THE CALIFORNIA PEACH BORER. 



69 



insectary, and to note the development of the eggs. (See. PL IX.) 

 Oviposition under these conditions was more or less unnatural, but the 

 eggs thus placed developed under perfectly normal conditions. The 

 period from oviposition to the time of hatching, as indicated in 

 Table I, lasted from 11 to 19 days, with an average of 14 days. There 

 were several hundred eggs in each lot. 



Table I. — Length of egg stage of the California peach borer (Sanninoidea ovalescens). 



Lot No. 



Date eggs placed. 



Date eggs hatched. 



Number of 

 days. 



1 



2 



3 



4 



5 



July 8-9 



July 27-28 



July 31 



Aug.3 



Aug. 1-4 



Aug. 3-6 



19 



13 



14 



11 to 14 



13 to 15 



14 to 15 



July 18 



July 20 



July 21-22 



do 



6 



July 23-24 



Aug. 7 



In escaping, the larva breaks a circular hole through the micropyie 

 or depressed end of the egg and leaves the eggshell attached to the 

 tree. The eggshell remains thus attached throughout the summer 

 and fall until early winter rains dissolve the glue by which they are 

 attached. 



FERTILITY. 



Many eggs gathered from different rearing cages in our numerous 

 experiments were noted "to determine what proportion was fertile, 

 with the results shown in Table II. 



Table II. — Proportion of fertile eggs of the California peach borer. 



Lot No. 



Fertile 



eggs 

 hatched. 



Sterile 

 eggs not 

 hatched. 



Total. 



Lot No. 



Fertile 



eggs 

 hatched. 



Sterile 

 eggs not 

 hatched. 



Total. 



1 



43 



42 



75 



139 



71 



204 



198 



3 

 42 



3 

 15 



3 

 44 







46 



85 



78 



154 



74 



248 



198 



8 



196 



55 



202 



3 

 

 3 



199 



2 



3 



4 



9 



10 



Total 



Percentage 



55 

 205 



5 



1,225 

 91.28 



116 



8.72 



1,342 



6 



100 



7 











THE LARVA. 



FEEDING HABITS OF NEWLY HATCHED LARVAE. 



The newly hatched larvae (fig. 22, a) are extremely active and 

 move about freely and they may crawl for a considerable distance 

 from the egg. After hatching they immediately seek out protected 

 places, either by hiding in cracks of the bark or under particles of 

 dirt or loose bark, or they go below the surface of the ground and 

 then at once begin to enter the tree. 



Newly hatched larvas were closely observed many times as they 

 entered the bark. We were never able to watch newly hatched 

 71419°— Bull. 97—12 6 



