abstract:The Trigonalidae (sometimes spelled Trigonalyidae but the former spelling has formal precedence; see the Trigonalidae Website) are one of the more unusual families of hymenopteran insects, of indeterminate affinity within the suborder Apocrita (though sometimes believed to be related to the Evanioidea), and presently placed in its own superfamily, Trigonaloidea. Trigonalidae is divided into two subfamilies, Orthogonalinae and Trigonalinae.