12 



curving' toward the first, without change of position by the insect. The 

 ovipositor, however, is thrust in at a very considerable angle from that 

 assumed in the first case, so that it crosses beneath the bark the cut 

 first made, and the narrow intervening bark between the two incisions 

 is cut entirely loose. This has a very important bearing on the subse- 

 quent condition of the wounds made by the insect in oviposition. The 

 object is doubtless to cause a certain cessation of growth between the 

 two rows of eggs, to iirevent their being crushed and choked out by 

 the rapid growth of the twig, and it is due to tliis peculiarity that the 

 injury to the young limbs later assumes so serious a nature. A single 

 incision made by the insect to contain its eggs would heal over and 



cause little after-damage, but with the 

 combination of two incisions and the 

 killing of the intervening bark, causing 

 it to adhere to the wood, a large scar 

 is produced, which, with each subse- 

 quent year's growth, enlarges and 

 ultimately assumes an oval form, the 

 dead bark of the center breaking out. 

 After a few years, limbs which have 

 been thickly worked on by the insect 

 become very scabby and rough, are 

 easily broken off b}^ the wind, and are 

 very liable to attack by wood-boring 

 insects. (See Fig. 7, e.) After complet- 

 ing the two complementary slits and 

 filling them with e^^g^^, the female rests 

 a considerable time before again begin- 

 ning operations. The number of eggs 

 deposited by a single female exceeds 

 100, and possibly 200. Rather late in 

 the fall a female which had just 

 finished a pair of slits which contained 

 some 2i) eggs was found to still contain 

 40 eggs in her ovaries. The adults first appear about the middle 

 of July, and become most numerous during August and September. 

 They begin oviposition about the middle of August, or even earlier, 

 and continue this work until they are killed by the frosts of early 

 winter. In Kansas I have found them busily ovipositing as late as the 

 24th of October. The eggs remain unchanged or dormant in the twigs 

 until the following spring, hatching in May or early in June. 



The eggs of the bufi'alo tree-hopper are subject to the attacks of at 

 least two minute egg-parasites. • One, an undescribed species of Cosmo- 

 coma, Miss Murtfeldt reports had destroyed the larger proportion of 

 eggs sent her from various localities in Missouri. Mr. Jack probably 

 refers to the same x^arasi tic insect which he says he observed, Septem- 



FlG. 7. — Ceresa bvbalu.i Fab. : Twig of 

 apple showing: a, female at work; 6, recent 

 egg-puDctures; c, bark reversed with eggs 

 in position, slightly enlarged; d, single row 

 of eggs still more enlarged; e, wounds of 

 two or three years' standing on older limbs 

 (adapted from Marlatt.) 



