48 



BULLETIN 189, U. S. DEPARTMENT OF AGRICULTURE. 



skin at some other point. After freeing themselves from the host, I 

 all that were observed writhed about actively for a few minutes 

 and then died. Many of the hairworms did not escape from the : 

 codling-moth cocoons, but were found, at the time of the regular 

 examinations of the jars, knotted together and dead, beside the 

 flattened and shriveled larval remains. Table XLII shows the 

 extent of parasitization at French Creek in 1911. 



Table XLII. — Extent of 'parasitization of codling-moth larvae by hairworms at French 



Creek, W. Va., in 1911. 



Date larvae were collected. 



June 26.... 



Julv3 



Julvl4.... 

 July 24.... 



Aug. 4 



Aug. 15 



Aug. 23. . . . 



Sept. 2 



Sept. 13... 

 Sept. 19... 

 Oct. 3 



Total 



Number 

 of larva? 

 collected. 



L39 



68 

 48 

 24 

 11 

 51 

 34 

 36 

 43 

 23 

 22 



Number 



of larvse 



parasitized 



Per cent 

 parasitized. 



12.50 

 4.17 

 21.43 

 13.72 

 32.35 

 63.90 

 48.84 

 43.48 

 27.27 



17.53 



SUMMARY. 



The foregoing account of the codling moth is based upon band- 

 record studies conducted in 1911, 1912, and 1913 in several different 

 localities of Virginia, West Virginia, and Maryland. 



The stations at which the investigations were conducted comprise 

 a difference in latitude of about 1° 40' and in altitude of about 

 3,100 feet. The most southerly and least elevated station was at] 

 Charlottesville, Va., the most northerly at Hagerstown, Md., and 

 the one at highest elevation at Pickens, W. Va. 



The chief features of the investigations consisted of banding 

 suitable apple trees with strips of burlap, collecting at regular periods 

 the larvse that went beneath the bands to spin up, and rearing these 

 larvae in jars kept in the localities where the larvae were collected. 

 Examinations of the bands and rearing jars were made every week 

 or ten days in 1911 and twice a week in 1912 and 1913. No detailed 

 life-history studies were attempted. 



During a single year the codling moth, in the region covered by 

 the present studies, produces one full brood of larvae and a partial 

 second brood, the size of the second brood depending more or less 

 on the latitude and altitude of the locality. 



The studies show a marked difference in the time of appearance of I 

 the different broods in different localities. Charlottesville gave the 

 earliest records for practically all broods and Pickens the latest. 



