LIFE HISTORY OF THE SQUASH- VINE BORER. 39 



the stems as late as the middle of October in Columbus, Ohio, and 

 still later iu the District of Columbia, would suggest this and careful 

 observations show that the species is partially double-brooded in this 

 latitude, practically single-brooded on Long Island and northward, and 

 fully and normally two-brooded in the Gulf States. Imagos were reared 

 many years ago by John Abbott in Georgia, August 11, from larvas 

 which spun up July 1G ; by Kellicott at Columbus, August 20 and after- 

 ward ; and indications are that a moiety, probably less than half, nor- 

 mally develop the first year in the latitude of Columbus, while the 

 remainder winter over as larvae and complete transformation the follow- 

 ing year. In New Jersey, according to Dr. J. B. Smith, the species in 

 exceptional cases completes its transformations "late in August or in 

 September." 



From larvae obtained in 1898 and kept feeding in our rearing jars at 

 this office a moth was obtained August 25. A pupa from which the 

 moth had already issued was also found the same day under a cover 

 placed over a borer-infested squash plant on the grounds of the Depart- 

 ment. Larvae, which undoubtedly belong to the second brood, are 

 always to be found in the vines in the District during October, and some 

 are still to be seen in November as late as the second week, as hap- 

 pened the past year. The plants, cymlings and pumpkins, upon which 

 these larvae were observed were all planted in July, one lot in which a 

 larva not quite full grown was found October 1G, having been planted 

 July 16. Moths of the first generation were observed that day and as 

 late as July 22. 



TIME OF APPEARANCE OF THE MOTH; NUMBER OF GENERATIONS. 



For lack of opportunity of frequent observation the earliest appear- 

 ance of the moths in the District of Columbia and vicinity has not yet 

 been ascertained. At the times when moths have been sought for in 

 June and early July they have hitherto escaped observation. Yet the 

 larvae have been found full grown (25 mm long) in squash stems on our 

 experimental plat as early as July 16. This happened in 1897, a year in 

 which the season was estimated to be at least two weeks late; and from 

 this it appears probable that the larvae mature here in normal seasons 

 as early perhaps as the first week of July. The seed in this case was 

 planted June 5. Larvae are to be found in the latitude of the District 

 of Columbia from some time in June until as late as the second week 

 in November, provided that food be obtainable for them, and this even 

 though several frosts may have occurred and the plants be dead. 



It is evident from the facts observed that there are three lots of moths 

 occurring during the year, each lot following or even being "over- 

 lapped" by the preceding one. The first lot appears late in May or 

 early in June and July, and probably is the offspring of the larvae of 

 the first brood, which have wintered over instead of issuing as images 

 the first year. The second lot appears later in July and early in 



