Trichogramma

The latest revision of this genus was published in 1960. Although it was a very great improvement over the 1918 revision, it left most workers unsatisfied. At present other revisional works are in progress, and new papers revising Trichogramma may be published at about the time this catalog appears. Several undescribed species from North America are at present known to be in manuscript. Fundamental studies are also currently being made on the genetics, hybridization, male genitalia, and biologies of the described species of Trichogramma. Consequently, the arrangement of the species in this catalog is provisional. ~Due to the fact that much of the older literature on biology cannot now be assigned to individual species as they are listed in this catalog, a large part of the biological literature on Trichogramma that was published before 1960 has been omitted. This literature is cited in full elsewhere; see Peck, 1963. Canad. Ent., Sup. 30: 51-73. ~Any species of this genus can be reared in the laboratory or insectary on the eggs of almost any convenient host, although Salt, 1938. Bul. Ent. Res. 29: 223-246 showed that a few insect eggs may be physically or chemically unsuitable. The true host specificity for Trichogramm in nature seems to be to appropriate insect eggs that are deposited in particular environmental niches rather than simply to the eggs of particular host species. Consequently, host species are not listed here for the species of Trichogramma, but their ecological requirements, as far as they are known, are indicated.