498 
Saw-flies, Gall-flies, Ichneumons, 
ants, or cow-killers. The females (Figs. 699 and 700) are wingless and 
rather like ants in appearance, although readily distinguishable from them 
by their covering of white, red, black, or golden hair and of course by the 
absence of the scale-like expansion of the basal abdominal segments char¬ 
acteristic of the true ants. The males are winged and much less frequently 
collected or seen. It is believed that all Mutillids 
live as guests or parasites in the nests of other wasps 
or bees. They are strong stingers and swift runners. 
Nearly two hundred species have been found in the 
United States, the center of abundance being in the 
southwest. They are common in California. Sphce- 
rophthalma calijornica (Pl. XII, Fig. 1) is J inch long, 
with brick-red hair, black on bases of abdomen and 
thorax; S. pacijica is similarly colored but much 
ma pacifica. (One and lar g er > i mch lon g; aureola, J inch long, has 
one-half times natural head, most of thorax, and posterior half of abdomen 
Slze, ' ) with yellow hair, elsewhere black. 
The brilliant metallic-green little bee-like cuckoo-flies (Chrysididae) 
are not unfamiliar to collectors, and belong, because of their habits, in the 
group of parasitic wasps. “Although these insects are handsome,” says 
Comstock, “they have very ugly morals, resembling those of the bird whose 
name has been applied to them. A cuckoo-fly seeks until it finds one of 
the digger-wasps, or a solitary true wasp, or a solitary bee, building a nest, 
and when the owner of the nest is off collecting provisions steals in and lays 
its egg, which the unconscious owner walls in with her own egg. Some¬ 
times the cuckoo-fly larva eats the rightful occupant of the nest, and some¬ 
times starves it by eating up the food provided for it. The bees and wasps 
know this foe very well, and tender it so warm a reception that the brilliant- 
coated little rascal has reason enough to double itself up so that the righteous 
sting of its assailant can find no hole in its armor. There is one instance on 
record where an outraged wasp, unable to sting one of the cuckoo-flies to 
death, gnawed off her wings and pitched her out on the ground. But the 
undaunted invader waited until the wasp departed for provisions, and then 
crawled up the post and laid her egg in the nest before she died.” 
Of mason- or potter-wasps, that is, solitary wasps that make a nest of 
clay or mud worked up with saliva, there are numerous species belonging 
to several different families. The daintiest mud-nests are the little vases 
of Eumenes (Fig. 701), which are said to have served as models for early 
Indian pottery. Eumenes is a neat little black-and-yellow wasp with the 
abdomen shaped like an old-fashioned tear-drop earring. It belongs to the 
family Eumenidae, which is the only family of solitary wasps (besides the 
rarely seen parasitic Masaridse) which fold their front wings longitudinally 
