Meloidae, or blister beetles, from Guatemala collected by the authors, in the James Entomological Collection at Washington State University, and in the Colección de Artrópodos at the Universidad del Valle de Guatemala are recorded. New country records include: Pyrota tenuicostatis (Dugès, 1877), Epicauta (Epicauta) cinctipennis (Chevrolat, 1834), E. (E.) diana Pinto, 1991, Epicauta (Macrobasis) diversicornis (Haag-Rutenberg, 1880), E. (M.) forticornis (Haag-Rutenberg, 1880), E. (M.) isthmica Werner, 1949, Tetraonyx pectoralis Haag-Rutenberg, 1879, and Pseudozonitis vaurieae Enns, 1956. A case of human blistering caused by E. forticornis is recorded.

Se registran los Meloidae, o escarabajos ampolleros, de Guatemala colectados por los autores o en la Colección Entomológica James en la Universidad del Estado de Washington y en la Colección de Artrópodos de la Universidad del Valle de Guatemala. Especies que son nuevos registros para el país son: Pyrota tenuicostatis (Dugès, 1877), Epicauta (Epicauta) cinctipennis (Chevrolat, 1834), E. (E.) diana Pinto, 1991, Epicauta (Macrobasis) diversicornis (Haag-Rutenberg, 1880), E. (M.) forticornis (Haag-Rutenberg, 1880), E. (M.) isthmica Werner, 1949, Tetraonyx pectoralis Haag-Rutenberg, 1879, y Pseudozonitis vaurieae Enns, 1956. Se registra un caso de ampollos en humanos causadas por E. forticornis.

Diadasia diminuta (Cresson, 1878) (Apidae: Eucerinae: Emphorini) uses Sphaeralcea St. Hil. (Malvaceae) as its pollen host throughout much of its range in dry habitats of the western U.S. and Central America. Here we document a regional shift in pollen host and habitat. Based on observations of foraging behavior spanning 1–11 years at 17 study sites and analyses of scopal pollen loads collected at nest entrances, we show that D. diminuta relies almost exclusively on a rare, fire-following mallow, Iliamna latibracteata Wiggins (Malvaceae), as its pollen host in relatively mesic forest habitats of northwestern California and southwestern Oregon. The generalized flowers of I. latibracteata attract a wide array of visitors, but D. diminuta is likely the most important pollinator; it was present at 16 of 17 sites and accounted for at least 70% of visits in more than half of 52 site-year visitor surveys. Although D. diminuta is widespread and abundant across most of its range, we argue that the rare disjunct populations studied here may be genetically distinct and perhaps represent a case of incipient speciation, making them worthy of conservation concern.