New species of parasitoid that attacks walnut twig beetle, Pityophthorus juglandis Blackman (Coleoptera: Curculionidae: Scolytinae)

A new species of Theocolax Westwood (Hymenoptera, Pteromalidae, Cerocephalinae) is described from the United States and is one of only three species of Theocolax to be documented in North America.  This new species of Theocolax has been reared from the Walnut Twig Beetle (Pityophthorus juglandis Blackman) which transmits Thousand Cankers Disease.  The wasp is characterized by these morphological traits: a tuft of setae at the apex of the submarginal vein, a patch of horizontal striations on the pronotal side, the post marginal vein being subequal in length to the stigmal vein, the interantennal lamella extending more than half way to the median ocellus, and a large macula behind the stigma vein of the forewing.  Sequences of CO1 have been deposited in GenBank for adults of the new parasitoid as well as the other Theocolax currently found in the United States.  Obtaining sequence data from Theocolax wasps proved difficult and all attempts at sequencing CO1 from the larvae have failed. The new parasitoid has so far been reared from the Walnut Twig Beetle in both Colorado and Tennessee.