Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 63. (Budapest 1971)

Kovács, L.: Data to the knowledge of Hungarian Macrolepidoptera VI. Data with respect to migrating and spreading species

• F.0Map 8. Nycterosea obstipata F. — Annual mean of individual numbers caught by light traps The flight diagram of obstipata agrees to a great extent with that of the migrant species, lacking any definite phases. The presumption of ecological generations, overlapping each other, is in this case acceptable (Table 3). It can indubitably be inferred from the available phenological data that there is a considerable delay in its appearance from the west towards the north and the east. The earliest observations refer to the Transdanubia, occasionally already in April, the dates of the earliest collectings being: Keszthely, 21 April; Zalaerdőd, 23 April; Toponár, 25 April; Tolna, 26 April; and Szombathely 9 May. These dates still fall within the flight period of the first generation in the Adriatic seacoast, where the species indubitably breeds. The earliest observations concerning the Plains between the Danube and the Tisza were at Kunfehértó (10 May) and Tompa (19 May); those of the Trans-Tisza Region at Hódmezővásárhely (17 May), and in the eastern foothills of the Central Range at Miskolc (18 May). The species appears at the latest "in the northern part of the Transdanubia, the earliest datum for this area being 23 May (Budatétény). The delay measured to the earliest Transdanubian appearance is 19 days in the Trans-Tisza Region, 27 for the foothills of the Central Range, and 32 for the Northern Transdanubia. That its appearance seems to be gradually delayed northand southwards gives the illusion of the species arriving from the west and then advancing step by step towards the north and the east. However, certain considerations speak against this apparently uniform evolvement of the process. It should first be taken into account that obstipata regularly occurs also east and southeast of our borders (REBEL, 1911). Several specimens deriving from Transylvania and the southern part of the Bánság can be found also in the Collection of Lepidoptera of the Museum. Nor could the fact be disregarded that in certain years a more or less wide zone without a single observation separates the localities