498 Saw-flies, Gall-flies, Ichneumons, 



ants, or cow-killers. The females (Figs. 699 and 700) arc 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. Spha- 

 ro pit I hill III 11 calijornica (PL XII, Fig. i) is \ inch long, 

 with brick-red hair, black on bases of abdomen and 

 thorax; 5. pacifica is similarlv colored but much 

 ^«.";;;,^f'(ot''':nd larger, l inch long; 5. aureoia, i inch long, has 

 one-half times natural head, most of thorax, and posterior half of abdomen 

 ^'^^■^ with yellow hair, elsewhere black. 



The brilliant metallic green Uttle bee-like cuckoo-flies (Chrysididx-) 

 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 cats 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 rea.son 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. Eiunenes is a neat little black-and-yellow wasp with the 

 abdomen shaped like an old-fashioned tear-drop earring. It belongs to the 

 family Eumenida-, which is the only family of solitary wasps (besides the 

 rarely seen parasitic Masarida;) which fold their front wings longitudinally 



