56 o 
THE STUDY OF INSECTS . 
keyholes in our house, including those in the bureaus ; thus 
constructing for us locks that required a good deal of time 
and industry on our part to open. Some species of Odyne - 
rus are masons constructing nests entirely of mud. One of 
our species makes a nest about the size of a hen’s egg. This 
is composed of hard clay, fastened to a twig of a bush, and 
contains many cells. 
Probably the most skilful of architects among our soli¬ 
tary wasps is Monobia quadndens (Mo-no^bi-a quadTi-dens), 
a species common in most of the states east of the Missis¬ 
sippi (Fig. 787). This insect bores a tunnel in solid wood. 
Figure 788 represents a nest in our collection which was 
made in a board in the side of a barn. The partitions are 
made of mud. Kach cell contained a pupa when the nest 
was opened ; so we do not know with what the nest was 
provisioned. 
Family VESPID.E (Ves'pi-dae). 
The Social Wasps . 
Here again, as with the ants, we find colonies consisting of 
three forms of individuals, males, females, and workers. The 
colonies exist for only one season ; the males and workers 
die in the autumn ; the females hibernate and each starts a 
new colony in the spring. In the early part of the season 
only workers are produced; later the males and females ap¬ 
pear. The three forms are similar in coloring. They are all 
winged, and the queens and workers are provided with ven¬ 
omous stings. The queens are larger than the workers, and 
the males have seven segments in the abdomen, while the 
others have only six. The male wasps do not sting, but they 
bear such a close resemblance to the belligerent, well-armed 
workers that this interesting bit of knowledge is entirely 
useless. When we see a hornet our interest in its sex hardly 
leads us to test it to see whether it will sting, or to examine 
it closely to ascertain if it has seven abdominal segments. 
If male wasps wish to get any credit for their amiability, 
