﻿EFFECTS ON HONEYBEES OP SPEAYING FEUIT TREES 25 



of them were found to contain an average per bee of 0.0009 milligram 

 of metallic arsenic (Table 7). A sixth set of 500 bees whs fed 3.5 

 milligrams of lead arsenate, or 0.0007 milligram each of arsenic, and 

 lived from 2 to 10.7 days, with an average of 5.4. When analyzed, 

 4 samples of them contained only 0.0004 milligram of arsenic as an 

 average per bee. A seventh set of 500 bees was fed 2.5 milligrams 

 of lead arsenate, or 0.0005 milligram of arsenic each. They lived 

 from 0.8 to 12 days, with 5 days as an average; when analyzed, 4 

 samples of them contained an average of about 0.0004 milligram of 

 arsenic per bee. An eighth set of 500 bees was fed 1.5 milligrams 

 of lead arsenate ; if they ate equal quantities of the poison, each one 

 took 0.0003 milligram of arsenic. When analyzed, each of 2 samples 

 of these dead bees contained 0.0004 milligram of arsenic per bee. 



For several days after the trees in the orchard at Winthrop, Me., 

 had been sprayed in May and early June, 1914, poisoned pollen was 

 stored in the hives. One of the bureau hives returned to Washington 

 in June became depopulated August 1. To ascertain if the combs 

 in this hive still contained poisoned pollen, 10 grams of the pollen 

 were removed and were thoroughly mixed with 40 grams of honey. 

 This mixture was then fed to 500 bees, as usual. They lived from 

 0.6 to 14.6 days, with 6.9 days as an average, whereas 1,T)00 control 

 bees fed nonpoisoned pollen lived an average of 10.4 days (Table 7). 

 When analyzed, 2 samples of pollen from the same combs were found 

 to contain 2.57 parts and 1.19 parts of arsenic per million, the average 

 being onl}^ one-fifty-first as much arsenic as was found in fresh pol- 

 len stored in the combs only a short time after it was collected from 

 the sprayed trees. If the 500 bees ate equal quantities of the arsenic 

 fed to them, each one took 0.00004 milligram of it, and this small 

 quantity would not have noticeably affected them. When analyzed, 

 1 sample of the dead bees was found to contain 0.0001 milligram of 

 arsenic per bee, each of 2 samples 0.0002 and 1 sample 0.0006 milli- 

 gram, making an average of 0.0003 milligram of arsenic per bee 

 (Table 7). It is thus seen that the small amount of arsenic still 

 contained in this pollen was not equally eaten by the bees, and there- 

 fore the combs containing it should not be used again. 



In June, 1920, eight arsenical spray mixtures were so prepared 

 that they contained equal contents of arsenic acid or arsenious acid. 

 A small portion of each of these was diluted 20 times, and 1 cubic 

 centimeter of this dilution was thoi-oughly mixed with 4 cubic centi- 

 meters of honey in one of the small feeders. Providing the poisons 

 were homogeneously mixed, each feeder contained 0.038 milligram of 

 arsenic acid or arsenious acid; and, if the 50 bees in each feeder ate 

 an eqind share, each bee took nearly 0.0005 milligram of metallic 

 arsenic when the arsenic, acid or the arsenates were eaten, or 0.00057 

 milligram when the 3 mixtures of Paris green and the zinc arsenite 

 were eaten. This series of tests was made a second time. Of these 

 8 arsenicals, the arsenic acid was most toxic (Table 7), but the 

 soflium arsenate and 1 preparation of l*aris green wci-e close seconds, 

 anrl the powdered acifl hiud ars(!nate third; the average life of bees 

 after eating (he '5 mixtures of Pai'is gre(!n is exactly the same as that 

 of those (waling flic lead ai'serialc. Tiic y.'wu- ai'scnilc and calciinn arse- 

 nate seemed considerably less loxic, probably b(^cause the bees did not 

 eat the mixtun^s cojitaining them as readily as they did the others. 



