Gall. -- Green, globular or somewhat elongate swellings on the stalk of marsh St. John's wort (Triadenum [Hypericum] virginicum). Length, 6-10 mm.; width, 5-5.50 mm.

The gall of this species is described as being subglobose and monothalmous, with a length of 1 cm. and diameter of 8 cm. The large irregular inner chamber is sur- rounded by rather thick walls, the outer part of which is soft and the inner part irregularly hardened and blackened.

Neolasioptera triadenii
Irregular stem swelling

Gall: Swellings are about 8-12 mm long and monothalamous.
The orange larvae overwinter in the stems and pupate there the following spring.

Host: Triadenum virginicum
Distr: MA, NY, NJ