76 



two dates, Mr. Ratliff's notes give the following record of minimum temperatures 



through which the insect must have necessarily passed. 



September 23 (frost) .'.. 26° 



October 6 (light frost) 26° 



October 11 (light frost) 34° 



October 12 (light frost) 26° 



October 14 (heavy frost) 24° 



October 15 (frost) 26° 



October 16 (light frost) 29° 



Rains on September 11, 26, October 10. Total precipitation during September and 

 October, 2.50 inches. 



At La Fayette, the same year, I found adults ovipositing on November 3, but of the 

 origin of these flies of course nothing was known. The temperature through which 

 these must have passed, supposing the eggs from which they evolved were deposited 



after September 1, was as follows : 



Min. temp. 



September 23 „ 39° 



September 24 (first frost) 29° 



October 11 39° 



October 12 (frost) 29° 



October 14 (frost) ...33° 



October 15 (frost) 31° 



October 16 33° 



October 19 (frost) 31° 



October 20 (light snow) 37° 



October 21 29° 



October 22 21° 



October 25 (frost) 19° 



October 26 (frost) 21° 



October 27 (frost) 2lo 



October 28 (frost) .„. 28° 



October 29 - 33° 



October 30 (frost) 19° 



October 31 23° 



November 1 (frost) 28° 



November 2 (frost) .._ 36° 



November 3 (frost) 32° 



Rains on September 7, 13, 14, 22, 27, 28, 29, 30, October 3, 9, 10, 12, 

 23. Total rainfall, 4.64 inches. 



From this it will be observed that the adult flies may emerge and 

 oviposit under what we suppose to be very adverse circumstances. To 

 what extent the eggs and young larvae are able to withstand such 

 weather I have no facilities at present for demonstrating. The major 

 portion of the small brood of flies, however, emerge during a more 

 favorable period, and for meteorological aid against these we can only 

 look to the dry, hot weather of July and August, though to the south 

 a portion of September might be included. But the straggling indi- 

 viduals, which, as I have proved, may originate from stubble, volunteer, 

 or even early sown grain, and which I myself can find no satisfactory 

 reason for not considering either the retarded or accelerated individuals 

 of either one or the other or both broods, have it in their power to repro- 

 duce a considerable progeny, which, though of themselves not a serious 



