109 



\,^ 



The Westekn Cai^jjage I-'lea-heetle. 



Phyllotretd jmailla Horn. 



(P. aUnotiica in error.) 



This species is included among the less important corn insects because 

 of Its injuries to corn in Nebraska in 1897. It appeared locally in swarms 

 like black clouds, covering garden anri other plants, and destroying from 

 ten to twenty acres of corn on oik; farm in twenty-four hours. The 

 beetle (Fig. 90) is only about a fifteenth of an inch long, uniform deep 

 polished green above, and without stripes. It is 

 most destructive to cabbage and other cruciferous 

 plants, but it is also known to injure peas and 

 sugar-beets. Its immature stages are unknown. 

 Beetles noticed late in June disappeared about a 

 month later. The species is foimd from the 

 Dakotas trj Mexico and thence to the Pacific coast. 



The Corn Flea-beetle. 



Chxtocnema pulicaria Mels. 



This minute bronzed species seems quite partial 

 to corn leaves, and is in some years abundant 

 enough in Illinois to check the growth of young 

 plants, and occasionally to destroy them by riddling the leaves with 

 muiute holes. The beetle (Fig. 91; PI. VII., Fig 2) is less thar. a 

 twentieth of an inch in length, oblong-oval, shining greenish-bron.e 

 above, except the thorax, which is notably dull. It feeds on the 

 under side <>i the leaf, usually leaving the upper epidermis unbroken, 

 but sometimes eating through the blade. The 

 stalk is also occasionally injured. 



In various years, but especially in 1891, re- 

 ports of marked ijijnry to corn by this flea- 

 beetle came U) us from many Illinois locali- 

 ties, in twelve different counties. About Jack- 

 sonville it ai>peared in corn fields within a 

 radius of thirty miles from town. Whole 

 fields were wilted more or le.ss, and some hills 

 entirely killed. As many as forty beetles were 

 counted on one hill. An infested field near 

 Manchester, in Scott covmty, was visited by an 

 assistant July 19, 1892. The beetks were quite abundant in it, and 

 the corn was very small (not over ten inches high) and pale and 

 unhealthy looking. In 1891 similar injuries were recorded in Mis.souri 



I'lo. 90. The Western 

 Cabbage Flea-beetle, Phyl- 

 lotreta allnonica. lOriiarge'J 

 as indicate' I. (Riley, U.S. 

 Dept. of Agriculture.) 



Fi<;. 91. The Corn Flea- 

 beetle. CfujElocnema puii- 

 cana. Length about one 

 twentieth inch. 



