Strongylogaster, Dahlbom, 1835

Macek, Jan, 2010, Taxonomy, distribution and biology of selected European Dinax, Strongylogaster and Taxonus species (Hymenoptera: Symphyta), Acta Entomologica Musei Nationalis Pragae 50 (1), pp. 253-271 : 264-265

Key to sawfly larvae associated with ferns in the Czech Republic with emphasis on Strongylogaster

1 Endophagous, mining in fern axis. ............................................................................. 2

– Exophagous, feeding on fern fronds. .......................................................................... 3

2(1) Mine in fern axis short and straight with two openings; rear opening with a mass of froth-like spittle. .......................... Blasticotoma filiceti Klug, 1834 (Blasticotomidae)

– Mine in fern axis long, with one opening, descending down and upwards causing leaf malformation and crumpling; without froth-like spittle. ............................................... ................ Heptamelus ochroleucus (Stephens, 1835) ( Tenthredinidae : Selandriinae )

3(1) Abdominal segments with six annulets. ..................................................................... 4

– Abdominal segments with seven annulets. ................................................................. 5

4(3) Ground colour of body uniformly green. Host plant: Athyrium . ................................... .......... Strongylogaster macula (Klug, 1817) ( Tenthredinidae : Selandriinae ) ( Fig. 10 )

– Ground colour green, on dorsum finely mottled with slightly transparent dorsal blood vessel. Host plants: Dryopteris and Matteuccia . ........................................................... ..... Strongylogaster baikalensis Naito, 1990 ( Tenthredinidae : Selandriinae ) ( Fig. 11 )

5(4) Annulets 2 and 4 with distinct white conical tubercles. ................................................ ......................... Tenthredo Linnaeus, 1758 ( Tenthredinidae : Tenthredininae ) (in part)

– Annulets 2 and 4 without or at most with indistinct conical tubercles. ...................... 6

6(5) Prolegs with fine scattered setae; body surface smooth. ................................................ .................. Aneugmenus Hartig, 1837 (three species) ( Tenthredinidae : Selandriinae )

– Prolegs bare; body surface granulose. ........................................................................ 7

7(6) Annulets with stiff setae on upraised warts. .................................................................. .................... Stromboceros delicatulus (Fallén, 1808) ( Tenthredinidae : Selandriinae )

– Annulets with tiny, short setae and without warts. ..................................................... 8

8(7) Ground colour grey, anal segment with black spot. Host plant: Athyrium . ................... ............ Strongylogaster mixta (Klug, 1817) ( Tenthredinidae : Selandriinae ) ( Fig. 12 )

– Ground colour green, anal segment without black spot. Host plant: Pteridium . ........ 9

9(8) Last larval instar with two black parietal spots on head. Larvae in May to June. ......... .. Strongylogaster multifasciata (Geoffroy, 1785) ( Tenthredinidae : Selandriinae ) ( Fig. 9 )

– Last larval instar with black upper half of the head. Larvae in June to early August. .. ..... Strongylogaster xanthocera (Stephens, 1835) ( Tenthredinidae : Selandriinae ) ( Fig. 8 )

Figures

Figs. 8–12. Strongylogaster Dahlbom, 1835, larvae: 8 – S. xanthocera (Stephens, 1835): a – immature instar (dorsal view); b – last instar (lateral view); c – last instar (laterodorsal view). 9 – S. multifasciata (Geoffroy, 1785): a – last instar (laterodorsal view); b – last instar (dorsal view). 10 – S. macula (Klug, 1817): last instar (laterodorsal view). 11 – S. baikalensis Naito, 1990: last instar (laterodorsal view). 12 – S. mixta (Klug, 1817): a – immature instar (laterodorsal view); b – last instar (lateral view); c – last instar (lateral view). Scale for last instar larva: 10 mm.