none Teratocytes (dissociated trophamnion cells liberated from eggs of certain hymenopteran endoparasites into host hemolymph upon hatch) from L. hesperus parasitized by P. stygicus or L. uniformis were analyzed and compared. Fatty acid profiles were similar in the 2 types of teratocytes except for myristic acid (C14.0) which was found in higher concentrations in P. stygicus and linolenic acid (C18:3) which was found in higher concentrations in L. uniformis. Of 22 amino acids found in both species, there were 12 that differed significantly between the 2 spp. (aspartic acid, threonine, alpha-aminoadipic acid, alanine, valine, isoleucine, leucine, tyrosine, phenylalanine, lysine, histidine and arginine). Most of these were essential amino acids, in every case, concentrations were higher in P. stygus than in L. uniformis associated teratocytes.