A study of Tetraneura Hartig, 1841 (Homoptera, Aphididae), with descriptions of a new subgenus and new species

Abstract

When soon after World War II a compatriot handed me some aphids taken from a gall on Ulmus in France it appeared that they could not be identified with the existing literature. The very large claws of the embryos in the alatae were also known from Tetraneura hirsuta (Baker ), now T. nigriabdominalis (Sasaki), and the French material was identified as T. hirsuta. Later similar material carne in from Yougoslavia, Hungary and Russia. But T. hirsuta had never been found on grass roots in Europe. Therefore I searched for Tetraneura in Italy, and indeed found a grass root aphid which had embryos strongly resembling those in the French emigrants from Ulmus. However, the Italian aphids differed in some small characters from T. hir suta, and so did their embryos. Therefore experiments were made by my Hungarian and Russian colleagues, and the apterae produced by alatae from Ulmus galls were identical with the ones I found in Italy, much like T. hirsuta but just different. Then the search for the name began in earnest. Colleagues from many countries helped with mounted specimens, pickled samples from galls, or even full galls. I t appeared, as EA s TOP (1966) showed, that apterous exules of Tetraneura from grass roots can be distinguished by their morphology. But alatae can in many cases not be identified, certainly not by the characters used by MORDVILKO (1935). EASTOP (1966) published an excellent key to the alatae which he had. But evidently he could not separate species like the mentioned European Tetraneura from Ulmus, and Tetraneura hirsuta