270 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 12 



solution showed large numbers of highly refractile oval bodies strongly resembling 

 the spores of Nosema apis, the microsporidian parasite sometimes associated with 

 adult diseases of bees. 



To determine whether any of these spore-like bodies might be present in the honey 

 of the colony from which the dead bees were taken, several square inches of comb, 

 containing sealed cells of honey but no apparent pollen cells, were cut from the frames 

 and the honey was squeezed therefrom through cheesecloth. This honey was a clear 

 dark amber color having a peculiar somewhat bitter flavor and a disagreeable odor. 

 On standing a yellow scum came to the surface, containing a large amount of pollen. 



Several grams of this honey were dissolved in about 30 cc. of distilled water and 

 centrifuged. Microscopic examination of the residue under a cover glass in a water 

 mount and with the high power dry lens, showed what was apparently a large number 

 of Nosema apis spores and also many unidentified pollen grains of various shapes, 

 large round ones predominating however. After accidentally crushing some of these 

 pollen grains under the cover glass it was found that several of the large round fairly 

 smooth grains seemed to be packed full to overflowing with these refractile spore-like 

 bodies. Also the microscopic field had become crowded with countless numbers of 

 these bodies. 



A second lot of honey was treated in the same manner, only this time the residue 

 was washed several times with salt solution. Microscopic examination showed the 

 same appearance particularly after crushing with the cover glass. 



Next, pollen from cells in the comb from which the honey had been taken was 

 examined in a water mount in the same manner. These same spore-like bodies were 

 found to be present only in much smaller numbers until the pollen grains were crushed 

 as before when the spore-like bodies again appeared in large numbers. 



Pollen grains from combs taken at random from several different sources were 

 then examined but no such appearance was found in any of the samples examined. 



Stained smears from the intestinal contents of the dead bees and also from the 

 residue after centrifuging the diluted honey gave no results as these bodies seemed 

 to have disappeared or been destroyed during the process of staining. Finally, some 

 Gram's iodine solution was run in under the cover glass of a water mount of some of 

 this material. Almost immediately these spore-hke bodies turned a deep purple 

 color and the pollen grains containing them turned almost black giving what appeared 

 to be a typical starch reaction. It was then found, aided by the kindness of the pollen 

 laboratory of the H. K. Mulford Company of Glen Olden, Pa., that these pollen 

 grains were from corn and that although this is the most striking example of the 

 presence of starch granules in pollen grains, most of the cereal grains show the same 

 condition, but they are not found in pollen of other families. 



These starch grains upon measurement and comparison with the size and appear- 

 ance of the actual Nosema apis spores were found to have just about the same meas- 

 ui'ements and shape although the shape of starch grains was a little more variable, 

 often being more nearly round than the t^-pical long oval. 



Furthermore, it has been found experimentally that such materials as starch and 

 dextrin are indigestible to bees, causing what might be called acute indigestion or 

 auto-intoxication. Therefore, the presence of so much indigestible starch in the 

 pollen food of the bees was probably a contributory factor if not the actual cause of 

 the dysentery and death of so many of the adult bees in this particular instance cited. 



Starch granules have since been found in a few samples received for examination. 

 Therefore, it has since then been the custom after making a preliminary microscopic 

 examination, to treat with iodine solution in the above manner all material from 

 samples sent in for diagnosis of adult diseases, in order to prevent possible future 

 confusion. This precaution should be taken in all such examinations. 



Arnold P. Sturtevant, Bureau of Entomology. 



