Question: Today while
WASHING WINDOWS outdoors, I noticed THE strangest tunnels
yet. They are on a south facing brick wall, having a diameter
of almost 1/2". There are about 4 stuck side by side
and about 6" long. Some are soil color and some are
WHITE. They have about 20 holes in them and the openings
face downward. They are well over 6 ft above ground level.
They appear uninhabited.
Answer: These are the nests of Organ Pipe
Mud Daubers, in the genus Trypoxylon. These are common,
though harmless, wasps in Texas. The adults make the nests
as a rearing site for their young, whom they thoughtfully
provision with "fresh meat" in the form of paralyzed
spiders. The holes are where the newly emerged adult wasps
have emerged. The darker color tubes appear to be the most
To learn more, try a google search on organ pipe mud dauber.
These are good guys and will not attack you. Michael Merchant,
PhD, BCE; Urban Entomologist; Texas Cooperative Extension