Nerthra tuberculata (Montandon), an enigmatic species of toad bug (Heteroptera: Gelastocoridae), is redescribed, with a detailed description of its morphology, and novel information on its habitat. A discussion of its systematic position within Nerthra is provided, and it is placed in its own species-group.

Rhagovelia nigranota n. sp., is described from southern Mexico, and represents the first species in the robusta group to be recorded from that country. Figures of the male and female dorsal habitus and male genitalic structures are provided, accompanied by a distribution map.

The type species of Acolhua is discussed. The specimens considered to represent the type species Acolhua championi Distant by Slater & Brailovsky (1986) are shown to represent a previously undescribed species described as A. barrerai new species. The actual type species of Acolhua championi (Distant) is redescribed from Mexico.

Five new genera and five new species from New Guinea and New Britain are described, illustrated, and included in the tribe Colpurini. Base on the morphology of the female abdominal sternite VII the Colpurini is divided into two large groups, the first with plica and fissura include 22 genera and the second without plica and fissura include 20 genera, plus the five here described.

Males of the reduviid species Sinea diadema (F.) and S. confusa Caudell have so far been undistinguishable. The present light microscopy study revealed subtle differences in the parameres and more clear-cut differences in the genital capsules of the males of these two species. In addition, the eggs of S. confusa were studied using scanning electron microscopy. A comparison with published light microscopic observations on the eggs of S. diadema showed that the eggs of the two species differ as well. New locality records are given for S. diadema (U.S.A.: IA, TX), S. confusa (U.S.A.: PR; Mexico: Nayarit), S. defecta Stål (Mexico: Veracruz, Oaxaca, Chiapas), S. spinipes Stål (U.S.A.: CT, IA; Mexico: Vera Cruz), S. rileyi Montandon (U.S.A.: CT, WA), and S. complexa (U.S.A.: KS).

Additional distributional records are given and discussed for Thasus gigas (Klug), T. acutangulus (Stål), and T. neocalifornicus Brailovsky and Barrera. In particular, we emphasize the almost certain absence of T. neocalifornicus from New Mexico, and we discuss its population centers near Tucson, Arizona, and at the southern tip of Baja California Sur. Sinaloa and Chihuahua (Mexico) are new state records for T. gigas, and Chihuahua is a new state record for T. neocalifornicus.

Morphological caste differences and ovary conditions were analyzed in four colonies of Brachygastra augusti collected in different stages of the colony cycle. Differences between castes are distinct suggesting pre-imaginal determination. Many intermediates (non-inseminated ovary-developed females) were found. Because these intermediate females were morphologically similar to workers, it is suggested that they are young ovary-developed workers. Because there is a more evident overlap between queens and workers in the colony in pre-emergence of workers stage, and in three colonies in latter stages, especially in worker-production colonies, it is suggested that smaller queens are probably less viable than larger queens as observed in previously studied epiponines.