58 Bulletin of Zoological Nomenclature 48( 1 ) March 1 99 1 specialists on Crustacea without bringing significant benefit to taxonomy, as the genus Palaega seems to be quite obscure. (2) Niel L.Bruce Queensland Museum, P.O. Box 300, South Brisbane, Queensland 4101, Australia Palaega, as defined by the type species P. carteri Woodward, 1 870, is unambiguously distinct from Bathynomus. In all extant Bathynomus species the pleotelson posterior margin is truncate or subtruncate and provided with a number of distinct widely separated prominent spines. The pleotelson itself is always relatively short (about 0.67-0.86 as long as wide (Bruce, 1986)). In Palaega carteri the posterior margin of the pleotelson is smoothly curved or rounded and is finely serrate with a prominent median point; the pleotelson is nearly as long as wide (ratio 0.94, 0.95 (Woodward, 1870)). Wieder & Feldmann (1989) made a fundamental error in assuming that because Palaega goedertorum appeared indistinguishable from Bathynomus it followed that Bathynomus and Palaega were synonymous. Palaega, as constituted by the currently included species, is not a valid genus. Wieder & Feldmann (1989) themselves acknowl-edge that it is a form genus with representatives from several families. Species such as P. lamnae Bowman, 1971 and P. pumila Gall & Grauvogel, 1971 are not congeneric with the type species and could belong to different families. The diagnoses provided by Wieder & Feldmann are not congruent with contempor-ary diagnoses of extant isopod taxa and cannot therefore be applied to extant isopods. Their diagnosis to the cirolanidae effectively diagnoses only the Flabellifera. Similarly, their diagnosis for Palaega could be applied to several families. There is little utility in synonymising a precisely defined genus with a name that approximates to a group of families. In summary, it is my opinion that Palaega carteri Woodward is not congeneric with Bathynomus. Notwithstanding, some fossil isopods could well be species of Bathynomus. In order to maintain stability in the use o^ Bathynomus I strongly urge the Commission that, in all cases of conflict, Bathynomus be given precedence over Palaega and I therefore fully support the proposal of Martin & Kuck. Comment on the conservation of Semblis Fabricius, 1775 (Insecta, Trichoptera) by the designation of Phryganea phalaenoides Linnaeus, 1758 as the type species (Case 2655; see BZN 45: 275-277; Opinion 1596; see BZN 47: 154^155) I.M. Kerzhner Zoologicallnstitute, Academy of Sciences, Leningrad 199164, U.S.S.R. I should like to make a small correction to the history of this case; it does not aff"ect the ruhng. Hemerobius lutarius Linnaeus, 1758 was first designated as the type species oi Semblis Fabricius, 1775 by Blanchard in 1845 (p. 311), not [1848, p. 539] as stated on BZN 45: 275. Blanchard, C.E. 1845. Histoire des insectes, vol. 2. 524 pp. Didot, Paris.