564 NEW JERSEY AGRICULTURAL COLLEGE 



the usual time, and, also, that sections of bogs not entirely covered by 

 water were first and most seriously infested, later broods starting from 

 these centers. 



The explanation was simple enough with all the facts at hand. The 

 moths remained dormant a week or ten days later than usual, and 

 when they were ready to oviposit the bogs were wholly or partly bare. 

 The highest vines were cleanest and most nearly ready to start, hence 

 were selected by preference. Drawing, therefore, should not be wholly 

 by date, even if the yellow-head only is aimed at ; but it should be at 

 a date when nature has reached a normal May 1st period. Oviposition 

 usually begins before the middle of April, and by the 1st of May well- 

 advanced larvae may be found, the hibernating adults themselves hav- 

 ing disappeared. 



Water temperatures do not enter into this Teras problem at all, but 

 the matter is different with the black-heads, where the eggs hibernate 

 on the leaves. We know that these eggs hatch on exposed vines before 

 the water is normally taken off, and larvae may make their appear- 

 ance on flooded bogs a few days after the water is drawn. The problem 

 here is to discover the hatching temperature and how long the egg 

 must be submitted to it before the larva develops \inder water — if it 

 develops at all. 



To ascertain these points a series of observations was planned, in- 

 cluding temperature records on the water covering the bogs. Mr. 

 I. W. Budd, of Pemberton; Mr. A. J. Rider, of Hammonton, and 

 Miss Elizabeth C. White, of New Lisbon, agreed to co-operate, and 

 under my immediate direction Mr. E. L. Dickerson, my assistant as 

 State Entomologist, was to make observations at Jamesburg. And 

 then began the chapter of accidents ! It was found, when the ther- 

 mometers were ordered, that none adapted for taking water tem- 

 peratures at varying depths were carried in stock, and they had to Ix? 

 especially made. When completed, some failed to work on receipt 

 and others were broken in transit, so that it was not until April 19th 

 that any records were made. Fortunately this proved to be early 

 enough, because the air temperatures could be supplemented by the 

 records of the State Weather Service, and the relation of water to 

 air temperature appears fairly from the records made. 



