REPORT OF CRANBERRY SUBSTATION FOR 1916. 229 



to be entirelj^ absent on some flowed bogs on which it infested from 76 to 

 89 per cent, of the eggs in 1915. Its great reduction on the flowed bogs 

 ma}' have been due to the long period of wet weather in the first half of 

 the groAnng season. 



The Braconid (Phanerotovia franklini ^ Gahan) parasitism was found to 

 range from 24 to about 55 per cent, on dry bogs (without winter -flowage) 

 and from none to about 33 per cent, on flowed ones. On one bog which 

 had the -ninter-flowage held until May 25, 24 per cent, of the fruit worms 

 were infested mth this parasite, and on another, bared of the winter water 

 on May 14, 21 per cent, were infested, these figures indicating that moder- 

 ately late holding of the flowage perhaps does not reduce this parasite in 

 proportion to its host as seriously as was suggested by the writer in last 

 year's report (page 40.) It should be stated in this connection that the 

 percentages of Phanerotovia and Pristomeridia parasitism given in this 

 and previous reports only show the amounts of these parasitisms among 

 the worms at work in the berries when the examinations were made, and 

 indicate the parasitism of the entire season only in a very rough way. It 

 was discovered this year that the parasitized worms leave the berries 

 somewhat sooner than the unparasitized ones, examinations made toward 

 the end of the pest's period of activity showing greatly reduced percentages 

 for the worm parasitism as compared with those made earher. Worms 

 from the same location on one bog showed percentages of Phanerotoma 

 parasitism on different dates, as follows: September 3, 33.3 per cent.; 

 September 6, 40 per cent.; September 13, 2.3 per cent. The percentages 

 of Pristomeridia parasitism found in this same location were as follows: 

 September 3, 5.5 per cent.; September 6, 6.6 per cent.; September 13, 0. 



Pristomeridia agilis ^ was very scarce this year, the percentage of, its 

 parasitism being found to range from none to 5| on flowed bogs and from 

 4^ to about 10 on strictly dry ones. 



The examinations by which the percentages of Phanerotoma and Pristo- 

 meridia parasitism given in this and previous reports were determined 

 were made by crushing fruit worms between glass slides in such a way as 

 to expel their viscera through the anal opening, the parasite larva, when 

 present, apparently always being ejected with them and being found 

 easily with a good hand lens. 



A number of eggs deposited at the same time by Phanerotoma females 

 under observation in eggs laid by fruit-worm moths in confinement where 

 they were secluded from parasites, and subsequentlj'' kept in closed bottles, 

 were examined with a microscope successively at various times after depo- 

 sition. None of these parasite eggs examined after either thirty-six or 

 forty-two hours showed any sign of hatching. Two of three examined at 

 the end of forty-six hours had hatched, but the larvse showed no sign of 

 life. After forty-nine hours all the eggs had hatched, and some of the 



1 This parasite, called Phanerotoma tibialis in the writer's previous reports, has recently been 

 described as new to science, and given the name here used, by Mr. A. B. Gahan of the Bureau of 

 Entomology. Cf. Proc. U. S. Nat. Mus., Vol. 53, 1917, p. 200. 



* The exact identity of the species is still in doubt. 



