BEETLES. 317 



po<lt;, etc., several are doubtless enemies of the Galeriica, though we have, as yet, no 

 proof of the fact. 3Iany hinls were observed on the trees infested by the beetles, but 

 tlie Enfrlish .spai-row, which was the most numerous, did not feed on the insect in any 

 stage of growth."' 



Very closely related to the numerous species of Gahriwa is Trirhabda. T. tomen- 

 tosa, a common insect on species of golden-rod {SoJidago) in the eastern United States, 

 is about 0.4 inch long, and of a dingy yellowisli brown with three dull, black longi- 

 tudinal strijies on tlie elytra, three lilack spots on the jirothorax, anil one on the 

 head. 



Priiliably few jierMins have failed to notice the small, yellow and black striped 

 beetles, J>iabrotica rittdtii, which swarm upon cucumber, squash, melon, and similar 

 vines, almost as soon as they apijiear aI)ove the ground. This beetle is 

 elongate-iival, about 0:1- inch long; the t'lytra are striate; the general 

 color is straw yellow with a l)lack strijie along the middle of each >» 



elytron, reaching from its base nearly to its tip and a stri]ie covering y * 

 the elytral suture; head, knees, tips of tibi:c, and tarsi arc black. The ^''"(Jro;;^^; ~,/„'it 

 daniaue, often considerable, which this beetle does to }oung cucumber 

 vines aViove ground is slight compareil with that which its larva does to the roots below 

 the surface nf the sdil. At the time when these beetles are swarming about the young 

 vines, they lay their eggs at or just below the surface of the ground on tlie stems of 

 the plants. These egus soon hatich, ami the larv;e feed upon or liore into the roots 

 and stems of the plants for nearly a month, when thej- ]jupate in a little nval cavity 

 which tliey form in the ground. Tlie piqial state lasts about two weeks. The larvrn 

 are slender, cylindrical, abciut 0.4 inch long, ami nearly white; their head is brownish, 

 and they have a lirownisli si)ot on the <lorsuni of the })osterior segment. This species 

 hibernates as imago, and is said to do so as jmiia; the ra])id growth of its larv.-i enables 

 it to have from two ti) three brodils each year. In earlv sjirinu', before cucumber vines 

 are out of the ground, these beetles attack pear, peach, and other lilossoms ; and I 

 have found them especially abuii<lant f>n the flowers of the shad-bush {Amelanrhief 

 canadensis). While the beetles eat a few cucumber plants, confining their attacks 

 entirely to portions above ground, the larva a little later cause whole plants to wither 

 and die. It is the practice of many farmers to sow an extra number of seeds in each 

 hill, so that, after some are destroyed, enough will still remain ; others protect their 

 plants with muslin or other screens, both from the attack of the imagos and from their 

 ovipositing on the plants; still otliciN sprinkli' their young plants with lime, paris 

 green, hellebore jiowder, or similar insecticides. Dr. II. Shinier discovered the larva 

 of a small ])arasitic fly occupying the abdomen of females of this beetle, and, liavinn- 

 bred the fly, named it Tdchina diahn>ticir. The fly larva leaves its hosts when it is 

 full-grown, and pupates on the surface of the ground, emerging from the pupa in less 

 than two weeks. Parasitism of the imagos of Coleoptera by Dijitera, as in Diabrodca, 

 is not very common. 



Another species of Diabroticu, of a greenish yellow ground color, with twelve larsre, 

 black spots — some of which are at times confluent — upon the elytra, is I>. duodnrim- 

 punctatu. The elytra of this species are not striate ; the abdomen and bases of the 

 femora are yellow. This species sometimes attacks cucumber, melon, and squash vines, 

 and is said to damage the leaves of the dahlia, but I have found it most abundantly on 

 the flowers of the golden-rod {SoUdaijo). The larvff of D. longicornis., another 

 species, bores in the roots of corn. 



