No. 6. DEPARTMENT OF AGRICUI.TURE. 537 



terial is exhausted before proceeding to another place to repeat the 

 operation."— (Prof. J. B. Smith.) 



It is remarkable as being the only herbivorous Lady-bug. All 

 other species are insectivorous and beneficial. In both the larval 

 and adult stages it feeds on the leaves of nearly all the cucurbits, 

 and pupates while attached to the leaves. 



It is killed by applications of any of the arsenites, the same as are 

 the other Coleoptera or beetles here discussed, and is likewise pre- 

 vented by covering the plants. It is killed under the paper tent, 

 Mechanical Device No. 2. 



ORDER COLEOPTERA: The Beetles. 



FAMILY CHRYSOMELID^: The Leaf Beetles. 



The 12-Spotted Cucumber Beetle {Diahrotica 12-notata.) Fig. 26. 



The adult of this insect is a greenish yellow beetle, with six black 

 dots on each wing-cover. It is very common on a great many kinds 

 of plants. The adult beetle feeds on foilage, and the larva feeds on 

 the roots of plants. It pupates in the ground and remains there 

 during the winter. There are tw'o brood® each year, the adults of 

 the second brood appearing during the first half of August. 



The eli'ects of this insect, the remedies to be employed, and the 

 enemies of this insect are the same as those of the next species. 



The Striped Cucumber Beetle {Diahrotica vittata.^ Fig. 27. 



This is one of the earliest and most destructive insects attacking 

 cucurbitaceous plants. It injures all species of plants of this family 

 as well as of some others. The beetles are about one-fourth of an 

 inch long and are yellow, with two black stripes extending length- 

 wise on each wing cover. 



They are too w^ell known to need detailed description. They ap- 

 pear on plants by the first of June, or as soon thereafter as the young 

 plants come above ground, and commence at once to eat ragged holes 

 into the leaves and even to chew off the young stems. (Fig. 28.) 

 They pair by the middle of June and continue breeding throughout 

 the summer, there being two distinct broods which overlap and are 

 thus indistinctly demarcated. In central Pennsylvania the second 

 brood commences to appear about the second week of August. The 

 adults feed on the leaves and tender vines and lay their eggs in the 

 ground. (Fig. 29.) The larvae feed on the roots and often cause the 

 plants to wither and die without apparent cause. (Fig. 30.) If the 



