On July 7, 1958, at Churchill Park, St. John's, a number of wasps were observed boring holes into the mortar between the bricks of a private dwelling. A total of 41 holes, three-sixteenths of an inch in diameter and up to three inches in depth, were counted. The majority of these holes faced south and a few faced west. Some were provisioned with small green caterpillars and capped, and others were in the process of excavation. This unusual nesting habit, and the presence of the wasps, caused much anxiety to the owner. One spraying with a five per cent DDT solution, concentrated in and around the holes, eliminated the infestation.