BEETLES. 317 



pods, etc., several are doubtless enemies of the Galeruca, though we have, as yet, no 

 proof of the fact. Many birds were observed on the trees infested by the beetles, but 

 the English sparrow, which was the most numerous, did not feed on the insect in any 

 stage of growth." 



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

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

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

 tudinal stripes on the elytra, three black spots on the prothorax, and one on the 

 head. 



Probably few persons have failed to notice the small, yellow and black striped 

 beetles, Diabrotica vittata, which swarm upon cucumber, squash, melon, and similar 

 vines, almost as soon as they appear above the ground. This beetle is 

 elongate-oval, about 0.22 inch long ; the elytra are striate ; the general 

 color is straw yellow with a black stripe along the middle of each 

 elytron, reaching from its base neai-ly to its tip and a stripe covering 

 the elytral suture ; head, knees, tips of tibiae, and tarsi are black. The 

 damage, often considerable, which this beetle does to young cucumber 

 vines above ground is slight compared with that which its larva does to the roots below 

 the surface of the soil. 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 the stems of 

 the plants. These eggs soon hatch, and the larva?, feed upon or bore into the roots 

 and stems of the plants for nearly a month, when they pupate in a little oval cavity 

 which they form in the ground. The pupal state lasts about two weeks. The larva? 

 are slender, cylindrical, about 0.4 inch long, and nearly white ; their head is brownish, 

 and they have a brownish spot on the dorsum of the posterior segment. This species 

 hibernates as imago, and is said to do so as pupa ; the rapid growth of its larva enables 

 it to have from two to three broods each year. In early spring, before cucumber vines 

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

 have found them especially abundant on the flowers of the shad-bush (Amelanchier 

 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 others sprinkle their young plants with lime, paris 

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

 of a small parasitic fly occupying the abdomen of females of this beetle, and, having 

 bred the fly, named it Tachina diabroticce. 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 Diptera, as in Diabrotica, 

 is not very common. 



Another species of Diabrotica^ of a greenish yellow ground color, with twelve large, 

 black spots some of which are at times confluent upon the elytra, is D. duodecim- 

 punctata. 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 (Solidago). The larvae of D. longicornis, another 

 species, bores in the roots of corn. 



