502 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



wander about before entering the leaf in another place, If the 

 leaves are well sprayed with arsenate of lead many of the 

 larvae will be poisoned as they attempt to eat their way into the 

 leaf again. The adult insect is a small grayish moth with 

 minute dark spots on the front wings. 



The Cigarette-beetle (Lasioderma serricorne). This minute 

 brownish beetle, which is only about one-sixteenth of an inch 

 long, and its whitish grub or larva, feed on dried tobacco when- 

 ever they can find it. They do serious damage to the stored 

 dried leaves and to cigars and cigarettes after they have been 

 manufactured. In warm factories the insect may breed 

 throughout the year and increase in numbers very rapidly. 

 As this pest lives and breeds in any kind of dried tobacco it is 

 necessary to keep the factory clean and not allow fragments or 

 dust to collect in out of the way places. Infested tobacco or 

 tobacco products or infested factories may be fumigated with 

 carbon bisulphide or with hydrocyanic gas. 



There are several other insects that do more or less damage 

 to tobacco, but most of them can be controlled by keeping the 

 field and its immediate vicinity free from weeds, especially 

 those weeds that are nearly related to the tobacco plant, 

 or by spraying with arsenate of lead. 



GRASSES AND FORAGE PLANTS 



The Clover Root-borer (Hylastinus obsctirus} . The roots of 

 clover are often attacked by a short, thick, whitish larva that 

 feeds in the tap root or the larger rootlets. The adult insect is 

 a beetle only about one-eighth of an inch long and reddish- 

 brown in color. The beetles hibernate in the infested plants, 

 and early in the spring fly to new plants where they lay their 

 eggs. Badly infested fields should be plowed up as soon as the 

 crop is cut so that the roots may dry out and the larvae starve 

 before they are ready to pupate. This insect is seldom in- 

 jurious in pastures. 



The Alfalfa Weevil (Phytonomus murinus]. The alfalfa 

 weevil has recently been introduced into some of the western 

 states and threatens to become a serious pest. Both the larvae 



