Technical Abstract: Gall midge insect species cause economic threshold loss on cereal crops worldwide and the family Cecidomyiidae makes up the sixth largest group of Dipteran insects. The most important of these pests include the Hessian fly, Mayetiola destructor; the Asian rice gall midge, Orseolia oryzae; and the wheat midge, Sitodiplosis mosellana. The majority of gall midges are obligate plant parasites that cause the formation of galls on their host plants. Thus, the species diversity of this group is thought to be associated with its capacity to genetically adapt to different hosts. Further, because the salivary fluids are the primary mechanism whereby these insects interact with their host plants, the genes expressed in the cells of the salivary glands are expected to reflect this capacity for genetic adaptation. A preliminary comparative analysis between these species revealed homologs that were shared amongst all three species and between any two of the species. Further, there were a number of tentative unique genes (TUGs) restricted to each species and classified as novel with a secretory signal peptide. These results should provide clues to the molecular mechanism(s) involved in the adaptation of these gall midges.