Numbers
with ~50 spp. in 6 recognized subgenera in our area, the largest pompilid genus in NA; close to 300 spp. total
Size
12‒20 mm, a few >30 mm in our area
Identification
black wasps, often with orange abdominal markings. Females have noticeable stiff bristles on pygidium. Identification of males often difficult.
Season
Late spring to early autumn
Food
Larvae provisioned with wolf spiders, funnel web spiders. Many are generalists. A. marginatus has been recorded taking Opiliones
Life Cycle
Some have several generations per year starting late May. Females of A. tenebrosus overwinter and can be found as early as April in the southern part of range.
Remarks
Most are fossorial ground nesters, although some will use borings in wood and other crevices.
See Also
Arachnospila is very similar. Good views of the pygidium help but it is much safer to identify them on the basis of characters seen through a microscope.
Print References
Evans H.E. (1951) A taxonomic study of the nearctic spider wasps belonging to the tribe Pompilini, Part II. Trans. Amer. Ent. Soc. 76: 207‒361 (
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