Acroceridae is a family of spider-parasitic flies that often visit flowers as adults, although little is known about their possible role as pollinators. Eulonchus tristis Loew visiting flowers of Brodiaea elegans Hoover (Liliaceae s.l.) and Iris douglasiana Herbert (Iridaceae) were collected in California. Individuals carried large pollen loads, although visitors to B. elegans carried significantly more pollen grains than visitors to I. douglasiana. Visitors to B. elegans also carried a higher percentage of focal-plant pollen (91%) than visitors to I. douglasiana (38%). There was no difference in the diversity of pollen species (approximately nine) carried by visitors to either plant species. For visitors to B. elegans, no difference was seen in the amount or diversity of pollen carried with respect to the sex of the visitor. The behaviour potentially resulting in the acquisition of these pollen loads is discussed. These results show that E. tristis has the potential to be an important pollinator for these plant species, particularly B. elegans.

Trypoxylon (Trypargilum) tridentatum tridentatum Packard (Hymenoptera: Crabronidae) is a spider-hunting wasp in mesic and xeric habitats in the arid Baja California peninsula of Mexico. Spider (Araneae) prey were collected every 2 weeks from wasp trap nests. Individuals of the family Araneidae were the most abundant prey (60.9%), followed by Theridiidae and Mimetidae. Dictynidae, Anyphaenidae, Salticidae, Uloboridae, Tetragnathidae, Miturgidae, and Philodromidae were captured only in the mesic habitat. An unidentified species of Eriophora Simon (Araneidae) was the most frequently collected spider in the xeric habitat (29.0%), followed by Theridion submissum Gertsch and Davis (Theridiidae) (24.0%), which was the commonest prey species in the mesic habitat (21.1%), and Metepeira crassipes Chamberlin and Ivie (Araneidae) (16.5%). Nineteen species and three families are newly recorded as prey. The araneids Araneus lineatipes (O.P.-Cambridge) and Kaira alba (Hentz) and the uloborids Philoponella arizonica (Gertsch) and Uloborus segregatus Gertsch are new records for Baja California.