THE AMERICAN APICULTURIST. 



139 



8 p. M., 54.° Extreme temperature, 

 hottest, 98,° coolest 34.° 



For February, 7 a. m., 47,° i p.m. 

 in sun, 79,° 8 P. M., 53.° Highest 

 above 92,° lowest, 28.° 



Greatest variation during seven 

 hours, 58.° 



February at 7 a. m., temperature 

 only 7° colder; at i p. M. 1° hotter 

 and at 8 p. m., i° colder. 



January was very foggy and damp 

 and much more uniform in temper- 

 ature than February. 



Bees work every favorable day but 

 no swarming in this vicinity this 

 month. 1 



C. G. Ferris. 



Sauford, Fill., March 11, 1885. 



EXCHANGES. 



Limitation of the visual field 

 OF the worker honey-bee's ocelli. 

 BY THE REV. J. L. Zabriskie.^ — The 

 honey-bee is a remarkably hairy in- 

 sect. On the head the hairs are 

 dense, and of various lengths ; and 

 they cover every part, even the com- 

 pound eyes and the mandibles. The 

 antennae, however, are apparently 

 smooth, having only microscopic 

 hairs ; and a path through the long 

 hairs, from each ocellus, or simple 

 eye, directly outward, — to be de- 

 scribed more fully presently, — is 

 practically smooth. 



The ocelli are so situated that 

 when the ]:)ee is at rest and the face 

 vertical, they are directly on the top 

 of the head, arranged as an equilat- 

 eral triangle, and one ocellus is di- 

 rected to the front, one to the right 

 side, and one to the left^. 



1 By mistake this communication, which 

 should have appeared in our last, was ovei-- 

 looked and as it contains valuable items we 

 give it in this number.— Ed. 



^Tnis paper was read at a meetinnr of the 

 New York Microscopical Society, Alarch 6, 

 1885. 



3 Tlie ocelli are simple eyes or lenses, set 

 between the compound eyes, as adtlitional or- 

 gans of vision. These organs are possessed 

 by all insects which have compound eyes. 

 —Ed. 



Long, branching hairs on the crown 

 of the head stand thick like a minia- 

 ture forest, so that an ocellus is 

 scarcely discernible except from a 

 particular point of view ; and then 

 the observer remarks an opening 

 through the hairs — a cleared path- 

 way, as it were, in such a forest 

 — and notes that the ocellus, looking 

 like a glittering globe half immersed 

 in the substance of the head, lies at 

 the inner end of the path. The 

 opening connected with the front 

 ocellus expands forward from it like 

 a funnel, with an angle of about fif- 

 teen degrees. The side ocelli have 

 paths more narrow, but opening more 

 vertically ; so that the two together 

 command a field which, though 

 hedged in anteriorly and posteriorly, 

 embraces, in a plane transverse, of 

 course, to the axis of the insect's 

 body, an arc of nearly one hundred 

 and eighty degrees. 



These paths through the hairs ap- 

 pear to me to be indications that the 

 ocelli are intended for distant vision, 

 although the opinion that near vision 

 is their function is held by eminent 

 opticians. 



The ocelli are nearly hemispherical, 

 and the diameter of each is about 

 fifteen times that of a facet of the 

 compound eye. Such a form of lens 

 would, I will concede, indicate for 

 these organs a short focus, and 

 hence, a fitness for near vision. 



But if the ocelli are intended for 

 near objects, it is difiicult to under- 

 stand why they are surrounded by a 

 growth of hair so dense as to per- 

 mit unobstructed vision only in a 

 very narrow field, and why they are 

 so placed on the top of the head as 

 to be debarred from seeing any ob- 

 jects in the neighborhood of the 

 mandibles and the proboscis, the 

 ability to see which objects would ap- 

 pear to be very necessary in the con- 

 stant and delicate labors of the 

 worker honey-bee among' the flow- 

 ers. 



Dr. Zabriskie exhibited the head 



