THe HyMenoprera OF MINNESOTA 221 
bees, the legs of these wasps are adapted only for digging and walk- 
ing. They love the sunshine and move actively about in the heat. 
Provided with a powerful sting, they are enabled to paralyze their prey 
(insects) by stinging the principal nerve ganglia. Their victims stored 
in their nests as food for their larvae, live many days but are incap- 
Fig. 110. Pseudoplisus phaleratus Say. 
_able of movement which would endanger the life of the sphecid egg or 
larva. Caterpillars so stung may transform to pupae but are too weak 
to carry the transformation further. Members of this family either 
make nests in sand or act as “mud daubers,” building their cells of mud 
and plastering them on walls. 
Ammophila (Sphex) is a genus of giants. Many of them prey 
upon the large Cicadas or harvest flies, easily carrying them off to 
‘great golden dig- 
‘ 
their nests. S. ichneuwmon sometimes called the 
ger,” isa common form in the United States. Packard reports seeing in 
late summer or early autumn nearly a dozen of these wasps engaged in 
digging holes in a gravelly walk. These holes were from four to six 
inches deep. 
This genus also preys upon crickets. These insects, tho paralyzed, 
survive for several weeks (Fabr.). Three or four crickets are some- 
times found in each cell and a single Sphex may destroy one hundred 
or more crickets in this way. The egg is placed on ventral surface of 
victim between 2nd and 3rd pairs of legs, and hatches in three or four 
days. In six or seven days, the larval Sphex has completely eaten out 
the insides of the cricket, and it then attacks another. In ten or twelve 
days the stock of crickets is exhausted. 
S. W. Williston reports (Ent. News Vol. III p. 85), that Ammo- 
phila (Sphex) yarrowi Cr. has been observed to bury four or five 
caterpillars, storing them in her burrow for food of her future off- 
