THE INSECT WORLD. 



217 



The genus Galeruca contains a series of rather small, oblong 

 species, mostly dirty clay-yellow in color, and more or less black 

 marked or spotted. Of these none is more troublesome than the 

 " elm-leaf beetle, " Galeruca xanthomelcsna, which is another of 

 our undesirable importations from Europe. It is rather greenish 

 yellow when fresh, with two black stripes on the wing-covers. 

 It hibernates as a beetle wherever it can find shelter, and attacks 

 the leaves of elms in spring as soon as they are well grown, 

 eating irregular round holes, so they soon look as if loads of 

 shot had been fired through them in every direction. The yel- 

 low, bottle-shaped eggs are laid in double rows on the under 

 sides of the leaves, and from them hatch the yellow, black-spotted 

 larvae, covered with little bristly tufts of hair. In the northern 

 part of its range, including the red shale of New Jersey, a single 

 brood is normal, but south of this, and including an extension 

 into Long Island, the insect has two broods annually, and at 

 Washington or further south may have three or even more. As 

 against these insects the arsenites are effective, and the trees 

 should be sprayed, preferably with the arsenate of lead, just as 

 soon as the beetles begin feeding. The object is to destroy as 

 many of the hibernating forms as possible, and to prevent egg- 

 laying in large part. A second spraying should be given when 

 the eggs begin hatching, to destroy the young larvae, and in 

 serious cases a third spraying a week or ten days thereafter will 

 be beneficial. When the larvae are full grown they descend the 

 trunk to the ground, where they change to bright-yellow pupae 

 among the grass or rubbish on the surface. Here they may be 

 destroyed by hot water, kerosene, strong soap-suds, lime, or 

 other suitable substances, and the second brood, where such 

 occurs, may thus be materially lessened. Where there are two 

 broods or more, repeated sprayings will be necessary, extending 

 throughout the summer. If these methods are generally adopted 

 the insect can be satisfactorily controlled. Protecting a few trees 

 - only among many that are neglected will always be difficult and 

 can be at best only partly successful.^ 



* For detailed information concerning the treatment of trees in cities 

 or towns, or on a large scale, the publications of the United States De- 

 partment of Agriculture and of the New Jersey Experiment Station 

 should be consulted. 



