Orthocladius (Orthocladius) rhyacobius Kieffer, 1911

Magoga, Giulia, Montagna, Matteo, Marziali, Laura, Rossaro, Bruno & Disaa, 2017, Revision of type and non-type material assigned to the genus Orthocladius by Goetghebuer (1940 - 1950), deposited in the Royal Belgian Institute of Natural Sciences (Diptera: Chironomidae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 57 (2), pp. 723-749 : 739-741

Orthocladius (Orthocladius) rhyacobius Kieffer, 1911

( Figs 53‒58 )

Orthocladius (Orthocladius) rhyacobius Kieffer, 1911: 181 .

Material examined. 1 ♁ pinned labelled: ‘ O. oblidens Edw. Brno 1937 (Zavrel) // R.I.SC.N.B. 18.073 / Coll. et det. M. Goetghebuer’; 1 ♁ in isinglass labelled: ‘ Orthocladius rhyacophilus K. Brno, Zavrel // R.I.SC.N.B. 18.073 / Coll. et det. M. Goetghebuer’, all now mounted on slides.

Comments. The two specimens apparently come from the same locality and are conspecific. The dorsal lobes of the inferior volsellae and the absence of virga fit the description of O. rhyacobius Kieffer, 1911 , not with that of O. oblidens (Walker, 1856) ( ROSSARO et al. 2003) .

KIEFFER (1911: 181‒182) separated O. rhyacobius from O. rhyacophilus by the color of the thoracic vittae (black in O. rhyacophilus versus yolk-colored ‘vitellines’ in O. rhyacobius ) and by the relative lengths of palpomeres (Pm) 3 and 4, with the Pm 3 being longer than Pm 4 in O. rhyacobius (‘articles 2 des palpes plus long che le 3’) versus the reverse in O. rhyacophilus (‘articles 2 des palpes plus court che le 3’). It is emphasized ( SPIES & SAETHER 2004: 25‒26), that Pm 3 and Pm 4 correspond to articles 2 and 3 of KIEFFER (1911). All the examined adult specimens of various species in Orthocladius s. str. that are present in the Department of Food, Environmental and Nutritional Science at the University of Milano (DeFENS) have Pm 3 longer than or subequal to Pm 4, never shorter, with the sole possible exception of O. (O.) wetterensis Brundin, 1956 . The color of the vittae is variable, winter specimens are often black, while spring specimens are lighter.

The RBINS males examined are in poor condition, the color of the vittae was not registered in the pinned specimens and cannot be evaluated in the mounted slide. Consequently, in light of the problems discussed in detail by SPIES & SAETHER (2004: 24‒26), the status of these two species ( O. rhycobius and O. rhyacophilus ) remains unresolved. In the present work, the solution proposed by ASHE & O’CONNOR (2012) is followed, considering Orthocladius (Orthocladius) rhyacophilous Kieffer, 1911 , a nomen dubium in Orthocladius .

Figures

Figs 53‒58. Orthocladius (Orthocladius) rhyacobius Kieffer, 1911. 53 ‒ antenna, 54 ‒ thorax, 55 ‒ palps, 56 ‒ hypopygium, 57 ‒ inferior volsella, 58 ‒ virga and superior volsella.