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Species guide - species detail

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Passaloecus cuspidatus (aphid wasp/square headed wasp)



Passaloecus are aphid wasps in the family Crabronidae. They are known for their large mandibles in which they carry prey back to their nests. These mandibles are also used in clearing debris out of nesting sites. In Minnesota, the genera represented inhabit the Holarctic and Nearctic regions. P. cuspidatus is considered to be in the corniger group of species.


Passaloecus cuspidatus are some of the larger species of Passaloecus, reaching up to 9mm in length. They have black bodies with appendages ranging from amber to creamy yellow. Two characteristics that set P. cuspidatus apart from others are a strongly tridentate clypeal lobe and a scrobal sulcus that is very weakly impressed. Female P. cuspidatus wasps have bidentate, strongly curved mandibles while males have shorter, sharper bidentate mandibles.

Nest Structure

Passaloecus cuspidatus build their nests in the stems of plants – most commonly in the stems of American Elderberry and lilacs. They are also known to inhabit abandoned beetle galleries or, in the case of the Minnesota Bee Atlas, holes in wood blocks. P. cuspidatus partition these cells with resin and provision them with aphids.

Hole Sizes

No information at this time.


This species appears to be univoltine throughout its range, completing one generation per year in Minnesota.

Activity Period

Passaloecus cuspidatus are active in Minnesota from April to September.


Vincent, D. L. 1973. A revision of the genus Passaloecus (Hymenoptera: Sphecidae) in America north of Mexico. The Wasmann Journal of Biology, 36(1 & 2): 127-198.

Minnesota Record Map

These data are from the Minnesota Bee Atlas project.

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