1922 ENTOMOLOGICAL SOCIETY. 17 



The abundance of feeding is very variable, and we did not obtain very definite 

 data upon the probable catches made by our experimental traps. At night there were 

 frequently as many as 20 to 30 moths, of which over 50% were female, feeding on 

 a single trap at a time when very few were attracted to troughs of molasses. By day 

 males were found feeding at all hours, though they were most abundant between 

 the hours of two and five p.m. Females appeared less frequently in the morning 

 and were seldom seen in numbers till about 4 p.m., by which time they visited the 

 traps freely and were nearly as numerous as the males on golden-rod blossoms. 



'We did not discover that quassia would retain the majority of moths that 

 visited a trap till too late in the season for this to supply us with many data. 



In the laboratory, however, and with a few. bottle traps, we found that the 

 deterrent effect of quassia is very slight and that it is readily overcome by the 

 addition of a little saccharine to the bait. 



The effect of quassia on moths is very variable, and it cannot be predicted for 

 the individual. Moths captured feeding on flowers, were offered a choice of 

 formulse. Those containing quassia and saccharine were preferred to straight 

 molasses. This wag also demonstrated in the field. At a strength of two ounces to 

 a quart of solution quassia ikills about 65% of all moths that feed on it. In some 

 cases death is rapid, and within ten minutes of feeding either sex of P. orthogonia 

 loses all power of locomotion, lies on its back and response to stimulation becomes 

 continually less apparent till it ceases entirely. Death in such cases appears to be 

 gradual and progressive. In other cases moths feed freely on the bait for a few 

 minutes and suddenly flop around the receptacle as though in great pain, till sudden 

 death puts an end to their activity. 



On the other hand some 35% of the moths which have imbibed quassia solution, 

 sometimes more extensively than have those which die, become either very sluggish 

 or quite inactive a few minutes after feeding and they may remain in this condition 

 for two or three days. iSometimes females, which have been quite inactive for 

 over 24 hours, will laboriously struggle to their feet, lay a few eggs, and relapse 

 into inactivity. Recovery in other cases appears to be complete, and since it per- 

 mits oviposition, we have retained the use of fly pads in addition to quassia. Our 

 experiments indicate that very few moths will recover from the effects of the latter 

 before they succumb to the arsenical poison of the former. 



At present our poisoned (bait formula, therefore, consists of : — a 10% solution 

 of cane molasses, the diluent being water in which quassia chips have been soaked 

 overnight at the rate of two ounces to the quart. In each bottle of this solution 

 is inserted one fly pad, sufficient saccharine to cover a Canadian 5 cent piece (1 

 gram) , and eight drops of amyl acetate. 



This formula undoubtedly can be improved considerably both as regards its 

 attractiveness and poisoning quality. As it stands, all of the materials, with the 

 exception of amyl acetate, which is not essential, can be obtained in any village. 



The present retail cost of materials for a dozen traps, including the bottles, 

 is approximately $2.65. 



We have no definite data as to what distribution of traps will give the greatest 

 returns for money expended, but believe that one to every ten rods of fencing 

 around a field that is free from flowering weeds should be sufficient to reduce an 

 outbreak very materially. On weedy fields subsidiary posts erected in the field 

 might be necessary. 



