Catalpa
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Discolored, circular leaf spot...Neolasioptera sp.

Spots are about 5 mm in diameter and can be found from May to November...Some larvae drop to the ground to pupate, other pupate in the leaf. Adults were reared in spring from galls collected in November. Host: C. bignonioides...

After the larvae disappear from the leaves, the resemblance of these spots to some of the fungous leaf-spot maladies is so great that for one or two seasons our botanists examined the spots very carefully at intervals with the compound microscope, the only result being to strengthen the suspicion that they were in some way caused by insects...
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[Not totally clear from the description that this damage is actually a gall, but at least some instances probably are if they are indeed induced by a Neolasioptera sp. Gossard assigned these to Contarinia ['Cecidomyia'] catalpae, but only provisionally.]