INSECT ENEMIKS OF TllK CODLING iMOTII. 245 



summer. After three or four days the mushu was removed, 

 the surviving moths were killed, and the ei^gs were then ex])osed. 

 Parasitization was determined by the colour of the codling eggs, 

 black indicating ])arasitization. It will be noted that no eggs 

 were parasitized until November y. Little parasitization occurred 

 until about the middle of December, after which there 

 was a rapid increase, until finally from January till about the 

 end of the fruit season an average of over 90 per cent, of the 

 codling eggs was destroyed by this natural enemy. This great 

 increase in parasitization was possibly partly due to the fact that 

 the laying of most of the codling eggs was concentrated on one 

 tree of the orchard. Those codling eggs resulting from moths 

 of January 9, 10, and February 4, were laid in other parts of 

 the orchard a considerable distance from the above-mentioned 

 tree. It will be noted in the table that the parasitization of 

 these eggs was a little less than 50 per cent. Observations of 

 this nature in 1916-1917, carried out in the same place, show, as 

 recorded in Table 4, that parasites did not appear until December 

 II, over a month later than in the previous year. 



Conclusions from the Study of T. litfca. — Resitlts 

 indicate that Trichogrammatoidca lutca has little influence on the 

 control of the first generation moths, but much is done to control 

 the later broods, since the parasite directly prevents the hatching 

 of about 50 per cent, of the codling eggs from mid-summer to 

 the end of the fruit season. Evidently much may l)e done to 

 control the later generations of moths by concentrated breeding 

 of the parasite. Its short life-cycle and many generations 

 during the summer season, its fairly large laying capacity, and 

 the tendency of one female to infest as many as 18 codling 

 eggs, make the potential powers of this parasite great in con- 

 trolling the codling moth. By the concentration ol codling 

 eggs for the parasite, more opportunity is given to it in order 

 to lay its maximum number of eggs in a maximum number of 

 eggs of the host. 



Other Parasites of the Codling ^Moth. 



Pimpla hcliophila Cam. — Next in importance to T. lutca as 

 a parasite of the codling moth is the. Ichneumon, Pimpla hcliophila 

 Cam., bred from codling larva and pup?e by Mr. C. P. Lounsbury 

 in 1906. This insect was named and described b}^ Cameron in 

 the " Transactions of the South African Philosophical Society," 

 vol. 16. pp. 337-339. The adult is illustrated in Plate XIX (70- 

 Seventy-three individuals were bred from 2,824 codling larvre 

 collected from Sauer's orchard at approximately lo-day intervals. 

 Doubtless in those orchards where collections of larv?e from 

 bands is not practised the parasite is more abundant, since 

 destruction of codling larvae by trapping also destroys the 

 immature individuals of this parasite. 



Gallic phialtes messor. — This parasite, which liad ])reviouslv 



