Oligosita Amerigana Ashmead Species Nova, a New Chalcidoid of the Fabily Trichogrammidae From Illinois

I xvE been requested to draw up the following description of a species of Trichogrammidae, which, though undescribed, has been mentioned in the literature for several years past, in fact as far back as 1903. It is the first species of the genus Oligosita Haliday (Walker) to be described from North America and is parasitic on jassid eggs, as will be shown later. In 1903, Professor F. M:. Webster published a brief paper entitled Some Insects Inhabitants of the Stems of Elymus canadensis (Webster, 1903 a) in which it is stated in regard to this species: "*Oligosita americana Ashmead MS. nov. sp. Also reared from same species of grasses from Princeton, Ind., and in connection with Eurytomocharis eragrostidis Howard, at Urbana. This is the first time this genus has been recorded in America." The species is marked with an asterisk to show that it also was reared from Elymus virginicus and the original rearings were made at Urbana and Champaign, Illinois, in connection with studies on species of Isosoma inhabiting the stems of various grains and grasses. In this way, the parasite became connected with Isosoma as host, and in the same year, Webster (1903 b) recorded it definitely from the eggs of Isosoma hordei (Harris) in these words: "There is little doubt that Oligosita americana Ashm. and Polyneura citripes Ashm. both attack and destroy the eggs, as I have reared them in numbers from stems of Elymus inhabited by the larvae, and also the stems of other grasses inhabited by other Isosoma larvae." (p. 33). Webster adds further, in connection with Isosoma grande (Riley), "not with certainty from Isosoma grande Riley," and also he indicates it to be an egg-parasite of Isosoma tritici (Fitch) and I. captivum Howard. The hosts of the parasite were therefore listed in accordance with the foregoing by Girault (1907). So far as I am able to find, it has not been mentioned again in the literature. Recently, I have been informed by Mr. R. :L. Webster of Ames, Iowa, who reared the species at Urbana, Illinois in 1905 from the eggs of a jassid determined by Herbert Osborn as being those probably of Dorycephalus platyrhynchus Osborn, that its previous record from the eggs of species of Isosoma by the elder Webster (1903;