Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 59. (Budapest 1967)

Smit, F. G. A. M. ; Szabó, I.: The distribution of subspecies of Ctenophthalmus agyrtes in Hungary (Siphonaptera: Hystrichopsyllidae)

C. agyrtes kleinschmidtianus PETJS, 1950 — This east-European subspecies is found in the easternmost part of the country and we have seen it only from Tákos. C. agyrtes eurous JORDAN & ROTHSCHILD, 1912 — Hitherto only known from two localities in Romania (see Fig. 1), but material of this subspecies has now also been collected in Sarkadremete. Intergrades: The area of intergrades (hybrid forms) between two subspecies Fig. 3. Outlines of fixed process of clasper of four males of Ctenophthalmus agyrtes peusianus from Deszkáspuszta. Fig. 4. Aedeagal lamella of C. a. bosniens ï—^ C. a. peusianus from Kisnána can be quite wide (up to 50 km or so). It is not always easy to determine the status of specimens which are actually intermediate between two subspecies and a good deal depends on the interpretation and evaluation of the taxonomic characters by the individual taxonomist (who may be inclined or is forced to base his conclusions on insufficient material). Geographical considerations are usually significant, but e.g. in eastern Hungary it might still be almost impossible to decide whether a given form is intermediate between a. kleinschmidtianus and either a. peusianus or a. eurous as intergrades between these subspecies will very likely be extremely similar. As is usual in a zone of intergradation, one may find in one locality specimens which are typical or near-typical representatives of either of the constituent subspecies together with a variety of intergrades. Apart from these various forms one may of course also find specimens which are just plainly abnormal in varying degrees (as e.g. two males a. bosniens from Németbánya, ex Troglodytes troglodytes, are obviously somewhat abnormal ; 18 other males from the same locality, but from normal mammalian hosts, are quite normal — see Pig. 2). When more and more material becomes available to fill in the numerous lacunae in the distribution maps, general agreement may eventually be reached among students of Siphonaptera concerning the status of some populations which at the moment are presumably best regarded as hybrid populations. The following specimens indicate the existence of mixed populations: (a) The only male seen from Ócsa agrees on the whole with a. peusianus but the fixed process of the clasper as well as the aedeagal lamella show some signs of a. eurous influence, (b) Three males from Kisnána (in the Mátra-hegység) are normal a. peusianus but the fourth (collected together with one of the a. peusianus) is virtually a. bosniens except for the aedeagal lamella which has a touch of a. peusianus although the cuticular scales are coarse (Fig. 4). The occurrence of this specimen at Kisnána is extra-