Reference:
Andrietti, F., Casiraghi, M., Martinoli, A., Polidori, C., & Montresor, C., 2008. Nesting habits of two spider wasps: Anoplius infuscatus and Episyron sp.(Hymenoptera: Pompilidae), with a review of the literature. In Annales de la Société entomologique de France (Vol. 44, No. 1, pp. 93-111). Taylor & Francis Group.
URL:
https://www.researchgate.net/profile/Carlo-Polidori/publication/230785574_Nesting_habits_of_two_spider_wasps_Anoplius_infuscatus_and_Episyron_sp_Hymenoptera_Pompilidae_with_a_review_of_the_literature/links/09e415045c4ac60785000000/Nesting-habits-of-two-spider-wasps-Anoplius-infuscatus-and-Episyron-sp-Hymenoptera-Pompilidae-with-a-review-of-the-literature.pdf?origin=publication_detail