternal seta and 1 minute proepimeral seta, anepisternum and anepimeron bare, 1 very strong katepisternal seta (upper posterior corner, some thinner seta along posterior side).

Female postabdomen based on P. nitens ( Fig. 2 ). For each species, the abdomen usually closely matches the color of the thorax. The sternites size are fairly standard across species, with sternite 1, 2 and 8 being quite short and sternite 5 being the longest. The amount of setae and their distribution is variable within species, making it unreliable as a character. However, there is a common basal configuration. Sternite 7 usually as a minimum of 6 setae arranged in two rows. First row, with 2 setae, with one at each lateral side of the sternite. Second row, with 4 setae, right at the apical end of the sternite, distributed in group of 2 with a bigger gap in the middle. There are often a few extra setae distributed in the bottom of the sternite, sometimes creating a 3rd row located just above the 1st one, but still with a variable configuration within species. Tergite 7 usually has a minimum of 8 setae arranged in two rows. First row, with a minimum of 2 setae, with one at each lateral side of the tergite, but often with a few randomly placed in between, often closer to center. Second row, with a minimum of 6 setae, right at the apical end of the tergite, separated in two groupings of 3 with a bigger gap in the middle. There are often extra setae located in the 2nd row, while some create a 3rd row just above the 1st one. Still a lot of variation within species. The cerci usually have a pair of long setae apically, which are almost twice as long as the other surrounding setae.

Remarks. Females are highly variable within species making it difficult to identify most species based on morphology; using sequencing is recommended to confirm female identity. The color pattern on the legs were consistent for the males (see key and species description), which is not the cases for females. Additionally, there was no obvious variation in the female post-abdomen.

Figures

FIGURE 2. Paramyia nitens female abdomen (A) sternites, (B) cerci, ventral view, (C) sternite 7, (D) tergite 7. Scale bar: sternites = 0.2 mm, others = 0.1 mm.