214 E. A. HARTLEY Vol. XXII, No. 8 



Seasonal. 



The data on this point are Ukewise very scant. Practically 

 all records show that Aphelinus appears rather late in the sum- 

 mer and fall. The writer did not find it about Columbus until 

 the first of November, in spite of the fact that he was collecting 

 aphid parasites there from the middle of September on. Mr. 

 T. H. Parks*, who was with Webster and Phillips in Kansas 

 during the work with the "green bug" parasites, is of the open- 

 ion that Aphelinus does not become numerous until late fall. 



Winter is probably passed in the pupal stage within the 

 blackened remains of the host, according to the observations of 

 Kurdjumov ('13) working with a similar species in Russia. A 

 few attempts were made to carry it through the winter in 

 hybernation cages outdoors in Columbus, but all failed, even 

 though Aphidius confined with them emerged on the first warm 

 days of spring. These attempts were repeated the following fall 

 and winter in Philadelphia with no better success. 



As soon as the weather began to moderate in the spring an 

 outdoor wire-screen cage was established over some dock plants 

 {Rnmex obtusifolius) in which was placed a colony of parasite- 

 free Myziis persicce, together with ten or fifteen Aphelinus 

 semiflavus, to note the behavior of the parasite out of doors at 

 this season. Observations began on April 11th and continued 

 every other day until May 13th, and then every few days until 

 May 24th, when the experiment was closed. 



On the first night after the cage was established there 

 occurred a slight frost which numbed the parasites for a time, 

 but they became active again as soon as the sun came out. 

 Several warm days followed, with rather cool nights, and then 

 about a week of cool rains followed by more warm days. 



Several parasites were observed in the cage among the 

 aphids for three or four days, when they disappeared. On the 

 25th of April, one live Aphelinus was again observed in the cage 

 ovipositing in the aphids. Observations were made on this one 

 intermittently until May 20th. The aphids multiplied rather 

 slowly for the first ten days in the cage and then gradually 

 recovered their normal rate, producing a good supply of young. 



* Private communication. 



