Macrosiphoniella (Asterobium) herczeki sp. nov.-a new aphid species from Bulgaria (Hemiptera, Aphididae)

Here we present a description of a new aphid species from the subgenus Asterobium Hille Ris Lambers, 1938 of the genus Macrosiphoniella Del Guercio, 1911 in the tribe Macrosiphini Wilson, 1910 (Aphididae). The new species- Macrosiphiniella (Asterobium) herczeki sp. nov. living on Galatella villosa (Asteraceae) in Tolbuchin region, Bulgaria, is described based on apterous viviparous females. The new species is morphologically similar to M. (Asterobium) konyratica Kadyrbekov, 2018 from Kazakhstan from which it differs in several morphological and metric characters. We provided an updated key to "Blackman's & Eastop" online key to Aster-feeding aphids.