Rolf Nussbaumer / Black and yellow Mud Dauber (Sceliphron caementarium) female collecting mud for her nest. Comal County, Hill Country, Central Texas, USA, July.

Stephen Dalton / Mud dauber wasp (Sceliphron caementarium) flying over cactus spines, Everglades NP, Florida, USA

John Abbott / Blue mud wasp (Chalybion californicum) Bastrop County, Texas, USA. May

Clay Bolt / Blue Mud Dauber Wasp (Chalybion californicum) on Mountain sweet pitcher plant (Sarracenia rubra jonesii) Cataract Bog, Southern Appalachians, South Carolina, USA, September.

Clay Bolt / Blue Mud Dauber Wasp (Chalybion californicum) on Mountain sweet pitcher plant (Sarracenia rubra jonesii) Cataract Bog, Southern Appalachians, South Carolina, USA, September.

MYN / Pierre Escoubas / Black and yellow mud dauber (Sceliphron caementarium) Corsica, June. Meetyourneighbours.net project.

Michael Durham / Black and yellow mud dauber wasp (Sceliphron caementarium) in flight, captive, July.

Rolf Nussbaumer / Blue mud dauber wasp (Chalybion californicum) adult in flight among Old man's beard (Clematis drummondii) flowers, Dinero, Lake Corpus Christi, South Texas, USA.

Nick Upton / Blue mud dauber wasp (Chalybion sp) feeding on Rock samphire / Sea fennel (Crithmum maritimum) Samos, Greece, August.

John Abbott / Blueberry / Mason bee (Osmia ribifloris) flying to its nest in an old Trypoxylon mud dauber wasp nest, Texas, USA, March

John Abbott / Blueberry / Mason bee (Osmia ribifloris) flying to its nest in an old Trypoxylon mud dauber wasp nest, Austin, Texas, USA, March

John Abbott / Blueberry / Mason bee (Osmia ribifloris) on old nest of Trypoxylon mud dauber wasp with Sapygid wasp (Sapyga nevadica) flying in to parasitize the bee, Texas, USA, March