The male genitalia of some primitive members of Enicocephalomorpha resemble those of primitive members of Euheteroptera. Other enicocephalomorphans share characteristics with certain auchenorrhynch homopterans. Assuming Enicocephalomorpha is holophyletic (the usual assumption), it is the sister group of Euheteroptera (all other heteropterans) and may represent a tenuous link with Auchenorrhyncha. However, Enicocephalomorpha may be paraphyletic; these 2 possibilities should be carefully explored. Three other aspects of heteropteran morphology are considered; the first abdominal sternum, abdominal and thoracic scent glands, and forewing structure and function. These, and the male genitalia, are briefly discussed as components of a heteropteran groundplan.