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am ll 
to visit such blossoms, almost to the exclusion of normal blossoms. 
On examination, he found that the nectaries on apricot blossoms were 
30 deep down in the cup surrounding the pistil that they were not re- 
moved when the blossoms were emasculated, and that the removal of the 
upper part of the blossom apparently made the nectaries of such easy 
access that bees preferred to visit the emasculated blossoms. This was 
a) et 
not true of such blossoms as the almond, in which the nectaries, being 
high up in the cup, are removed with the petals. This discovery upset 
some of the plans of the University workers on pollination and made nec- 
essary the bagging instead of emasculation of certain blossoms which 
they desired to hand pollinate. Emasculated nectarine and peach blos— 
soms were also worked by bees for nectar." ’ 
Pan American Union requests bee manvscript.--In Mar h a manuscript 
by Jas. I. Hambleton, entitled, "Beekeeping in the United States," was 
_ Submitted to the Editorial Office for approval. This manuscript was 
prepared upon the request of the Director General of the Pan American 
Union for publication in its Spanish Bulletin. 
FRUIT AND SHADE TREE INSECTS 
Cockroaches react to poisen pillg.-~E. H. Siegler and Francis Mun- 
ger, Takoma Park, Md., have devised a method of testing stomach poi- 
sons, using Periplaneta americana L. as a test insect and feeding the 
poison in pills of gelatine. By this method known quantities of the 
poison to be tested are incorporated in a layer of gelatine one-eighth 
inch thick. By means of a cork borer, pills of a definite volume are cut 
out from the gelatine so that the quantity of poison consumed may be 
estimated with a fair degree of accuracy, placing the tests on a semi- 
quantitative basis. The results of tests conducted during the month 
of March indicate that sodium fluoride is not so toxic as a stomach poison 
to the cockroach as is lead arsenate. For example, during the above 
reriod the roaches feeding on sodium fluoride consumed slightly more 
than three times the quantity consumed by the roaches, feeding on lead 
arsenate. The lead arsenate killed 75 per cent of the roaches, where— 
as the mortality with sodium fluoride was zero However, sodium fluo- 
ride is effective as a stomach poison when consumed in larger quanti- 
ties, Rotenone, although used in a very high concentration for this 
compound and consumed in larger quantity than the arsenical and fluo- 
ride, gave no mortality. 
Proof that sodium fluoride kills roaches by contact.—-Mr. Munger 
has devised an effective method of determining the contact effect of 
certain materials against the cockroach, as distinguished from the ac- 
tion of the same materials as stomach poisons This method consists 
of isolating the head from the remainder of the insect by the use of 
@ thin rubber dental dam, In tests with sodium fluoride, death fol- 
lowed within a few hours when the cockroaches were placed in vials con- 
taining small quantities of the powder. The head was left in such a posi- 
+ion that none of the material could have been taken internally. Insects 
similarly collared in clean vials did not die. 
