499 
Wasps, Bees, and Ants 
as the social wasps (yellow-jackets and hornets) do. In this family are 
found diggers, and miners in the earth, carpenters making their nests in 
twigs or boards, as well as masons or clay-handlers. The species of the 
genus Odynerus are numerous; in appearance they resemble the yellow- 
jackets, but are smaller and more slender. They are given to taking advan¬ 
tage of any deserted nest of another wasp, or of some already existing hole 
or tunnel, to save themselves the trouble of mining or moulding a nest of their 
own. Riley found an Odynerus cell in the tunnel through a spool, and Ash- 
mead found one in the keyhole of a door-lock. The familiar, long, thread- 
Fig. 701. Fig. 702. 
Fig. 701.—A vase mud-nest of Eumenes sp. (Natural size.) 
Fig. 702.—Nest of a mud-dauber wasp. (Natural size.) 
waisted, nervous, black-and-yellow or steel-blue mud-daubers that build 
several tubular cells an inch or more long side by side of mud, plastered to 
the under side of a porch roof, on ceilings, under eaves, or under flat stones, 
belong to the genus Pelopceus (PI. XII, Fig. 15) of the large family Sphe- 
cidae. These cells are provisioned with paralyzed or dead spiders. Another 
smaller kind of mud-dauber is Agenius, a genus of the Pompilidiae. The 
tiny mud-cells of these wasps, built in crevices or on stones, are also pro¬ 
visioned with little spiders, often with their legs torn off. Originally the 
mud-daubers built their nests in hollow trees or under overhanging rocks, as 
they do yet sometimes; but they mostly nowadays take advantage of the safe 
and convenient places man arranges for them. 
Of Sharp’s fourth group, the true diggers or miners in the ground, I 
have already described a typical species in the Ammophila of the San Fran¬ 
cisco Bay salt marshes. There are many species of this genus, and they 
are found all over the country. The great golden digger, Sphex ichneu- 
