318 
HALF HOURS WITH INSECTS. [Packard. 
typical example is the Sphex (Fig. 59) whose habits have 
already been described. The mud dauber (Pelopceus Jlavi- 
pes) is a slender form, brightly banded and spotted with 
yellow, and is found all over the country. Her cells of pel¬ 
lets of mud plastered on the wall of a house are common 
objects known to every school boy* These cells are built 
of layers of mud of unequal length, the pellets being placed 
in two rows, diverging from the middle. They are a little 
over an inch in length and about half as wide, and are seen 
in section to be triangular in outline. The larva within 
spins a brown silken cocoon, after eating up the store of 
paralyzed spiders, whose remains may often be found tucked 
away at one end of the cell. Several cells usually occur 
together, covered over with a common layer of mud. 
This habit of collecting materials for their nests is shown 
more distinctly in the black Sphex ( S . tibialis) which forms 
its nest in the tunnels previously made by the carpenter bee 
in a piece of pine board. In an example described in my 
“Guide to the Study of Insects,” the hole was six inches 
long, and the oval, cylindrical cocoons were packed loosely, 
either side by side, where there was room, or in a single 
row. The interstices between them were filled with bits of 
rope, which appeared as if they had been bitten in pieces by 
the wasp itself, while the end of the cell was filled for a dis¬ 
tance of two inches with a coarse sedge arranged in layers, 
as if rammed in like gun wadding. 
Another exception to the burrowing habits of the sand 
wasps is afforded by a Brazilian species of Larrada, which, 
according to Mr. Bates, builds a nest “ composed apparently 
of the scrapings of the woolly texture of plants; it is at¬ 
tached to a leaf, having a close resemblance to a piece of 
German tinder, or a piece of sponge.” In thus availing 
itself of the scrapings of the bark of plants, we have a 
slight anticipation of the paper-making wasps. The wood 
wasps evince fully as much, if not more, architectural skill 
30 
