146 



BRANCH ARTHROPODA 



curiously enough, says Kellogg, " came to California in which state it has 

 done much more damage than elsewhere in our country from France, in- 

 troduced upon imported cuttings or roots " (Fig. 115). Probably not less 

 than 30,000 acres of vineyards have been destroyed by it since it was first 

 noticed in 1874. " The Phylloxera appears in four forms: (1) the gall 

 form, living in little galls on the leaves (Fig. 114), and capable of very 

 rapid multiplication (this form rarely appears in California); (2) the root 

 form (Fig. 115), which is derived from individuals which migrate from 

 the leaves to the roots, and which by the piercing of the roots, sucking the 

 sap, and producing little quickly decaying tubercles on the rootlets, does 

 the serious injury; (3) the winged form (Fig. 116), which flies to new vines 

 and vineyards and starts new colonies; and, finally, (4) the sexual forms, 



Fig. 116. Phyttoxe'ra vasta'trix: o, Migrating stage, winged adult; b, 

 pupa of same; c, mouth parts with thread-like sucking setae removed from 

 sheath; d and e, eggs showing characteristic sculpturing; all enlarged. 

 (Marlatt.) 



male and female (Fig. 117), which are the regenerating individuals, ap- 

 pearing after several agamic generations have been produced." The gall 

 stage may be omitted, and the individuals hatched from the fertilized eggs 

 go directly to the roots. The gall form can be prevented by spraying to 

 kill the winter eggs. But about the only real cure for the infested roots is 

 to dig them up and burn them and plant out resistant vines. The wild 

 vines of the Mississippi Valley have evolved with the Phylloxera, and are 

 capable of living and growing in spite of the pests. The French vine- 

 yards, as well as those of California, are being renewed by grafting French 

 stocks upon the resistant roots, thus rendering the vines practically im- 

 mune. There are many species of aphids, but this example must suffice for 

 our present work. 



Scale-bugs, mealy-bugs, and others (Coc'cidce) compose a very anomalous 



