Euura piliserra (Thomson, 1863) : Benes, 2015

Liston, Andrew D., Heibo, Erik, Prous, Marko, Vårdal, Hege, Nyman, Tommi & Vikberg, Veli, 2017, North European gall-inducing Euura sawflies (Hymenoptera, Tenthredinidae, Nematinae), Zootaxa 4302 (1), pp. 1-115 : 82

E. piliserra group

Diagnosis. Adult. In lateral view right mandible gradually tapering, left one with swollen base and thin, blade-like apex. Vein 2r-m normally present in both fore wings. Supraclypeal area densely setose. Antenna long: in female longer than fore wing costa, in male longer than combined length of costa and pterostigma. Valvula 3 in dorsal view nearly parallel-sided basally, or slightly bulbous, with abruptly tapered apex; in lateral view not emarginate, or scarcely so, on either margin. Metatarsomere 4 dorsally shorter than its apical width. Lancet: very broad; annular sutures strongly arcuate. Penis valve: ventrally without small spines; base of valvispina ventrally not clearly divided from lobe on which it arises.

Larva. Third abdominal segment with 4 dorsal annulets; 1–3 with setae. Suranal plate without pseudocerci.

Gall. Each side of leaf-blade rolled downwards and meeting below the midvein, so forming a tube in which several larvae live: usually 3–5, but sometimes up to 8). At first they eat the lower epidermis and parenchyma, leaving the upper epidermis intact. Later instars leave the roll and eat the leaf-blade from the tip, leaving the midrib intact. Oviposition in the underside of leaf-blade, between midrib and edge ( Lorenz & Kraus 1957).

Phenology. Bivoltine according to Benson (1958) and Beneš (1968a).