358 



INJURIOUS AND BENEFICIAL INSECTS OP CALIFORNIA. 



to bloom. They deposil their eggs singly in the sepals of the flowers 

 or in the upper portion of the calyx cup, always on the blossom buds, 

 just before the petals open. The insertions are made by the sharp 

 ovipositor and the eggs are well buried in the plant tissues. In the 

 interior valleys egg-laying begins about the middle of March. Usually 

 but one egg is deposited in a single flower, though this is by no means 

 a fixed rule. 



The eggs hatch in about four or five days, though the time may vary 

 from three to six days. Soon after hatching, the young larva?, eat their 



way into the young cherries and 

 work upon the tender kernels, 

 where they feed from two to 

 four days, or until the interior 

 is devoured and the fruit with- 

 ers. They then seek new cherries 

 and repeat the process, each 

 destroying a second and often 

 a third lief ore becoming full- 

 grown. By the time the third 

 cherry is reached the kernel is 

 too hard to be eaten, so only 

 portions of the meat around it 

 are consumed, which often in- 

 cludes nearly or over half of 

 the fruit. The entrance to the 

 first cherry is exceedingly 

 obscure, but the small, round 

 holes are plainly visible in the 

 second and work on the third 

 is very conspicuous. 



It is not known if the above 

 data hold true with regard to the insect's work on the prune, plum 

 and other hosts, for the complete life history has not been studied in 

 the localities where these fruits are attacked. The larva? reach maturity 

 in from twenty-two to twenty -six days and then leave the fruit to enter 

 the ground, to a depth of from three to seven inches, for pupation. The 

 pupae remain in the ground over winter and emerge as adults in March, 

 when egg-laying begins, as soon as the well-formed blossom buds appear. 

 There is but a single generation a year. 



Nature of Work. — Evidences of the work do not show until the 

 young cherries begin to turn yellow and drop. Examination discloses 

 the small, round holes and the empty interiors. Later fruits show much 

 of the fleshy portions around the seeds removed. In not a few cases, 

 from 50 per cent to nearly 90 per cent of the fruit is injured and drops 

 prematurely because of the attacks. Other fruits are also injured in a 

 similar manner. 



Distribution. — The insect is generally distributed throughout the 

 San Franeisco Bay region, the Sacramento Valley and the Sierra foot- 

 hills, east of the Sacramento Valley. It also extends into Oregon, 

 where considerable damage is done, in the Rogue River Valley. 



Fig. 354. — Cherries showing the work and 

 larva of the cherry fruit sawfly, Hoplocampa 

 cookei (Clarke). Natural size. (Author's 

 illustration, Mo. Bui. Cal. Hort. Com.) • 



