256 



STATE HORTICULTURAL SOCIETY. 



THE APPEARANCE OF THE INSECT. 



The immature insect. — Fig. 2. — These curious minute, oval, imma- 

 ture forms are called nymphs. When first hatched they are of a 

 translucent yellow color, and hardly visible to the unaided eye; eighty of 

 them placed end to end would scarcely measure an inch. They increase 

 in size quite rapidly and undergo gradual changes in color and 

 form until they measure .055 of an inch in length and .045 of an 

 inch diameter; the natural size is indicated by the hair line at the 

 right of the figure. These full grown nymphs are oval in 

 shape, and of a general blackish color often tinged with red; the 

 eyes are of a bright crimson color. A very conspicuous feature is the 

 large black wing pads on each side of the 

 body. The whole body is very much flat- 

 tened, being only one fifth as thick as long. 



The adult insect. — From the full-grown 

 nymph, the change is to the adult insect. 

 In this form the pest strikingly resembles 

 a cicada or dog-day harvest fly in minia- 

 ture. It would take nine or ten of them 

 placed end to end and about forty placed side 

 by side to measure an inch; the hair line be- 

 side the figure indicates the natural size of an 

 adult. From the wide blunt head, the body 

 tapers considerably to the sexual organs at the 

 caudal end. When the insect is at rest, its 

 two pairs of large, nearly transparent wings 

 slope roof-like over the sides of the body. 

 The general color is crimson with broad black bands across the abdomen' 

 The legs have thickened femurs to aid the insect in leaping. The sexes 

 are easily distinguished: in the male (Fig. 5) the abdomen terminates in a 

 large trough-shaped segment from which project upward three narrow 

 organs used in copulation; the end of the abdomen of a female (Fig. 6) 

 resembles a bird's beak, an upper and a lower pointed plate coming together 

 and enclosing the egg-sheath between them. 



Fig. 2 — Fall grown nymph, ventral) 

 view; a, anus; 6, beak. 



THE LIFE HISTORY OF THE INSECT. 



The life history and habits of every insect which becomes of economic 

 importance should be accurately determined in order to ascertain, if possi- 

 •ble, the stage when it can be most successfully combated. Observations 

 upon the habits of the two worst enemies to fruitgrowers, the plum curcu- 

 lio, Conotrachelns nenuphar and the codlin moth, Carpocapsa pomonellay 

 revealed peculiar habits which made it practicable to combat them with the 

 cheapest and most easily applied of the insecticides, — the arseuites. The 

 adult plum curculio's habit of feeding upon the fruit and foliage left it 

 open to attack by the arsenical spray. The eggs of the codlin moth were 

 found in the apex of the forming fruit soon after the blossoms had fallen; 

 the fruit then being in an upright position the arsenite lodges in the apex 

 and is eaten by the newly hatched larva when it attempts to enter the 

 fruit. A knowledge of the habits of injurious insects will also often ena- 

 ble the farmer to so manage his land and crops that the insects are placed 

 under very xmfavorable and often destructive conditions. Wheat sown as 



