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BULLETIN 1364, U. S. DEPAETMENT OF AGEICULTUEE 



of 0.0006 milligram of arsenic per bee. A second lot of 500 bees was 

 fed 0.5 milligram of Paris green in the poisoned candy, or 0.0004 

 milligram of arsenic per bee, and lived an average of 3.3 days, with 

 a minimum of 0.6 and a maximum of 7 days. A third lot of 500 bees 

 was fed 0.25 milligram of Paris green, or 0.0002 milligram of arsenic 

 per bee, and lived an average of 8.3 days, with a minimum of 0.6 'and 

 a maximum of 18 days. On analysis, 3 samples of these bees were 

 found to contain an average of slightly more than 0.0002 milligram 

 of arsenic per bee. A fourth lot of 500 bees was in the same manner 

 fed 0.15 milligram of Paris green, or a little more than 0.0001 milli- 

 gram per bee, and lived from 1 to 13 days, with an average of T. 

 Two samples of these bees were found on analysis to contain an aver- 

 age of 0.0002 milligrams of arsenic per bee. As a control, 1,000 bees 

 were fed nonpoisonous candy in confinement, and lived from 1.6 to 

 17.6 days, with an average of 9.8. Two samples of these were an- 

 alyzed and found to contain 0.0001 milligram of metallic arsenic per 

 bee. These experiments, with others of the same kind yet to be men- 

 tioned, are summarized in Table 7, with the results of analyses of 

 dead bees and other data. 



During this investigation many samples of bees, supposedly not 

 poisoned, were analyzed. Some were found to contain as much as 

 0.0001 milligram of arsenic per bee, others a trace, and still others 

 none at all. Since all animal tissue is said to carry at least a trace 

 of arsenic, 0.0001 milligram each of metallic arsenic may here be con- 

 sidered the maximum quantity carried by control bees. 



Table 7. — Simimary of results obtained Tjy feeding arsenicals to bees in observa- 

 tion cages, 1914 and 1920 



Substances fed bees in each experiment 



Number 



of bees 



fed 



Average 

 life of 

 bees 



after eat- 

 ing the 



arsenical 



Average quantity 

 of arsenic (As) — 



Fed to 

 each bee 



Found 

 per bee 



by 

 analysis 



Number 



of bees 



analyzed 



Nonpoisoned candy (control) 



Paris green in candy 



Do 



Do 



Do 



Acid lead arsenate in honey.. 



Do 



Do 



Do 



Arsenic acid in honey 



Acid lead arsenate In honey.- 



Sodium arsenate in honey 



Paris green in honey 



Do 



Do 



Zinc arsenite in honey 



Calcium arsenate in honey. . 



Poisoned pollen 



Nonpoisoned pollen (control) 



1,000 

 500 

 500 

 500 

 500 

 500 

 500 

 500 

 500 

 100 

 100 

 100 

 100 

 100 

 100 

 100 

 100 

 500 



1,000 



Days 

 9.8 

 .15 

 3.3 

 8.3 

 7.0 

 6.0 

 5.4 

 5.0 

 5.0 

 5.46 

 5.71 

 5.59 

 5.59 

 5.76 

 5.77 

 6.23 

 6.91 

 6.9 

 10.4 



Milligram 

 Trace. 

 0. 0008 

 .0004 

 .0002 

 .0001 

 .0010 

 .0007 

 .0005 

 .0003 

 . 00049 

 . 00049 

 .00049 

 . 00057 

 . 00057 

 .00057 

 . 00057 

 . 00049 

 . 00004 

 Trace. 



Milligram 

 0. 0001 

 .0006 

 .0004 

 .0002 

 .0002 

 .0009 

 .0004 

 .0004 

 .0004 



.0003 



Trace. 



60 



75 



50 



75 



50 



125 



100 



100 



50 



100 

 100 



A fifth set of 500 bees was fed 5 milligrams of paste lead arsenate 

 in honey, and lived from 0.3 to 21.3 days, with 6 days as an average. 

 Providing they ate equal quantities of the poison, each one took 

 0.0010 milligram of metallic arsenic. When analyzed, 5 samples 



