ANNALES HISTORIGO-NATURALES MUSEI NATIONALIS HUNGARICI Tomus 54. PARS ZOOLOGICA 1962.

Micronecta minutissima (L.) (Heteroptera, Corixidae) a new species for Hungary

By A. W R Ó B L E W S K I , Poznan*

In a recent paper of mine ( W R Ó B L E W S K I , I960), the result of a study of the material kept in the Természettudományi Múzeum in Budapest, I have stated the occurrence in Hungary of only four species of Micronecta K I R K . , namely M. pusilla H O R V . , M. meridionalis (COSTA), M. griseola H O R V . and M. poweri ( D G L . SC . ) . Al l others recorded for this country by H O R V Á T H (1916) proved to be merely their synonyms. And so the specimens identified by this author as M. minutissima (L.) belong, in reality, partly to M. poweri ( D G L . S C . ) , partly to M. griseola H O R V .

As to the geographical distribution of M. minutissima (L.), my primary supposition ( W R Ó B L E W S K I , 1958) was that this mainly lacustrine species is restricted to the more northern parts of Europe and does not transgress the barrier of the Sudethian and Carpathian Mountains. Nevertheless, since I found it in Czechoslovakia near Prague and also in the material from the vicinity of Brno, its occurrence in Hungary turned out to be more probable.

When in June 1961 I was given opportunity to visit Hungary and to collect there personally, I tried first of all to find M. minutissima (L.), and also M. car-pan'ca W R Ó B L . , whose presence in the north-eastern region of this country seemed still more likely. Owing to the friendly help of Dr. A. Soós and thanks to the eid of the Hungarian Academy of Sciences, I was able to undertake several collecting trips to the Mecsek, Bükk and Zemplén Mountains, then to the Tata waters and to the Lake Balaton. I t wras in the Mts. Bükk that I succeeded to find M. minutissima (L.).

Lillafüred, the reservoir on the Garadna brook, near its inflow. NE bank grown with alders and shrubs, muddly bottom covered with dead leaves, 19. V I . 1961, 13 a* 8 ? ? . The species was accompanied by M. meridionalis (COSTA) (35 o71

others, 665 specimens of Micronectae from 21 different stations), I have caught only one ? M. pusilla H O R V . in the Rony va rivulet at Végardó. The species seems to be absent also from the Balaton, though in my former paper ( W R Ó B L E W S K I , 1960) there were given 7 of its localities from this lake. Nor did J A C Z E W S K I (1934) find this species in the Balaton. I t is quite possible that M, pusilla H O R V . , reaching the westernmost points of its range in Hungary, is in regression, and i t is perhaps suppressed by M. meridionalis (COSTA) expanding from the West. This latter, in spite of its habits as known from elsewhere, lives in Hungary also in flowing waters. I collected most macropterous specimens in small rivers and rivulets.

Nevertheless, an experience of scarcely a fortnight is far from sufficient to warrant a final conclusion about the extinction of M. pusilla H O R V . I t is possible that the time was not proper and that just then there existed only eggs and larvae of the youngest instars which easily escape attention.

References: 1. H O R V Á T H , G.: Micronectae duae novae ex Hungária (Ann. Mus. Nat. Hung., 14, 1916, p. 501—503) . — 2. J A C Z E W S K I , T . : Notes on some Palaearctic Aquatic and Semi-Aquatic Heteroptera, chiefly from South-Eastern Europe (Ann. Mus. Zool. Pol., 10, 14, 1934, p. 2 6 7 - 2 8 8 ) . - 3. W R Ó B L E W S K I , A . : The Polish species of the genus Micronecta Ki rk . (Heteroptera, Corixidae) (Ann. Zool., 17, 10, 1958, p. 2 4 7 - 3 8 2 ) . - 4. W R Ó B L E W S K I , A . : Micronectinae (Heteroptera, Corixidae) of Hungary and of some adjacent countries (Acta Zool. Hung., 6, fasc, 3 - 4 , 1960, p. 4 3 9 - 4 5 8 ) .