Family Cynipidae - Gall Wasps

Classification

Other Common Names

Gall wasps

Explanation of Names

Cynipidae Latreille 1802

Numbers

>750 species in ~50 genera in our area(1); >1400 described spp. in 74 genera total(2)

Identification

First segment of hind tarsi about as long as following two or three combined; most species humpbacked; abdomen with two segments visible dorsally, the remainder telescoped beneath.

Larvae always in closed cavities; larvae are never hairy (unlike in chalcids). Larvae of guest cynipids are not to be distinguished from those of the maker.(3)

Life Cycle

Succulent spring galls on oak buds, flowers, and leaves produce fully winged, short-lived males and females. The larvae in the more solid, autumnal galls metamorphose in the fall and depending on species the adults, which are all agamic females, may emerge in late fall (as in Disholcaspis spp.) or stay in the galls over the winter. Often two or more winters pass before the adults finally emerge.(3)

Remarks

It may be the normal reaction of the host to the stimulus of a cynipid or it may be quite abnormal if it has been modified in size and structure by the attack of guests or parasites in its early stages. Only if found in numbers and on several trees is it probably the characteristic work of a cynipid and worth collecting and rearing.(3)

Internet References

Gallformers: An very useful resource for gall study...species pages include excerpts and reference images from the literature, and bibliographic info.

Works Cited