Caryomyia striolacrustum (Hickory Midge Galls )

Caryomyia striolacrustum

Gagne Description ²

Common, on Eucarya hickories; on lower leaf surface between veins, usually clustered; height 2-3 mm, usually about as wide as long, basal half conical and deeply set into leaf swelling detectable on top surface of leaf as tan to black, conspicuous convexity, apical half of gall short-cylindrical with funnel-like, deep, narrow to wide concavity surrounded by correspondingly narrow to thick walls, center of funnel with short umbo; surface not sticky, yellow to brown, minutely longitudinally striated, the striations partly fibrous on distal half; gall often surrounded and occasionally partially covered by conspicuous, brown, irregularly shaped leaf exfoliation; larval chamber in basal half of gall, wall firm, thin basally, thicker distally than laterally, glabrous, with longitudinal ridges. The shape of the gall most closely resembles that of C. melicrustum but the surface of the latter is mucilaginous and smooth.

Gagne Biology Note ²

This gall appears to burst out of the leaf after it is mostly formed. In midJune in central Maryland new galls could be found in various stages of emergence from the leaf epidermis. These contained first instars. By mid-July to mid-August, fully emerged galls contained second instars or third instars.

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iNat Map

Carya	floridana, glabra, laciniosa, myristiciformis, ovata, pallida, texana, tomentosa
Texture	hairless
Alignment	erect
Detachable	no, yes
Location	between veins, lower leaf
Walls	thick, thin

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