168 Zoology of Colorado 



but no mouth parts. They take no nourishment after reaching 

 the adult stage. In the case of the San Jose scale and its relations 

 (Diaspidae), the female secretes a waxy scale, under which it 

 lives, like an oyster in its shell. Other species form a scale con- 

 sisting of their own hardened bodies, still others envelop them- 

 selves in a dense covering of wax, while some mealy-bugs have 

 only a thin powdery secretion of wax on the surface of the body. 

 The wax scales are common in warm countries, but one species 

 (Ceroplastcs irregularis) comes as far north as Colorado, living 

 on the shrubby Atriplex canesccns. Small mealy-bugs, of several 

 genera, are very common under stones in nests of ants (Lasius). 

 They feed on roots of grass and other herbaceous plants, and are 

 carefully tended by the ants for their sweet secretions. When the 

 nest is disturbed, the ants carry the mealy bugs away into their 

 galleries for safety. To collect these ant-nest Coccidae, it is 

 necessary to examine the nests in the spring, for later in the year 

 both ants and coccidae have gone under ground, and are not easy 

 to find. One interesting species is the native cochineal (Dady- 

 lopius confusus). Masses of white material will be seen on 

 prickly-pear cactus (Opuntia), and when this is pulled apart, the 

 red stain of the insects themselves will be seen. Although this 

 is a true cochineal, it is not and never has been of any commercial 

 value, the insects being much too small to be worth gathering. A 

 common native species, which extends across the plains to Wray, 

 on the eastern border of Colorado, is Amonostherium lichtensioides, 

 forming round white sacs, on sage-brush (Artemisia). Narrow 

 white scales on leaves of pine trees in the foothills are Chionaspis 

 pinifoliae of Fitch. Lift one up with a pin, and the eggs will 

 often be seen beneath. Broader white scales on the bark of willow 

 and poplar are Chionaspis bruneri. The so-called oyster-shell 

 scale, better called mussel scale, is very small, dark brown, tapering 

 at the anterior end. It was introduced from the Old World, but 

 is widely spread in America. The name used for it is Lepidosaphes 

 ulmi (Linnaeus), but it has been shown by various workers, and 

 in great detail by Miss Grace H. Griswold in a recent (1925) 

 publication of Cornell University, that there are really two dis- 

 tinct forms. The form which particularly infests apple trees has a 

 uniform brown scale, but that found on lilac has the scale cross 

 banded with a paler color. The female insects themselves agree 



