34 HOMOPTERA 



them. In this method little datnage is done to the host, as the injury is not a severe one and quickly 

 heals. In another type of oviposition, the insect makes a curved sHt in the bark and another close 

 beside it in a series of spiral incisions around the stem. This affects the plant more seriously as in 

 some cases the wounds fail to close which not only interferes with growth but affords entrance for other 

 insects and for fungi, and in other cases small stems may be so punctured that they break ofif at the point 

 of injury. A nuinber of species deposit in the buds of the host. In this type of oviposition theeggsare 

 laid just beneath the outer bud scales, and the nymphs emerge at the time when these scales are first 

 opening. In a few cases the eg^s are not entirely covered but project slightly out of the bud tissue. 

 This method of oviposition has but little injurious effect on the host, since the outer bud scale. being 

 entirely protective, may be damaged without injuring the plant. In the case of fruit buds the injury 

 may be more serious, but in no case has it appeared to an extent great enough to be considered import- 

 ant. A few species lay their eggs in the leaves. Usually the under side of the leaf is chosen for 

 oviposition and the eggs are generally placed in two rows, one on each side of the midrib. The egg 

 is seldom entirely within the leaf but the tip is plainly visible. A number of species choose the axil 

 of the leaf for oviposition and a few are known to oviposit in the roots or in the base of the stem just 

 below the surface of the grounii. 



The mechanics of oviposiiion differ decidedly in various species. In most cases the ovipositor 

 is extended at right angles to the body and thrust perpendicularly into the host where it remains until 

 all the eggs making the compleinent of a single egg mass are deposited. The ovipositor seems to move 

 but slightly in the egg slit during the process, although a considerable movement of the abdomen is 

 observable. In other cases the entire egg slit is made first and then the ovipositor is inserted perpen- 

 dicularly and gradually moved backward during the process until it is almost parallel with theabdomen. 

 In still other cases the insect makes the egg sHt and inserts the egg at the same time. The ovipositor 

 moves slowly through the bark, forcing the tissues apart and depositing the eggs in one movement. 

 With a few species tiie ovipositor is withdrawn from the host after each egg has been deposited, and 

 reinserted for the next egg. In one species which was carefully studied, the insect lays a number of 

 eggs, then rests, then moves foiward along the same sHt and deposits more — generally a different 

 number — then rests again, and so on until a complete row has been finished. The writer's obser- 

 vations have been tliat ovipnsition occurs most often when the sun is warmest and the temperature 

 highest and usually on that side of the tree or plant which is exposed to the most direct rays of the sun 

 when the process is in progress, but VVildermuth (191 5) has reported a species which oviposited chiefly 

 at night or early morning, so that apparently there is considerabie variation in this matter. 



The number of consecutive ovipositions made by one female varies with the species but has not 

 been greater than five in any species noted. The average is not over three. In most cases the insect 

 after depositing one egg mass moves along the twig for a short distance and repeats the process after a 

 very short interval of rest. Oiie female generally lays all her eggs on one twig or on twigs very close 

 together, and it has never been observed that the insects move from one plant to another during the 

 process. While ovipositing, the insect is entirely occupied with her work and does not respond to 

 external influences. She refuses to be disturbed and may be touched or pushed without interrupting 

 the process. Tlie writer has often attempted to take a female from a branch while oviposition was in 

 progress, and in doing so has broken off the ovipositor, which remained in the egg slit. The time 

 required for a single oviposition varies from ten minutes to half an hour. Where several egg masses 

 are deposited in succession, the resting period between each insertion increases; so that if fifteen 

 minutes elapse between the first and second, a half hour may elapse between the second and third, and 

 often seveial hours before a fourth if so many are made. The same female may, however, continue to 

 lay eggs for several days until a large number have been deposited. Daily field records indicate that 



