NUT-FEEDING HABITS OF THE CODLING MOTH. 69 



lett pear crop around Concord, Cal., is picked prior to this time and 

 before all the second-brood moths have developed. It is entirely 

 probable that these late-appearing individuals seek the walnut as the 

 only remaining plant suitable for oviposition. Thorough search 

 during May and June, 1910, failed to show the presence of any larvae 

 on trees that were badly infested last season. 



Life of larvae in walnuts. — In spite of the extreme bitterness of the 

 fleshy hull, some larvae thrive well there for a time before entering 

 the kernel, as several specimens of healthy, active larvae one-fourth 

 to one-half grown were found in the hull. However, in all cases 

 under observation the larvae left the hull and entered the kernel be- 

 fore reaching maturity. The majority of the larvae burrow directly 

 through the fibrous tissue connecting the halves of the shell. Some 

 larvae are saved the necessity of burrowing through the hull, as this, 

 during the period of infestation, is ripening on many of the early 

 nuts, and on account of the parting of the lobes the small larva has 

 only to eat its way through the thin fibrous connection. No case was 

 noted where the larva entered through the shell. 



Time required for development. — No individual records were kept, 

 but all observations show that the larva develops as rapidly on the 

 meat of the walnut as it does in apples at this season of the year. 

 Some larvae less than a week old, collected in walnuts October 5, 

 reached their full development and were spinning cocoons by the 

 middle of November. Others, however, continued to do more or less 

 feeding on the kernel and did not spin cocoons until January. 



Hibernation. — From 1 gallon of infested walnuts kept at the 

 laboratory perhaps one-fourth of the larvae cocooned and pupated 

 inside the shell. Others, leaving the walnuts at the same place where 

 they entered — that is, through the fibrous tissue connecting the halves 

 of the shell — pupated in bits of paper and rags kept in the jars. 

 Before pupating in the walnuts, the larva prepares an opening 

 through the fibrous tissue sufficient for the exit of the moth and spins 

 its cocoon immediately adjoining this opening. Upon the emergence 

 of the moth the shed pupal skin is left outside on the end of the 

 walnut, as is shown in Plate VIII, figure 1. All larvae under observa- 

 tion pupated between February 20 and April 10. 



Adults. — Moths emerged in numbers from the above material dur- 

 ing April and May, 1910, comparing closely with the emergence 

 record of moths from a quantity of overwintering larvae taken from 

 bands on apple trees the previous season. 



Identification. — Numerous adults emerging from this material 

 were submitted to Mr. August Busck, of the Bureau of Entomology, 

 for identification. Mr. Busck has definitely determined these as 

 Carpocapsa pomonella L. ; he states that the European Carpocapsa 

 putaminana Staudinger, recorded as feeding on walnuts in Europe, 

 is now regarded as a variety of pomonella. 



