186 



The Apple Sawfly. 



cates with the exterior by a small round hole, which is 

 usually noticed near the eye of the apple or on the side. 

 Out of the external opening one frequently finds " frass " 

 and moisture exuding. Attacked fruitlets can thus be 

 easily seen on a tree long before they fall. These larvae 

 may be found of all sizes in June and July ; there are 

 apparently two broods which more or less overlap. The 

 average length of larval life seems to be varied, some mature 

 in four weeks, others take nearly five weeks to attain their 

 full-fed condition. If the fruitlet decays before the larva is full 

 fed the larva leaves it and crawls to another. When the 

 attack has been early and the fruit very small, one larva has 

 been traced to attack and destroy no less than five young 

 apples. They seldom seem to fall with the fruit ; either they 

 erawl from one fruit to another, if not mature ; or when the 

 fruit they have been feeding on is decayed, they fall from 

 it when mature and pupate in the soil. 



The pupae are buried an inch or so under the earth, up to 

 a depth of four inches according to Miss Ormerod. Frequently 

 the larvae only just bury themselves. The pupa is encased in 

 a small dull yellow cocoon of silk and saliva, which is coated 

 outside with grains of earth. Larvae which fell from the 

 apples at the end of May had pupated by the 13th of June. 

 These hatched out into perfect flies on July 7th, forming a 

 second generation. This second generation also lays its eggs 

 in the apple, large fruit being sometimes attacked in 

 July and August. Larvae have been found as late as 

 September 3rd, but one seldom finds many after the end of 

 July. This second brood remains in the larval state all the 

 winter in the cocoons of silk and earth under the trees. 

 Mature larvae have been found on May 10th, and at the same 

 time many were found quite small, so that there may be more 

 than two broods. In any case a second generation arises 

 from the spring brood, when the larvae mature as early as 

 first mentioned. 



It is said by some observers that the larvae do not fall out 

 of the fruit when mature, but fall with the fruit. This 

 certainly is not the rule. One tree examined during the 

 present season had thirty fruitlets that had been attacked 



