97 



injured the vines to a slight extent, but no moths could be seen feeding 

 on it, nor could dead ones be discovered in the vicinity. 



From these tests it is safe to conclude that the use of poisoned sweets 

 can never be a success in trapping the moths. 



LENGTH OF LIFE CYCLE. 



The duration of the embr3^onic, larval, and pupal instars has already 

 been discussed, and the length of the life cycle is easily had by com- 

 bining these records made on the same individuals. 



This has been done in the following table, which gives the duration 

 of a series of life cycles during the different parts of the season of 

 1904, at Paris, Tex. 



Table XXXVIII.— Len^/^/i of life cycle at Paris, Tex., 1904. 



Eggs laid. 



Eggs hatched. 



Larvae pupated. 



Moth emerged. 



Life 

 cycle. 



Sum of 

 effective 

 tempera- 

 tures. 



April 2 



April 10 



Mays 



May 31 



Days. 

 59 

 52 

 53 

 41 

 32 

 30 

 36 

 48 

 35 

 63 



°F. 

 1,485 

 1,420 

 1,601 

 1,597 

 1,237 

 1,186 



April 12 



\pril 19 



May 16 



June 3 



April 29 :... 



Mays 



June 3 



June 20 



July 6 



July 9 



Jnlv97 



August 16 



July 16 



July 19 Auffust 2 





Augusts 



Do 



Augusts 



do 



August 22 



September 4 







1,573 



August 28 . 



Augusts: 



September 8 



September 16 . . . 



September 27 



October 15 



1,319 



September 5 



September 24 



October 10... 



1,138 



September 18 



October 10 



November 15 















1,417 















At Victoria, the previous season, some life-cycle records were made 

 early in the year, averaging as follows: 



Table XXXTS..— Length of life cycle at Victoria, Tex., 1903. 



Eggs laid. 



Eggs hatched. 



Larvae pupated. 



Moth emerged. 



Life 

 cycle. 



April 14 



April 18 



May 16 



June 2 



Days. 

 49 



May 3 



Mav6 



May 28 



June 14 



42 













The influence of the seasonal variation in temperature is ver}^ plainly 

 to be seen, the length of the life cycle decreasing from fifty-nine days 

 earl}^ in the spring to only thirty daj^s during the hottest part of the 

 summer. 



It will be noted that the sums of effective temperatures for the dif- 

 ferent records vary from 1,186^ to 1,601°, with an average of 1,417° F. 

 This latter may, no doubt, be accepted as very near the normal at 

 moderate summer temperatures. 



