8o 
STRANGE DWELLINGS. 
lengthened period, and after these members have served the 
purpose for which they were intended, they are broken off by 
the insect by means of a transverse seam near the base. There 
MYRMELEON. * AMPULEX. SCOLIA. 
are, however, many of the permanently winged hymenoptera, 
which possess very great powers of burrowing, and are able to 
excavate soil so hard that a knife can scarcely make its way 
through the solidly impacted mass of earth and stones. 
