Observations on the nesting biology and behavior of Trypoxylon (Trypargilum) vagulum (Hymenoptera : Sphecidae) in Costa Rica

Trypoxylon (Trypargilum) vagulum Richards, a spider-hunting sphecid wasp, w as studied at the Organization for Tropical Studies' field station at La Se lva in Costa Rica. The wasps constructed nests in trap-nests with tube diam eters of 3.2, 4.8, and rarely 6.4 mm. Nest structure, cocoon morphology, an d differences between male and female provisions are discussed. Brood cells were provisioned with 7 to 35 spiders comprised mostly of juvenile snare-b uilding spiders of the families Araneidae, Tetragnathidae, Theridiidae, and Uloboridae. Prey also included a few juvenile Clubionidae, Ctenidae, and P isauridae. Natural enemies were Lepidophora trypoxylona Hall (Diptera: Bomb yliidae), Amobia erythura (Wulp) (Diptera: Sarcophagidae), Phalacrotophora punctiapex Borgmeier (Diptera: Phoridae), Macrosiagon lineare (Le Conte) (C oleoptera: Rhipiphoridae), Trichrysis nigropolita (Bishoff) (Hymenoptera: C hrysididae), and ants (Hymenoptera: Formicidae).