INSECTS INJURIOUS TO BEETS AND SPINACH 305 



drical form, and the segments are strongly marked by rows of 

 raised tubercles, each of which bears a black hair at the tip. The 

 larvae become grown in late June and early July in Illinois, and 

 enter the earth to pupate, the beetles of the next generation 

 emerging about a month after the eggs were deposited. The beetles 

 of the second generation lay their eggs from July to September 

 and the beetles mature before winter sets in. In the District 

 of Columbia, Chittenden observes that the first generation is more 

 abundant on chick-weed and the second is injurious to beets and 

 spinach. 



Control. Thoroughly dusting or spraying the plants with 

 arsenate of lead will readily destroy the larvae and probably 

 most of the beetles. As in combating all flea-beetles the destruc- 

 tion of the weeds upon which they multiply is important. 



The Larger Beet Leaf-beetle * 



One of the principal pests of the sugar-beet in Colorado and 

 adjacent States is a rather large brownish leaf -beetle which with 

 its larvae destroy the foliage or so injure it that the plant dies. 

 It is often locally known as the " alkali bug " from the fact the 

 injury is mostly on alkali soil or land near it, and " french bug," 

 probably from the " frenching " of the foliage. The beetle is 

 from one-quarter to one-third inch long, and rather resembles 

 the elm leaf-beetle, varying from pale yellow to black, with the 

 wing-covers striped as shown in Fig. 258. Several wild plants, 

 including blites, Russian thistle, and saltbushf probably furnish 

 the normal food of the insect. 



" The beetles are gregarious, ' sometimes occurring in swarms 

 like blister-beetles.' Their brownish-gray eggs are deposited 

 in irregular masses, usually on the under sides of the leaves. 

 They hatch in about six days, and their larvae or young commence 

 feeding at once, continuing for nine or ten days, when they dig 

 their way into the ground, a few days later coming forth as beetles. 

 Although the beetles do much injury, the principal damage is 

 sometimes accomplished by the larvae, hundreds being found 

 on a single plant, which is either consumed or so injured that it 

 shrivels and dies. The larva, shown in the illustration, measures 



* Monoxia puncticollis Say. Family Chrysomelidce. 



t Dondia americana and D. depressa, Salsola tragus, and Atriplex argentea. 



