Definition of "infumation"

The conspicuous dark maculation of the otherwise light tegmina and the feeble infumation of the apex of the wings, with the nearly uniformly colored dorsum of the prothorax and the relatively small size, are the distinctive marks of Duncan Island forms.

1895, Bulletin of the Museum of Comparative Zoology, page 14

I am sure Frederick Smith has correctly named a pair in the British Museum, with the whole upper and to a less extend the lower basal cells infumate and the apical alar infumation approaching closely to the stigma; one probably came from Bates and the female, which lacks the single black marks on the second and third segments, was acquired about 1839 through Mr. Mornay from Brazil.

1915, ‎Claude Morley, A Revision of the Ichneumonidae Based on the Collection in the British Museum, page 20

The character and the degree of infumation is of value in the separation of species.

1917, John Bernard Parker, A Revision of the Bembicine Wasps of America North of Mexico, page 58