﻿6 BULLETIN 1364, U. B. DEPABTMENT OF AGRICULTURE 



where they were released June 11, 87 hours after having been closed. 

 Nine pints of dead bees were removed from the eight hives, whereas 

 only 3.75 pints had been taken from them at Winthrop upon their 

 arrival from Philadelphia. It is safe to say that 6 of the 9 pints 

 died on account of the poison, not taking into account the cooler 

 weather and less crowded condition in favor of the bees in the hives 

 during their journey to Washington. 



In regard to the dead bees caught in the bee traps, it was found 

 in the preliminary experiments that the average daily number per 

 trap, counted before the trees had been sprayed, was 18, which rep- 

 resents about 3 per cent of all those that died, the 97 per cent dying 

 in the field. The average daily number of dead bees per trap, 

 counted in the traps at Winthrof) after the trees had been sprayed, 

 was 136. Evidently the bees in the sprayed orchard died more than 

 seven times as rapidly as those in a normal environment. This ratio 

 does not include the hundreds of sick bees that crawled out of the 

 traps and died in the grass near the hives. If it had been possible to 

 count all the bees that died from the effects of the poison and all 

 those that died normally, the proportion of deaths from poisoning 

 would certainly have been many times higher. 



The unusual mortality of the bees was first noticeable the second 

 day after they had had access to the sprayed flowers ; on the third day 

 after they had been poisoned the damage was unmistakable. This 

 heavy mortality continued as long as the sprayed flowers lasted, and 

 in some of the colonies did not cease until all the bees had died. 

 Most of the sick and dead bees appeared to be young, and many of 

 them bore wax scales. The field bees seemed to have died in the fields 

 as usual, although onlj a few of them were found dead daily on the 

 sheets under the sprayed trees. Under normal conditions the few 

 field bees that die in the hives represent only a small percentage of 

 the total number of the dead. Most of the dead and sick bees had 

 swollen abdomens and often when an abdomen was gently squeezed 

 a thick yellowish liquid was discharged from the anus. Most of the 

 sick bees clustered for a short time in the traps, and later many of 

 them climbed to the tops of the traps, where, after perching a few 

 moments, they attempted to fly, but every bee observed fell into the 

 grass only a few feet from the hive. During the later stages of ar- 

 senic poisoning a sick bee was usually drowsy and stupid, but often 

 acted "crazily " by continuously turning around ; then one or more 

 legs became paralyzed, and the bee could walk only in a staggering 

 manner, and could not fly ; a little later it became paralyzed to such 

 a degree that it could not get upon its feet, but could yet crawl about 

 by dragging its swollen abdomen ; it finally died in a state of coma. 



When installed in the orchard 1 hive of bees was weak, 8 were 

 strong, and 1 very strong. When transferred from the orchard 1 

 colony was slightly weaker than when it was brought there, 1 was 

 weak, 1 strong, and 7 slightly less strong than when placed in the 

 orchard. On June 15 the 2 Wentworth colonies experimented with 

 were dying rapidly; on June 25 they were nearly depopulated, and 

 on July 27 entirely so ; and 1 of Mr. Wentworth 's other 2 colonies 

 (not experimented with) was nearly depopulated. The bees from 

 the latter colony probably visted the sprayed orchards, for it was 

 only iy2 miles distant. In regard to the 8 bureau colonies, on June 



