Prodiamesa olivacea (Meigen)

Namayandeh, Armin, Bilyj, Bohdan, Beresford, David V., Somers, Keith M. & Dillon, Peter J., 2012, 3324, Zootaxa 3324, pp. 1-65 : 16-17

Prodiamesa olivacea (Meigen)

Figs 9A–E

Diagnosis. Large larva up to 15 mm long. Head pale brown with dark pattern ( Fig. 9A) on ventral side; SI seta pectinate distally; premandible ( Fig. 9B) with two apical teeth, brush not evident; antenna ( Fig. 9C) 4-segmented, 3 rd segment tiny, not annulated, blade longer than flagellum, AR 2.7; mandible ( Fig. 9D) with 4 inner teeth, the 3 rd tooth being somewhat more prominent; mentum ( Fig. 9E, III instar) with 14 teeth, including 6 lateral teeth, median pair recessed between large trifid 1 st laterals, 5 th lateral larger than the 4 th; VM plate enlarged with well developed beard.

Notes. The head capsule of a newly molted third instar ( Fig. 9E) hasn’t developed the characteristic dark ventral pattern, but is seen in Fig. 9A of a less then desirable slide-mount of a fourth instar. The complete ventral pattern on an intact head is illustrated in Moller Pillot (1984, fig.VI.41a) and Makarchenko (1985, fig. 411). This species is widespread in the USA and one would expect it likewise to be in Canada, but according to the recent world catalog ( Ashe & O’Connor 2009) there has been no published record of this species in Canada, apparently making this the first record.

Ecology and habitat. The species inhibits springs, rivers, streams and littoral zone of the lakes. The species is tolerant of moderate pollution ( Epler 2001, Saether 1983). The species is reported as common in sandy or silted sediments of slow flowing streams ( Hudson et al. 1990, Saether 1983). In the study streams this species occurred in all habitats.

Sampling sites. Killarney, Arrowhead and Algonquin Provincial Parks. Nearctic distribution. First published record for CANADA: Ontario. USA: Colorado, Georgia, Main, Massachusetts, Michigan, New Jersey. North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee. Also occurs in Greenland .