(Meigen, 1818)
Body
Large larvae up to 15 mm long. The gula with a large black spot. Body setae pale and indistinct. The anterior and posterior parapods are separate and bear rows of claws. Procercus is about twice as high as wide with 8 anal setae and 2 subapical. Two pairs of anal tubules present (Wiederholm, 1983).
Head
The gula with a large black spot Prodiam oliv head ventral.
Antenna
The antenna consists of four segments. First segment long and segments 3 and 4 are small. The blade is longer than the flagellum. Lauterborn organs are small but distinct.
Mentum
The mentum has two low median teeth and 7-8 pairs of lateral teeth including the 2 small teeth on the first lateral pair. The ventromental plates are very large and resemble those of Chironomini Prodiam oliv mentum. A beard with a fringe of very long hairs is present.
Labrum
The pecten epipharyngis consists of three scales, SI is serrate distally and the labral lamellae are broad and pectinate. The premandible has 2 apical teeth (Wiederholm, 1983).
Mandible
The mandible has an apical tooth and 4 inner teeth. The seta interna has serrate branches (Wiederholm, 1983).
Differential characteristics
The large size (up to 15 mm) and the very large ventromental plates are distinctive for the genus Prodiamesa. P. olivacea differs from P. rufovittata by the larve dark spot on the gula Prodiam oliv head ventral and the long setae on the ventromental plates Prodiam oliv mentum.