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69.11.856:67.99 



CONTRIBUTIONS FROM THE ZOOLOGICAL ];,ABQRATORY QP THE 
MUSEUM Ot QOMPARATIVE ZpOLO0T AT 
HARVARD COLLEGE." 



No. 321. 

THE :gLATiON OF PHOTOT^aPISM TO SwABMING ; IJf 
-^HE HONEMSiE, APIS^ MELLIFERA L. 



By iJwiaHT E. Minnijoh. 



FttOM Tfiji ;JOWRKAC OP J'STCHOBI^XOiG'T, Vot. II, N^.% 



CAMBBlpdii, AiASS.f iu. S. A. 



59.11.856:67.99 



CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE 

MUSEUM OF COMPARATIVE ZOOLOGY AT 

HARVARD COLLEGE. 



No. 321. 

THE RELATION OF PHOTOTROPISM TO SWARMING IN 
THE HONEY-BEE, APIS MELLIFERA L. 



By Dwioht E. Minnich. 



Fkoh the Journai. op Psychobiologt, Vol. II, No. 2. 



CAMBRIDGE, MASS., U. S. A. 
April, 1920. 

li 



Beprinted from Pstohobiolooy, 
Vol. II, No. 2, April, 1920 



THE KELATION OF PHOTOTROPISM TO SWARMING 
IN THE HONEY BEE, APIS MELLIFERA L.> 

DWIGHT E. MINNlCfl 

The honey bee is remarkable for the extent to which many of 
its activities are controlled by light. Observations and experi- 
ments demonstrating the strong photopositive responses of this 
animal have been detailed by Lubbock ('82, p. 278, 279, 284), 
Graber ('84) and Hess ('13 a, '13 b, '17) . And indeed this feature 
of behavior must have been patent to many of the earlier workers, 
so strikingly and constantly is it exhibited. 

While conducting some experiments on the photic behavior of 
bees several years ago, I was greatly impressed by the strong, 
positive reaction to light which normal individuals almost 
invariably displayed. Bees in an active state of locomotion, or 
"easily excited to such, exhibited an orientation which, for its 
rapidity of accomplishment and its accuracy of maintenance, 
was most spectacular. I say bees exhibiting vigorous locomo- 
tion, for, obviously, bees which are torpid and do not move 
freely — a condition frequently encountered during cool, damp 
weather — cannot show phototropism. Even the moribund con- 
dition seemed often to intensify rather than to weaken photic 
behavior, and bees scarcely able to creep were observed making 
a final struggle toward the light. 

My experiments were carried on well into the autumn, when 
it became more and niore difficult to obtain bees in the field as 
the flowers became less abundant. I, therefore, installed a 
single comb of worker bees without queen, in a glass observation 
hive. The hive was kept darkened by means of small wooden 
covers fitted to the glass sides, and the exit was covered with 
a bit of screen wire to prevent the escape of the bees. Animals 

1 Contributions from the Zoological Laboratory of the Museum of Comparative 
Zoology at Harvard College. No. 321. 

177 



178 DWIGHT E. MINNICH 

could be kept in this way in reasonably good condition for a 
month to six weeks, food being provided in case there was not 
sufficient in the comb. It was on these bees that I made the 
observations to be detailed in the present note, which I believe 
afford some evidence oil the question of swarming and its rela- 
tion to light. 

The strong positive phototropism of individual bees is also 
characteristic of certain activities of the hive as a whole. Kellogg 
('03) was the first to call attention to the fact that swarming 
bees are strongly positive to light. He says (p. 694), "That 
the issuance from the hive at swarming time depends upon a 
sudden extra development of positive heliotropism seems obvious. 
The ecstasy comes and the bees crowd for the one spot of light 
in the normal hive, namely, the entrance opening. But when 
the covering jacket^ is lifted and the light comes strongly in 
from above — ^my hive was under a skylight— they rush toward 
the top, that is toward the light. Jacket on and light shut off 
from above, down they rush; jacket off and light stronger from 
above than below and they respond like iron filings in front of 
an electro-magnet which has its current suddenly turned on." 
These observations leave no doubt as to the strong positive photo- 
tropism of swarming bees. The statement, however, that the 
issuance of the swarm is dependent upon a "sudden extra develop- 
ment" of positive phototropism has met with some difference of 
opinion. 

Thus von Buttel-Reepen has objected to this interpretation 
oil the ground of a particular swarm instinct. He says ('15, 
p. 168)". ... so ist in diesen Momenten [the emergence 
from the hive at swarming] nicht ein besonders starker Helio- 
tropismus die Ursache, sondern die Schwarminstinkte • drangen 
die Bienen in das Freie." Another objection, and I believe a 
much more important one, is suggested by a statement of Hess 
('13a, p. 663). "Meine Versuche zeigen, dass die Neigung der 
Bienen, zum Hellen zu gehen, nicht auf die Zeit des Hochzeits- 
fluges beschrankt ist." This contention of Hess— that the 

' Kellogg had a glass observation hive covered with a black cloth jacket. 



RELATION OF PHOTOTROPISM TO SWARMING IN THE BEE 179 

manifestation of photopositiveness is not confined to any given 
period, such as the nuptial flight, has been amply confirmed in 
my observations. I have already called attention to the fact 
that among individual bees an active animal exhibits, almost 
without exception, strong positive phototropism. Large aggre- 
gates of bees also show marked positive light reactions quite 
aside from swarm activities, as the following observations clearly 
show. 

The glass observation hive with its single comb of bees was 
situated at a south window where it was exposed to the sun 
during the morning hovirs. With the oncoming of the cool days 
of late October and early November, the bees became much less 
active. On bright days, however, the exposure to the warmth 
of the sun, and the corresponding rise of temperature within the 
hive, served to activate the colony until most of the bees were 
moving about the walls of the hive in a rapid uneasy manner. 
If at such a time the cover was removed from the end nearer 
the window, thus admitting the light, there was with the first 
penetrating rays, a sudden increase of the hvim within. There- 
upon ensued a scene no less spectacular than that described by 
KeUogg ('03, p. 693). His words picture it exactly, ". . . . 
the whole community of excited bees flowed — that is the word 
for it, so perfectly aligned and so evenly moving were all the 
individuals of the bee current — ," toward the illuminated side. 
A few hours later, however, when the sun had passed from the 
hive and the temperature had fallen, particularly on the cooler 
days, the uncovering of one end of the hive elicited no such 
response. With perhaps the exception of a very few individuals, 
the bees remained quietly in the swarm cluster. Nor was this 
failure to obtain a, response a result of the lowered intensity of 
light, for the active worker bee responds to a fairly low intensity. 
It must, therefore, have been due to the difference in temperature. 

These facts, together with those previously stated, demon- 
strate conclusively that the pronounced phototropism, so con- 
spicuous in swarming bees, is not confined to the period of 
swarming. This condition of photosensitivity appears to remain 
fairly constant at all times in the animal, although active locomo- 



180 DWIGHT E. MINNICH 

tion and the absence of other strong, distracting stimuli are 
necessary to its demonstration. The situation here differs 
from that described by Loeb ('90) for winged male and female 
ants, in which positive phototropism is confined exclusively to 
the period of the nuptial flight. 

We may agree with Kellogg, therefore, that the issuance of 
bees from the hive at swarming may be a simple exhibition of 
positive phototropism, but it is not the result of a sudden increase 
in phototropism. The sudden increase is in the activity of the 
animals. Consequently, the fundamental factors in swarm 
behavior are those which effect a condition of heightened ac- 
tivity, a condition in which locomotion is generally controlled 
by light. In my own observations the state of heighteined activity 
doubtless arose from the conditions of temperature and the pre- 
ventioli of the bees from making their accustomed flights for 
defecation, etc. The factors which activate the swarm are not 
known. They iliay consist of particular swarm instihcts, as 
von Buttel-Reepen ('15) has suggested, or they may even be 
more simple reflexes of as yet unknown nature. In any case, 
the evideiiiee seems clear that, although phototropism may bte 
an important featiu-e of swarm behavior, it is neither peculiar 
to this slctivity nor the primary causal agent of it. 

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CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF 
THE MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD 
COLLEGE. (Continued.) 



E. L. Mabe, Director. 

•»• Abbreviadons used : — 

B.M.G.Z for BnU. Mus. Comp. ZoSl. 

!"• A. A for Proceed. Amer, Acad. Arts and 8ci. 

P.B.S.N.H. forProceed.Bo»t.Soc. Nat. Hist 

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CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF 
THE MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD 
COLLEGE. (Oontinued.) 

300. Pabkeb, Q. H. — The Activities of Corymorplia. Jour. Exp. ZoBl., 24 (2) ; SOS- 

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Apis mellifera L. Jour. Psychobiol., 3 (2) : 177-180. April, 1920. 



dOllf JtlBtJtiONlpi; JROM THB ZOOJ.Q<SI<3AL LABORATORY OF 
THB MPSEUM OF COMPARATIVE ZOOLOGY AT iUaVABD 

•' OOiSJi^tXBi. (Oontinued.y 



E. X. MjMK, I>iftctor:' 



9.H.6.Z. • . . > . . ., . . . fej: Bnli. Miia. Comp. Zi»W. 

P. A. A. », . f., . , . . . . for PrOcead. Aimer. Acad^. Aria and Sci. 

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Now.*- C»p&<i^tt«;zirt o/;(ftn«rt*»f«on.,:if^ 

■■;';. !,-.■''■/ ;■, ,!., ' tint Oft ^ppifixftCon. '-■•' ," 

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-- ;; -■•405t;i2&^ pM.,'iw^^; ■;.,-■ -■;■■'';::■--■'''"■/"'/, ', •■ .•,,' --V-, 

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,;■'■', Jivl.AipfetraiSiiii3'J%sj0lC«4.M)4;#S3^9:; •^o%.,'i.i%' '[■'"■ j;_,'"-\ ;j!:\3^'^" '> 
'>298." ;T?AEiK«!ft,,Gl'Mi>-:-.TheJPp\i;ej-.isf Sifc^^ ,^ea.A^eWiie.C3r|jrin»y 'f^ ' 



'■■■Zp<|I;i,»4i(2K2l9-|S..;,i%:fi9i7,^^^ "N-VA^C'. :lf4::,,'y- '■'"'''f' '""' -t'! 



CONTBIBUTIONS FliOM TliE ZOOLOGICAL LABORATOBY OF 
THE MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD 
COLLEGE, ^Continued.') 

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331. Nov., 191T. - : \^ ;^ '"-' ' ' - • '■ ' 

301. Stbingeb, O. E.-^Tlie Means of hocbtaoMoa in Planaiians, Proc. Nat. Acad. 

Sci., 3 (12): 691-692. Dec., 1917. _, • : , 

•302. Olmstbd, J. M. D.— The Eegeneration of Triangular Pieces of Planaria maoUlata." 
A Study in Polarity. Jonr. Ej^. Zool., 85 (1) :167-176. --Feb.^MlS. ■, _ " , 
303. ( HSoHT, S. — Tlfe Physiology ofiAsordia atra Lesueuif. I^ General Physiology. , 
304.1 H. Sensory Physiology. Jour.Exp. ZoBL, 25 (1) :229-2S9. Feb., 1918. 
«)6. HBCtffiI!,S. — Iii. III. TheBlood System.- Amer.Jour.Pllysiol.,45(S):167-187. 

■ ■ Feb., Wis. ■;--. . ■"' - - - , ' ■:"' - \ ' ' . 

306. Brat, A. W. L.^The Seactipns of the Mclanophores of Amiurus to Light and 

Adrenalin. Proc. Nat. lead. Sol., 4(3) : 6840, Mar.;i918f , ;; i 

307. WaltOm, A. C— The Oogenesis and Early Embryology of ^scarfs leapis Werner. - 
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Commbh Catfish, Amiurus nebulous, (LesuearV Amdr. Jour. Phyd'ol., 40 
J5)':448-458. Aug., 1918. "-■ ' ^ i v ~" 

309. ESDriBLO, A. C — Ihe Piiysioitogy of the Melanophores ol the Hgrtied Toad, ' 

Phryjspsoma.' Jour. Exp. Zo91.,a« (2): 276-33^. July, 1918. ' >' , ' 
810. BBOOKS.'E.S. — Keiptibns of Frogs to Heat and Cold,. Amer. Jour. Physiphi _ 
,"40 (6) .-493-601. Aug., 1918. • ^; • V> ' ' - ' '' 

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47 <2): 265-277. Not., 1918. .^^ ~^ '" > i' ' \ ? 

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JoUrrGei.PhysioJ.^1 (2)^231-^36." NoT.i 1918. ,; '' 

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Exp.^ool., 27 t3):391-S96. Jan., 19M< ,.... '•-':. 7'} ' 

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■•, 30(2):2l74227,ipl. Feb.,1919.",_ ,' "if-"" , -' - '" ' " ^ 

316. Parker, G.H.-trThe Organization- of KenJUa.' Jour. Exp. Zool., 37 (4):499- 

607. Feb., 1919.,^ "- - - ' ."^ ' ... - - , , -''^ 

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^-. 669-681, 1 pi.- Apr., 1919. ■' ' :., .-..^ : .- -C 

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,7^ Verrill. Jour. Exp. -Zool., 38 (2)^161-204.^ .May,,1919. ' ^^ 

sis. PaSkbr, G. H. — The Effects of- the" past Wintet on tlie '0(fcurrence of SagMtia ? 
-- - luciae Verrill. . -Amer.Nat.,-5i"'(626):280-5J81. MiyrJune, 1919. i > -'''^ 

320. MiHNioH, p. E.— The Photic Keactions of the-Honey-Bee, Apia ineilifera L. 

Jour.':R3ip. Zool., 39(3) ;348'-426.' .koT., 1919. I -; , . ' '" 

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Apis mellifera L. Jour. Psychobiol., 3 (2) : 177-180. April,1920. 



59.11.856:57.99 



CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF THE 

MUSEUM OF COMPARATIVE ZOOLOGY A^ 

HARVARD COLLEGE. 



No. 320. 

THE PHOTIC EE ACTIONS OF THE HONEY-BEE, APIS 

MELLIFEEA L. 



Bt Dwight B. Minnich. 



From the Journal of Experimental Zoology, Vol. XXIX, No. 3. 



CAMBRIDGE, MASS., U.S.A. 
November, 1919, 



AtJTHOR'B ABSTRACT OF THIS PAPEK ISSUED Reprinted frOm ThE JOURNAL OP EXPERIMENTAL 

BY THE BIBLIOGRAPHIC SERVICE, SEPTEMBER 29 ZoOloqy, Vol. 29, No. 3, November, 1919 



THE PHOTIC REACTIONS OF THE HONEY-BEE, APIS 

MELLIFERA L.i 

DWIGHT E. MINNICH 

SEVENTEEN FIGURES 

CONTENTS 

I. Introduction , 343 

II. Literature 344 

III. Apparatus and methods 350 

IV. Material 358 

V. Behavior of normal bees 360 

VI. Behavior of bees with one eye blackened 371 

VII. Variability of photic response 391 

VIII. Nature of photic orientation 403 

IX. General summary and conclusions 410 

X. Bibliography 412 

XI. Appendix 415 

I. INTRODUCTION 

The circus movements produced by blackening one eye in cer- 
tain arthropods have long been familiar to zoologists. It was 
not, however, until the advent of more recent interpretations of 
behavior, that they received any considerable attention. Then 
for the first, the significance of their relationship to normal orien- 
tation was recognized. It became apparent that the nature of 
the stimulus involved in the two cases was the same. Obviously, 
therefore, the application of any general theory of photic orien- 
tation to those forms in which circus movements occurred de- 
pended upon its ability to explain this phenomenon satisfactorily. 
This consideration has led, within the last few years, to a number 
of more or less extensive investigations of these reactions. 

When the present researches were begun there had been no 
attempt to study circus movements quantitatively. During the 

1 Contributions from the Zoological Laboratory of the Museum of Compara- 
tive Zoology at Harvard College, no. 320. 

343 



344 DWIGHT E. MINNICH 

progress of the experiments, however, DoUey ('16) has published 
a contribution to this phase of the subject. His methods as well 
as his results, on Vanessa, differ widely from those to be de- 
scribed for the honey-bee. Although in his experiments, as in 
mine, the illumination employed is defined as non-directive, it 
was very unlike in the two instances. The results obtained by 
DoUey are described in terms of circus movements of greater or 
lesser 'angles of curvature;' those obtained by the writer, in terms 
of degrees turned per centimeter. The conclusions drawn in the 
two papers are also widely divergent. 

Tt is a pleasure here to acknowledge my deep indebtedness to 
Dr. G. H. Parker, at whose suggestion this research was under- 
taken and with whose helpful criticism it was carried on. T wish 
also to express my gratitude to Dr. E. L. Mark for the courtesies 
and privileges of the Zoological Laboratory. 

II. LITERATURE 

As early as 1796, Goeze^ (p. 42) recorded the fact that a hornet 
in which one eye had been painted over with an opaque varnish 
always flew toward the uncovered eye. Some years later, Tre- 
viranus ('32, p. 194) described an experiment in which the lower 
half of the right cornea of a dragon-fly was carefully cut away 
from the optic nerve, with the result that the animal moved toward 
the left side. 

Decidedly the most interesting of the earlier observations are 
those of Dubois ('86) on a phosphorescent elaterid beetle of the 
genus Pyrophorus. This insect responds positively to at least 
certain intensities of light, and according to Dubois (p. 209) it 
is most affected by the yellow-green rays, which also predominate 
in the spectrum of its own light. The photogenic organs are three 
in number, one occupying a median ventral position on the first 
abdominal segment, the other two being situated on opposite 
sides of the prothorax near its dorsolateral edges. Whenever 
the beetle begins to creep spontaneously in the dark, the pro- 
thoracic organs become luminous. During flight the abdominal 
organ does likewise. 

' I have not had direct access to this work. The above reference is taken from 
a footnote m Treviranus (32, p. 193). 



PHOTIC REACTIONS OP HONEY-BEE 345 

Dubois (p. 208) found that upon completely obscuring the 
light from the prothoracic organ of one side of the body with a 
covering of black wax, the beetle no longer crept in a straight 
line. Smoked paper records, made in a dark room, showed that 
such individuals crept in circles toward the functional eye. A 
check experiment, moreover, showed that the results obtained 
were not due to the weight of the wax. If instead of eliminating 
one of the prothoracic organs, the cornea or the entire eye of one 
side was destroyed with a red-hot needle (p. 211), very similar 
results were obtained. When, however, both photogenic organs 
of the prothorax were obscured or both eyes were destroyed, the 
animal crept in a hesitant, irregular fashion, presently stopping 
altogether. 

Dubois has interpreted these results from an anthropomorphic 
viewpoint, as evidenced by his original paper and by a more 
recent comment ('09). To the present writer, however, these 
responses of Pyrophorus afford not only a typical case of circus 
movements, but one of considerable theoretical importance as 
well. The tendency to circle attendant upon the suppression of 
one photogenic organ or the destruction of one eye may be attrib- 
uted to the unequal stimulation on the two sides of the body. 
If this be correct, the case is indeed unique, for the beetle is ori- 
ented by its own luminosity. This, of course, in nowise affects 
behavior in the normal animal. With a photogenic organ on 
each side of the prothorax producing light of the same quality 
and intensity, it is always perfectly oriented with respect to its 
own light. But if the source of light or the photoreceptor of one 
side be eliminated, the beetle promptly orients toward the oppo- 
site side, the side which is receiving the greater stimulation. 

In recent years, a steadily increasing number of arthropods 
have been shown to exhibit circus movements when one eye is 
blackened or destroyed. The researches of Bethe ('97 a), Axen- 
feld ('99), Hohnes ('01, '05), Rddl ('01, '03), Parker ('03), Had- 
ley ('08), Carpenter ('08), Brundin ('13), Hohnes and McGraw 
('13), DoUey ('16), and Garrey ('17), have demonstrated conclus- 
ively that among phototropic arthropods generally, unilateral 
photic stimulation results in a more or less asymmetric response. 



346 DWIGHT E. MINNICH 



These investigations have covered between fifty and sixty spe- 
cies, including the four chief classes of arthropods. Among the 
insects, where most of the work has been done, representatives 
of most of the larger orders have been experimented upon. These 
embrace Orthoptera, Blattoidea, Hymenoptera, Coleoptera, 
Odonata, Lepidoptera, Diptera, Homoptera, and Hemiptera. 
The phenomenon of circus movements — or perhaps better, asym- 
metrical response — must, therefore, be regarded as general rather 
than exceptional for the members of this phylum. 

The form of response naturally varies with the peculiarities of 
locomotion in a given species. It is not the same for a sidewise 
moving crab, such as Carcinus, as it is for an insect which moves 
forward. With the usual type of forward locomotion, however, 
arthropods with one eye blackened generally circle toward the 
functional eye, if they are positively phototropic ; toward the non- 
functional eye, if they are negatively phototropic. 

It is true there are cases which, on first examination, do not 
appear to conform to this generalization. Thus Holmes ('05, pp. 
332-336) has demonstrated clearly that an animal with one eye 
blackened may at first perform circus movements in creeping 
toward a hght, only to modify its behavior after a time and creep 
in a straight path. Such was true of both Ranatra and Noto- 
necta. Axenfeld ('99, p. 375) had previously made similar 
observations, and more recently Brundin ('13, pp. 337, 346-348) 
and DoUey ('16, pp. 371-382) have demonstrated the same phe- 
nomenon in the species with which they worked. 

There can be no doubt, therefore, that many arthropods with 
one eye blackened are able in time to modify their behavior to 
hght. This, however, in nowise lessens the significance of the 
initial tendency of the animal to perform circus movements. In 
fact, this initial tendency is the all-important one as far as the 
question of orientation in the normal animal is concerned I do 
not believe, therefore, that the presence of modifiability in an 
animal warrants considering its behavior as an exception to the 
general occurrence of circus movements. 

A second difficulty in the way of any generalization concerning 
circus movements has been encountered in the behavior of cer 



PHOTIC REACTIONS OF HONEY-BEE 347 

tain flies. Thus Rddl ('03, p. 62) says, "Die Calliphora vomi- 
toria bewegt sich fast ebenso gerade mit einem geschwarzten Auge, 
wie wenn sie aus beiden sieht, und es ist mir nicht leicht, diese 
Erscheinung zu erklaren." Carpenter ('08, p. 486) states that 
Drosophila with one eye blackened "crept in a fairly direct path 
toward the light, although a tendency to deviate toward the 
side of the normal eye regularly occurred." It is possible, I 
believe, to interpret these cases as merely more extreme instances 
of modifiability, in which regulation occurs very rapidly instead 
of after a more or less prolonged experience. 

That modifiability is operative, at least in the case of Droso- 
phila, is evidenced by the following statement of Carpenter (p. 
486) . "The tendency to diverge from the direct path toward the 
side of the uncovered eye was overcome by a series of short, quick 
turns in the opposite direction, which kept them headed toward 
the hght." Further evidence in the case is afforded by the be- 
havior of one fly which, according to Carpenter, persisted in per- 
forming circus movements. This fly, however, (p. 486) "had 
long been active, and showed signs of fatigue." As will be shown 
later, very similar phenomena were observed in the honey-bee. 
In conditions, such as that of weakness, induced by long 
experiment, the bee frequently circled much more toward the 
functional eye than it had formerly done. It seems probable 
that in such states the animal approximates more nearly to a, 
simple, reflex behavior. Factors effective in modifying behavior 
in the vigorous animal have ceased to be operative. 

If these interpretations be correct, the conspicuous absence of 
circus movements in Drosophila. is only an extreme case of modi- 
fiability, and offers no real objection to the general conclusion to. 
be drawn from these reactions. However, further work is neces- 
sary upon both Drosophila and Calliphora before they may be 
disposed of with certainty. 

Responses of still another kind have seemed perhaps the most 
formidable obstacle to any general conclusion as to the occur- 
rence of circus movements. Thus Hadley ('08, p. 197) has shown 
that whereas the 'progressive orientation' of the lobster larva 
after the blinding of one eye is positive, the larva performs circus. 



348 D WIGHT E. MINNICH 

movements or turns toward the injured side. Brundin ('13, p. 
346) states that in positive specimens of Orchestia traskiana, cir- 
cus movements will occur as often toward the blackened as 
toward the normal eye, while Hohnes and McGraw ('13, p. 370) 
report the case of a positive skipper butterfly which almost inva- 
riably circled toward the blackened eye. 

A very plausible explanation of these apparent anomalies, 
however, has been offered by DoUey ('16, pp. 394-399), who has 
shown that the contact stimulus afforded by the material cover- 
ing the eye is sufficient to cause Vanessa, when in the dark, to 
turn continuously toward the covered eye. This tendency, more- 
over, exhibits little, if any, modification from day to day. The 
effect of such a contact stimulus is continuous. But in the pres- 
ence of photic stimulation of moderate or high intensity, it is quite 
overwhelmed by the strong phototropism of the butterfly. In 
the case of animals of less certain phototropic index, this contact 
stimulus is, in all probability, frequently strong enough to over- 
come the effect of light. An examination of the cases cited above 
shows that the phototropism of these animals is not of the une- 
quivocal kind exhibited by Vanessa. It seems likely, therefore, 
that their apparently exceptional behavior was due to contact 
and not to photic stimulation. 

Suppressions of photic circus movements by responses to other 
stimuli are not surprising, when it is recalled with what facility 
even the stereotyped circus movements produced through uni- 
lateral lesions of the central nervous system may be altered in a 
similar manner. Thus Bethe ('97 b, p. 507) states that the ten- 
dency of bees to circle toward the normal side after the removal 
of one half of the brain or the severance of one of the oesophageal 
commissures, may be arrested, and the animal may even be com- 
pelled to deviate toward the injured side by stimulating the legs 
of the normal side. Moreover, in a general statement concern- 
ing the several crustaceans and insects subjected to similar opera- 
tions (p. 541), he says, "... nach Aufhebung der Hem- 
mung der gesunden Seite durch angebrachte Reize aber auch 
spontan bei alien Versuchsthieren gerader Gang und Kreisgang 
nach der operirten Seite eintritt." 



PHOTIC REACTIONS OP HONEY-BEE 349 

Whether the effect of contact stimulation also accounts for 
certain of the phenomena observed by Axenfeld ('99) is not so 
clear. Axenfeld reports that nocturnal lepidoptera with one eye 
blackened turned toward the blackened eye during the day. In 
the same paper he makes the following general statement: "En- 
fin on peut observer que ces m^mes animaux photofuges, qui tour- 
nent en pleine lumilre du soleil du c6te de I'oeil convert, off rent 
le mouvement contraire au soir ou meme de jour, quand ils sont 
transport's dans une chambre mal 6clair6e; . . ."It 

may be that such animals, being attuned to a low intensity, re- 
spond positively to it, whereas a stronger intensity evokes a nega- 
tive reaction, somewhat according to the idea of Davenport ('97, 
p. 197). Certainly, if the circling of the nocturnal lepidoptera 
toward the covered eye was a hght response, it is not in harmony 
with the statement of Loeb ('90, p. 51) to the effect that all 'day 
a,nd night butterflies' are without exception positively photo- 
tropic. I am led to suspect, however, that some of the reactions 
noted by Axenfeld were the results of contact stimulus, for Hess 
('13 a, p. 651) has shown that Coccinella, which Axenfeld reports 
.as circling toward the blackened eye, is not negative to light. 
Axenfeld's experiments, therefore, need careful repetition before 
any final conclusions may be drawn from them. 

It seems quite certain, therefore, that what have appeared to 
be exceptions to the general occurrence of circus movements 
among phototropic arthropods are not really incompatible with 
this view. Taken as a whole, the investigations of these reac- 
tions demonstrate rather conclusively that, although they may 
be modified through experience or obscured by responses to other 
than photic stimuli, they are, nevertheless, to be considered as 
characteristic of phototropic arthropods. Photic orientation in 
this group of animals, therefore, cannot be accounted for by any 
theory which fails to offer a satisfactory explanation of circus 
movements. 



350 DWIGHT E. MINNICH 

III. APPARATUS AND METHODS 
1. Directive Light 

In the experiments of the present paper, both directive and 
non-directive hght were . employed. Those involving directive 
illumination were carried on in a circular area (fig. 1) 2.44 m. in 
diameter, which was laid out in black lines on the concrete floor 
of a dark room. Sixteen centimeters' above the center of this 
area, ka incandescent lamp was suspended. The lamp employed 
was a 100-watt, 115-volt, stereopticon, Edison mazda lamp. Of 
several bulbs used in the course of experimentation, only the last 
was determined photometrically, its candle-power being approxi- 
mately 80. These lamps when new are calculated to furnish 
100 c.p., but their efficiency decreases considerably with usage. 

In making tests in the directive light area, bees were started 
creeping at the outer circumference. The course of the animal 
as it traveled toward the light was then traced as accurately as 
possible on a record bearing a plan similar to that of the light 
area and drawn to scale. Such a record is shown in figure 1. 

£. Non-directive light 

a. Construction. The apparatus employed to furnish non- 
directive light consisted essentially of a white-walled, cylindrical 
chamber. This chamber was illuminated by an incandescent ~ 
lamp, the light of which was diffused through a thin, white screen, 
suspended a short distance below the lamp. Bees were admitted 
to the apparatus through a small, circular opening in the center 
of the floor, and the course of their creeping was then traced as 
accurately as possible on a record. The apparatus was espe- 
cially designed to afford a creeping animal a continuous photic 
stimulation of uniform intensity over the entire surface of the 
eye. A more detailed description is presented in the following,, 
paragraphs (see, figure 2). 

' Distances from lamps to creeping surfaces were measured from the center of 
the filament in all cases. 



PHOTIC BEACTIONS OF HONEY-BEE 



351 



The cylindrical chamber, which measured approximately 84 
cm. in height by 87 cm. in diameter, was constructed on a light 
wooden framework covered on the exterior with heavy, corru- 
gated cardboard. On the interior it was lined with a thickness 



C\ 



y 



Fig. 1 Plan of directive light area, showing two trails of a normal bee. Note 
the deflection of the courses in the non-directive region near the lamp and directly 
beneath it. 

of dead white, cotton cloth, backed by a layer of heavy white 
paper. On one side of the cylinder, and extending from its bot- 
tom edge, a rectangular opening 58 cm. high by 32 cm. wide was 
cut through the cardboard and paper layers. The white cloth 
lining only closed this opening, and it was here slit from top to 
bottom, the bottom edges being left free. The two flaps thus 



352 



DWIGHT E. MINNICH 



formed allowed free access to the interior of the cylinder In 
oneiof them a small opening (fig. 2, o), 3 by 4 cm., was cut for 
purposes of observation. 

The top of the cylinder was similar in construction to the side 
walls'except that the cardboard layer was omitted. Near oppo- 
site edges of the top, two circular openings, 8 cm. m diameter. 




Fig. 2 Diagrammatic section through non-directive light apparatus, c, 
transferring cage; e, entrance to light chamber; h, handle of slide opening and 
closing e; o, opening for observation; s, light screen; v, ventilators. 

were cut (fig. 2, v). These were covered with a thin, white gauze 
of coarse mesh, and served as ventilators, preventing any undue 
rise of temperature within the apparatus. The bottom of the 
cylinder was formed by a layer of heavy, dead white paper, which 
covered the table on which the cylinder stood. This paper was 
especially selected to afford a good creeping surface. On it was 
drawn a plan, similar to that shown in figure 3, by means of which 
the course of a creeping bee could be accurately followed. 



PHOTIC REACTIONS OF HONEY-BEE 



353 



The illumination of the apparatus resembled the semi-indirect 
illumination of a modern house, the light from an incandescent 
lamp being diffused through a circular screen (fig. 2, s), 22 cm. in 
diameter, of white bond paper. Two intensities of illumination 
were employed. The less intense was produced by a carbon 
filament lamp of approximately 2 c.p.,^ 66 cm. above the floor, 
and the more intense by the 80 c.p. mazda lamp previously 
described, 33 cm. above the floor. The intensity of illumination 
in each instance was measured at three different points on the 
floor of the cylinder. One determination was made at the cen- 
ter; a second at a point 3 cm. from the right side wall, and a third, 
at a point 3 cm. from the left side wall. The results of these 
measurements are given in table 1. Hereafter, in referring to the 

TABLE 1 



i. 


B 


c 

INTENSITT ON 


D 

INTENSITT ON 


i:^ 


F 


CANDLE-POWER 


INTEJTSITT ON 


FLOOR 3 CM. 


FLOOR 3 CM. 


AVERAGE OFC 


AVERAGE OF B 


OFLAUP 


FLOOR AT CENTER 


PKOM RIGHT SIDE 
■WALL 


FROM LEFT SIDE 
WALL 


AND D 


ANDE 


e.p. 


mc.^ 


mc. 


mc. 


mc. 


mc. 


2.36 


25.9 


17.93 


25.25 


21.59 


23.75 


79.45 


1051.5 


831.37 


894.45 


862.91 


957.21 



two intensities of illumination employed, the averages given in the 
table will be used in round numbers. The less intense will be 
designated as non-directive light of 24 mc. ; the more intense, as 
non-directive light of 957 mc. 

The transference of bees to and from the apparatus was effected 
by means of a small, cylindrical cage of wire screen, 5 cm. in 
length by 2 cm. in diameter (fig. 2, c). This cage, one end of 
which was open, exactly fitted into a circular opening cut through 
the table top to the center of the chamber floor. By means of a 



* The lamp used throughout experimentation was, unfortunately, broken 
before being determined photometrically. Its candle-power was certainly 
between 2 and 4. 

* Throughout the present paper, the abbreviation mc. will be used to designate 
meter candles. 



354 DWIGHT E. MINNICH 

slide operated by a handle (fig. 2, h), it was possible, after in- 
serting the cage, to open or close the light chamber at will. The 
difficulties involved in direct manipulation of bees were thus 
entirely avoided. An individual to be tested in non-directive 
light was merely allowed to creep into the cage, which was then 
inserted into the opening in the table top. The slide was then 
pushed aside and the bee allowed to creep up on to the floor of the 
apparatus. As soon as the bee had entered the light chamber, 
the slide was pushed back, closing the entrance and leaving the 
floor of the apparatus complete. 

The ideal apparatus for studying the effects of continuous pho- 
tic stimulation of a constant intensity would be one so constructed 
that all the ommatidia of a compound eye would receive equal 
illumination, irrespective of the direction of locomotion. Such 
an apparatus is virtually, a physical impossibility. However, 
the apparatus just described is perhaps somewhat of an approxi- 
mation to it, even if it does not afford an absolutely uniform light 
intensity over the floor of the light chamber. As table 1 shows, 
the illumination is more intense toward the center. Some fluc- 
tuation will, therefore, occur in the stimulation of the various 
ommatidia as the animal moves. However, in any position 
whatever on the floor of such a light chamber, all the ommatidia 
are receiving some stimulation. Moreover, the amount of stimu- 
lation received by those areas of the eye which are minimally 
affected does not differ vastly from that received by areas of 
maximal stimulation. 

b. Records. The method of recording behavior in non-directive 
Ught is illustrated in figures 3 and 4. The animal to be tested 
was transferred to the light chamber, and its course of creeping, 
observed through the 'peep hole' in the curtain, was traced as care- 
fully as possible on a record sheet. The record bore a plan simi- 
lar to that on the floor of the light chamber, drawn on a scale of 
1 to 6. The duration of each trial was ascertained by counting 
the rings of an electric bell, attached to an electric clock regulated 
to seconds. How long the trial should last was determined by 
an mterval previously decided upon or by the animal encountering 
the side wall of the chamber and creeping up. On completion of 



PHOTIC EEACTIONS OF- HONEY-BEE 355 

:a trial, the bee was removed, and the remaining data called for 
on each record were entered. The tracing was marked with 
arrows to indicate its direction. Observations on the physical 
condition of the animal and others of importance, which were 
made from time to time, were also noted on the record. All the 
records of a single animal were then filed away together, thus 
affording a permanent record for further reference. 

Since it was desired to make a quantitative study of circus 
movements, it was necessary to adopt some method whereby the 
amount of tiirning exhibited by an animal, in a given trial or 
group of trials, might be expressed as a single value. These 
values have been stated in terms of average number of degrees 
turned per centimeter of progress, and were obtained in the fol- 
lowing manner. The length of the trail was first measured with 
a map tracer. Several readings were taken until two were ob- 
tained with a difference of less than 0.3 cm. These were then 
averaged, and the result used in computations. Thus in figure 3, 
the length of the or'ginal tracing is 26.95 cm. Since, however, 
the records were on a scale of 1 to 6, and these in reprod!uction 
have been reduced one half, the length of the text figure tracing 
must be multiplied by (6 X 2 =) 12 in order to obtain the dis- 
tance actually traveled by the animal. 

The various turns or angular deflections of the trail were next 
estimated by reference to the radii of the plan. It is obvious 
that in traveling a curved course, the direction of locomotion at 
.any given instant is the tangent to the curve at that point. For 
example, in figure 3 the initial direction of locomotion is shown 
by the tangent at a. This direction is parallel to a radius. From 
a, the tangent to the curve or the direction of locomotion rotates 
-continuously to the left until the point b is reached. At b the 
tangent is parallel to a second radius, which makes with the radius 
■of initial parallelism an angle of | of 360° or 180°. (Each radius 
forms angles of 45° or | of 360° with its adjacent radii.) In 
■other words, in traveling from a to b the axis of the animal's 
t)ody has rotated 180° to. the left, or the animal has executed J 
■of a complete sinistral loop. Similarly, from b to c the coiu-se of 
the animal makes If dextral loops; from c to d, | of a sinistral 



356 



DWIGHT E. MINNICH 



loop, and finally from d to e, U dextral loops. The total amount 
of turning, or angular deflection, toward the right m this trail is, 
therefore, If + 1| or 2| X 360°, whUe that to the left is ^ + s 

or f X 360°. . J . ,, . 

Since the honey-bee is positively phototropic and m this case 
the left eye was blackened, the angular deflection toward the 
right or functional eye is designated as positive; that toward the 
left or covered eye, as negative. The algebraic sum of these 

Animal ftW >ymlU4iao. 
Experiment No. II 
Na of Animal 3 
Date 'y!;/^ 

Time) ■'=" " 
'™=1 30 sj 




Eye black 

Light I* 

No. dx. loops l3i;-n^=W- 

No. sn. loops K + >i= H 

Trail length, cm. 2 i.s """ 

Fig. 3 Record of bee no. 123 in non-directive light. 

angular deflections will give a result equivalent to the amount 
of continuous turning required to carry the animal from the start- 
ing point to the end of its course. Thus, in figure 3, the direction 
of locomotion at a makes with the direction at e an angle, of 2| 
X .360° - f X 360° or 2| X 360°. 

Knowing the distance traveled in centimeters and the amount 
of turning in degrees, the average degrees turned per centimeter 
is easily computed. Denoting this average deflection, as I shall 
call it, by D, we have for the trail in figure 3, 



PHOTIC REACTIONS OF HONEY-BEE 



357 



D 



2| X 360° 
26.95cm. x6 = +^-^l°/^"^- 



It is to be emphasized that the value + 5.01° /cm., does not sig- 
nify that the animal turned only toward the functional eye. It 
merely shows that the algebraic sum of all its deflections aver- 
ages 5.01°/cm. toward the functional eye. 



Animal fi^uui, rruULU|uva. 
Experiment No. 13 
Naof Am'ma] 5 
Date 'lii 




Eye black 

Light 157 

No. dx. loops a %" fc/i""-.^ 

Na sn. loops a^ h^ ^^-- 

Trail length, cm. a 11.3 i> -7.1 
I a- J XI 

11.25 V 1J ib 

Fig. 4 Two trails of bee no. 135 in non-directive light. 

A record is shown in figure 4 which represents two trials taken 
in rapid succession. This was necessitated by the animal's en- 
countering the side wall of the light chamber so quickly that the 
first trial was shorter than usual. The deflections in these trails 
are estimated as previously described. It will be noted, however, 
that in the trail marked a, the angular deflection between m 
and n does not amount to quite | of a sinistral loop, although it is 
so counted. In such instances the angle was always estimated 



THE JOURNAL OF EXPEHIMENTAL ZOdLOaY, VOL. 29, NO. 3 



358 DWIGHT E. MINNICH 

to the nearer | of a circumference, no attempt being made to 
discriminate differences of less than 45°. In this record it is 
desirable to combine both trails into a single computation. Pro- 
ceeding as before, 

(+1 + 1-1-1)360° _ 
^- (12.25 + 7.1 cm.) 6 " l-l" /cm. 

The negative sign of the average deflection here obviously indi- 
cates that the bee turned more toward the covered eye than 
toward the functional eye in these trials. 

In the course of experimentation, records of normal bees were 
also made in non-directive light. Since in such individuals neither 
eye was blackened, the positive sign was arbitrarily applied to the 
direction of greater angular deflection in each set of trials. Other- 
wise the computations for normal bees were performed in the 
same manner as those for bees with one eye blackened. 

These various examples will illustrate the method employed in 
all quantitative determinations. Upon the results thus obtained 
the chief conclusions of the present paper are based. 

IV. MATERIAL 

i. General care of animals 

The bees used in all quantitative experiments were thoroughly 
active workers taken from the flowers of a near-by garden, and 
were, for the most part, individuals from a single large hive situ- 
ated there. The animals were trapped by simply inverting a 
long glass tumbler over the flower, and then transferring them 
to a small screen fly-trap. In some experiments, however, which 
were performed too late in the fall to obtain bees in this way, 
animals were used from a single comb of workers confined in an 
observation hive. The exit of the hive was kept securely screened, 
for such a colony quickly disintegrates if its members are per- 
mitted to leave the hive freely. Bees kept in this way remained 
in reasonably good condition, for at least a month. 

Bees destined to undergo experimentation were first subjected 
to having their wings clipped, an operation easily executed when 



PHOTIC REACTIONS OF HONEY-BEE 359 

the animals were feeding. Each wingless individual was then 
confined in a small cylindrical cage of screen wire, the bottom of 
which was formed by a layer of tissue-paper over cotton to pre- 
vent injury in case of falling. In the same cage were also placed 
two friendly winged workers to counteract any possible effects 
of isolation. The cages of bees were kept in a darkened box when 
not directly under experimentation, since the influence of light 
often caused the animals to maintain a restless activity which 
appeared, in some cases, to shorten life considerably. In the 
dark, however, they usually remained more quiet. 

Each cage was supplied with water by a small wad of saturated 
cotton placed on its top. Small quantities of honey were also 
supplied on short wooden sticks stuck to the side of the cage. 
Early in the morning, at noon, and in the evening the cages 
were cleaned by removing excess honey, etc., and fresh honey 
and water were provided. Such operations were carried out at 
least a half-hour before any trials were made on the animals. 

The temperature of the laboratory in most of the experiments 
was kept above 20° to 21°C. This was found to be an important 
consideration, since at lower temperatures bees became torpid 
and inactive. In collecting the animals even, an attempt was 
made to take them on warm, sunny days which had, in general, 
been preceded by warm weather. It was found that bees brought 
in after a brief period of cold, wet weather were apt to be either 
unresponsive or extremely variable in their behavior. 

2. Blackening the eye 

Any technic for blackening the eye of a wingless bee requires, 
of course, the use of an anaesthetic. In the present experiments 
ether was used exclusively. Care was taken to administer it 
rather slowly and in minimal doses. When completely anaes- 
thetized, the bee was placed on one side, on a small cork pinning 
board. Here it was fastened down securely by the use of insect 
pins, with which the thorax, abdomen, and legs were securely 
braced against the cork. The blackening was then applied to the 
eye, the entire surface being covered with as thick a coat as pos- 



360 DWIGHT E. MINNICH 

sible. Two kinds of blackening material were used, viz., kmp- 
black in shellac and a dead black paint known commercially 
as 'Jap-a-lac' The latter proved the more satisfactory and was 
used throughout the majority of experiments. 

Although bees under ether often began to recover in five to 
ten minutes, they were not removed from the pinning board for 
twenty to twenty-five minutes, when the covering of the eye was 
well hardened. Recovery from anaesthesia was usually com- 
plete in an hour and often much less. As a rule, however, opera- 
tions were carried out in the evening, and the bees were not sub- 
jected to further experiment until the following day. Ample 
time was thus allowed for the animals to recover as much as 
possible from the effects of the operation. 

V. BEHAVIOR OF NORMAL BEES 
1 . Kinetic effect of light 

The remarkable sensitivity of the honey-bee to photic stimu- 
lation must have long been patent to students of its behavior. 
Bethe ('98, p. 83) says, "Das Licht ist bei diesen Tagthieren 
[bees, flies, etc.] der auslosende Reiz zum Fliegen; in einer dunklen 
Schachtel fliegt keine Biene auf , auch nicht, wenn man sie reizt. 
Das Licht gibt die ReguUrung beim Fluge ab." This observa- 
tion was repeatedly confirmed in the present experiments. When 
collecting bees from flowers, fifteen to twenty individuals were 
confined in a siagle cage, which was then placed in a closed box. 
Although at the height of activity when captured, a few minutes 
in the darkness of the box seldom failed to reduce these animals 
to a state of quiescence. If a little light was admitted to the box, 
however, by even partially removing the hd, there was a sudden 
resxunption of activity. 

Precisely the same behavior was exhibited by wingless bees. 
If confined in a dark box, they were, as a rule, reduced to com- 
parative inactivity. A brief exposure to light, however, was 
usually sufficient to excite vigorous locomotion, and continued 
exposure not infrequently resulted in the maintenance of an 
intense activity for extended intervals of time. 



PHOTIC EEACTIONS OP HONEY-BEE 361 

Individuals which had been subjected to operations of remov- 
ing the wings and blackening the eye frequently responded some- 
what more slowly to this photic activation than did normal 
bees. In the former, locomotion was preceded by a more or less 
prolonged sequence of cleaning operations. The proboscis was 
extended and stroked with the fore legs. The eyes, particularly 
the covered one, were the objects of repeated and vigorous scrap- 
ings, responses no doubt largely attributable to the irritation of 
th'e blackening material. The abdomen was meanwhile bent 
from side to side, while the middle or hind legs were rubbed to- 
gether, or the hind legs assiduously stroked the dorsum of the 
abdomen. These movements became more and more intense 
until at length they culminated in active creeping. 

Light, then, exerts a strong activating or kinetic influence 
upon the honey-bee, while darkness has the opposite effect. Es- 
sentially similar phenomena have been reported by Loeb ('90) 
for the plant louse. Carpenter ('05) for the pomace fly, and 
Turner ('12) for the mason wasp. Stockard ('08) has reported 
the case of Aplopus, the 'walking-stick,' which also falls into this 
category of behavior. In Aplopus, however, light inhibits ac- 
tivity, while darkness induces it. Hence the 'walking-stick' is 
nocturnal, whereas the plant louse, the pomace fly, the mason 
wasp, and the hive bee are diurnal. 

In diurnal animals this response is apparently due to the con- 
tinued action of light rather than a sudden change in it. Thus, 
while many bees respond almost, if not quite, at once to the 
presence of light, others may respond only after some minutes of 
exposure. According to Turner ('12, p. 360), the same is true 
of the mason wasp. 

2. Directive light 

Not only does light induce locomotion in the honey-bee, but 
directive light regulates the course of locomotion. Bees brought 
into the laboratory direct from their foraging activities out of 
doors seldom failed to exhibit a most striking phototropism. 
Such insects when liberated in the laboratory flew almost im- 
mediately to the nearest window, where they remained fluttering 



362 DWIGHT E. MINNICH 

against the glass. Or, if escaping in a darkened room, they not 
infrequently flew directly into the flame of the nearest gas jet. 

Observations of this sort were long ago reported by Lubbock 
('82, pp. 278, 279, 284). A few years later, Graber ('84) demon- 
strated the same thing experimentally by confining forty to sixty 
bees in a small box, one half of which was illuminated by direct 
sunhght, the other half being shaded, with the result that the 
majority of the bees soon collected in the illuminated end. More 
recently, Hess ('13 a, '13 b, '17) has repeated this and a variety 
of other experiments. As a result of these he has been able to 
show that in the presence of several sources of photic stimulation, 
which differ in color and intensity, bees always orient toward 
the one which to a totally color-blind person appears brightest. 
The positive phototropism of the honey-bee is thus demonstrable 
in a variety of ways. 

In the experiments just cited, winged bees were used exclu- 
sively. My own experiments, on the contrary, were confined en- 
tirely to workers from which the wings had been clipped. Such 
bees when creeping in the directive light area exhibited an orien- 
tation which was striking in three respects, viz., its rapidity, its 
precision, and its constancy. 

An individual to be tested was removed from the dark box and 
exposed to light for a few minutes until it was thoroughly active. 
It was then allowed to creep from its screen cage to a small, 
rectangular piece of black paper, and on this it was transferred to 
the edge of the directive light area. An effort was made to start 
the animal creeping at a right angle to the direction of the hght 
rays by turning the paper just before it crept off. The rapidity 
of orientation was so great, however, that the intervening centi- 
meter or so was frequently sufficient to allow the animal to reorient 
perfectly. Since the velocity at which bees creep averages 3 to 6 
cm. per second, orientation in these cases occurred in considera- 
bly less than one second. I have also tried leading a bee by 
moving the light, now in this direction, now in that, with varying 
degrees of curvature. Always the animal followed, orienting rap- 
idly to even slight movements of the lamp. 



PHOTIC EEACTIONS OF HONEY-BEE 



363 



The precision with which orientation was maintained was no 
less conspicuous. Once oriented, the animal generally moved 
in a nearly straight line toward the source of light. In figure 5 
are shown two records of each of six bees in the directive light 
area. Of a large niunber of animals tested in the course of ex- 
perimentation, considerably over 25 per cent maintained their 
orientation as precisely as did bee no. 66. The deviations of 




Fig. 5 Two trails of each of six normal bees in directive light. In this, as in 
subsequent figures of records in directive light, the clear circle represents the light 
source, and the straight lines from it, the direction of the rays. 

most of the animals would, moreover, easily fall within the lati- 
tude of that exhibited by bees nos. 66, 33, and 23. Results sim- 
ilar to those shown for animals nos. 110 and 21 were, on the con- 
trary, less frequently encountered, while trails such as those of 
bee no. 36 were seldom or never found among normal, healthy 
bees. 

The response to directive light is very constant in the bee. 
The oncoming of death itself seems often to intensify rather than 
to weaken this phase of its behavior. Bees occasionally escaped 



364 



DWIGHT E. MINNICH 



in the laboratory. Such individuals rarely survived the lack of 
food for more than a day or so. Yet it was not an m^requen 
occurrence to observe one of these starved animals, so weak that it 
was barely able to creep, slowly emerging from a hidden corner 
in a final struggle toward the light. _ 

Nevertheless, bees were discovered which m a few mstances 
failed to exhibit the usual positive reaction to directive hght. 
Such|cases, however, are not to be construed as a total absence 



? 




Fig. 6 Three successive records of a normal bee in directive light, showing a 
failure to orient in two cases. 

of phototropism, but rather its momentary suppression by other 
factors of behavior. This is well illustrated by the following 
example. Seven cages of bees were prepared from the stock in 
the observation hive, Oct. 30, at 2:45 p.m. When tested about 
an hour later in the directive light area, six of the seven animals 
exhibited the usual positive response. One animal, however, gave 
the records reproduced in figure 6. 

This bee when given its first trial at 4: 06 (fig. &, 1) did not ori- 
ent toward the light source. Instead it pursued a devious course 



PHOTIC REACTIONS OF HONEY-BEE 365 

looping now to the right, now to the left, and finally turning al- 
most directly away from the light. In a second trial at 4:14, it 
exhibited a somewhat similar response (fig. 6, 2). One minute 
later, the animal was subjected to still a third trial, being started 
on this occasion some 30 cm. nearer the light. This time it ori- 
ented and moved in a fairly direct course toward the source of 
illumination (fig. 6, 3). What the temporary, inhibiting factors 
were which produced these very atypical responses could not be 
ascertained. In all other respects this bee was quite indistin- 
guishable from the other individuals in the experiment. This 
example, however, shows that even the constant response of the 
bee to directive illumination is not free from abrupt and appar- 
ently inexplicable departures. 

3. Non-directive light 

The behavior of bees in non-directive light is no less charac- 
teristic than that in directive illumination. Since aU quantita- 
tive experiments on circus movements were conducted in non- 
directive light, an intimate acquaintance with the behavior of 
normal animals under the same conditions was necessary. Every 
bee was, therefore, subjected to several trials in non-directive 
light before having one eye blackened. 

It was a matter of continual observation that a bee creeping in 
the directive light area ceased to move in a straight course upon 
reaching the area near and immediately beneath the lamp. 
Here, where the illumination was essentially non-directive, the 
xinimal deflected from its former, precise path and began to loop 
in a constant or varying direction (fig. 1). In other words, the 
bee was trapped; for directly it crept away sufficiently for the light 
to become directive again, it was forced to turn back. Thus the 
Animal continued to creep round and round in a limited area, 
occasionally rearing on its hind legs in an abortive attempt at 
flight, or finally ceasing locomotion to begin cleaning operations. 

In the non-directive fight apparatus (fig. 2), the same tend- 
ency to loop was manifested, only on a much more extensive 
5cale. Here the bee seldom crept in a straight line for any great 



366 DWIGHT E. MINNICH 

distance. Each animal was subjected to two sets of trials, an 
hour or so apart. Usually a single trial only constituted a set. 
In case the bee quickly encountered the side wall of the light 
chamber, however, or exhibited unusual variabihty in its be- 
havior, additional trials were made. The aggregate duration of 
the trials of each set varied considerably, even in the same animal. 
Sometimes they were as short as thirty seconds; again, as long as 
two minutes. The average was in the neighborhood of thirty 
to sixty seconds. Preliminary to each trial, the bee was exposed 
to light until aroused to active creeping. The illumination used 
throughout in experimenting with normal bees was 957 mc.^ 

The average deflection to the right or to the left has been 
computed for each set of records thus obtained, and the results 
of these computations presented in table 2 (appendix), columns B 
and C. On the basis of these data, the fifty-two bees experi- 
mented upon may be classified into three groups : 

1. Bees whose average deflection in both sets of trials was over 
2°/cm. and in the same direction. 

2. Bees whose average deflection in both sets of trials was 
small. 

3. Bees whose average deflection in the two sets of trials varied 
widely, either in magnitude or direction, or in both. 

The flrst class is composed of animals which exhibited a more 
or less pronounced tendency to turn in a constant direction (right 
or left). These animals, 29 in number, comprised 56 per cent 
of the total 52 bees. Fourteen of these were chiefly right-handed 
in their turns; 15, left-handed. In 14 of the 29 bees, or 27 per 
cent of the total number, the average deflections exceeded 4°/cm. 
while in 6 individuals, or 12 per cent, it rose to over 8° /cm. Sim- 
ilar right and left-handed tendencies of locomotion in non-direct- 
ive Ught have been reported by Walter ('07) for planarians and 
by Patten ('14) for the blowfly larva. A typical example of this 
behavior in bees is illustrated in figure 7, bee no. 101. In its first 
trial (fig. 7, 101, a), this animal showed an average deflection of 
7.11°/cm. to the left, and in the second trial (fig. 7, 101, b), a sim- 
ilar deflection of 6. 10°/cm. Since these records were made nearly 
an hour apart the left-handed tendency was not the result of a 



PHOTIC REACTIONS OP HONEY-BEE 
lOi 



367 





36 




Left - BigU 



Left ^ Right 




Right 




Fig. 7 Kecords of normal bees in non-directive light. In this, as in subse- 
quent figures of records in non-directive light, a solid circle is used to indicate the 
center of the floor of the non-directive light apparatus, o, records of the first set 
of trials; 6, records of the second set of trials. Bee no. 101 deflected constantly 
toward the left. Bee no. 36 varied its deflection in the course of single trials. 



368 D WIGHT E. MINNICH 

brief, temporary condition, but was probably a more or less 
permanent feature of this animal's behavior. 

The second class of animals includes those whose average de- 
flections were small in both directions. The results obtained 
here are attributable to either of two causes : 

a. The bee varied its turning from right to left, so that on an 
average, one tendency nearly or quite balanced the other. 

b. The bee exhibited little or no tendency to turn either to the 
right or to the left. 

An example of the first type is seen in the records of bee no. 36, 
figure 7. In its first set of trials (a, 1, 2) this animal turned 
sometimes to the left, sometimes to the right, so that the result- 
ant average deflection was but 0.79°/cm. to the left. Similarly 
in the second set of trails (&, 1,2), the average deflection amounted 
to only 1.94°/cm. to the right. The second type of this class is 
illustrated by bee no. 134, figure 8. This animal showed no pro- 
nounced tendency to turn either to the right or left. The aver- 
age deflection for each set of records was, therefore, small, being 
only 1.527cm. to the left for the first set (a, 1, 2, 3) and 1.227cm. 
to the left for the second set (b, 1, 2, 3, 4). 

In the third class of bees are to be found those which, although 
they exhibited fairly uniform behavior in a single set of trials, 
varied widely in different sets. For example, bee no. 82, in its 
first record (fig. 8, 82, o) showed a pronounced deflection which 
averaged 5.81°/cm. to the left. In its second set of trials (fig. 
8, 82, b, 1, 2, 3, 4), on the contrary, it showed little tendency to 
turn, and the average deflection was but 0.65°/cm. to the left. 
An even more striking case of variation, however, was afforded 
by bee no. 63. In a single record of fifty-three seconds' duration 
(fig. 8, 63, a) this animal deflected, on the average, 5.58°/cm. to 
the left. Approximately two hours later, in a record of sixty 
seconds' duration (fig. 8, 63, b), the same animal exhibited an 
even greater average deflection in the opposite direction, viz., 
7.50°/cm. to the right. The range of variation presented by 
these two records is no less than 13.08°/cm. 

In a uniform, non-directive Ught field, therefore, many bees 
exhibit a fairly constant tendency to turn toward a given side 



PHOTIC REACTIONS OF HONEY-BEE 



369 



^r= 



134 








63 





Fig. 8 Records of normal bees in non-directive light, o, records of the first 
set of trials; 6, records of the second set of trials. Bee no. 134 exhibited little 
tendency to deflect in either direction. Bees nos. 82 and 63 varied widely in their 
average deflections in the two sets of trials. 



370 DWIGHT E. MINNICH 

others display little or no such tendency, while still others vary 
widely in their deflections from time to time. Since the animal 
moves in a uniform environment, the conspicuous asymmetry 
of response so frequently noted must be attributed to internal 
factors. Such factors are, for the most part, probably quite in- 
dependent of hght. A more detailed discussion of these will be 
presented in a subsequent section of this paper. 

4. Total darkness 

If internal factors are responsible for the asymmetric responses 
of bees in non-directive illumination, a similar behavior should 
be exhibited in the total absence of photic stimulation. Such 
was indeed the case. Animals creeping on smoked paper, in 
total darkness, showed the same conspicuous tendencies to loop 
and turn as did animals in non-directive light (fig. 16). The 
data here referred to were taken in connection with experiments 
conducted for a different purpose. They are, therefore, not 
sufficiently extensive to establish more than a similarity to the 
behavior exhibited in non-directive light. 

Responses essentially like those of bees in total darkness have 
also been described by Pouchet ('72) for the larvae of Lucilia 
caesar, Davenport ('97) for the amoeba, and Frandsen ('01) for 
the garden slug Limax. Frandsen' s observations in particular 
bear a striking resemblance to those which I have just described 
for the honey-bee in non-directive light. Thus he found that 
while most of his animals looped in a fairly constant fashion to 
the right or left, a few were extremely variable, while still a few 
others moved in rather straight courses. The responses of creep- 
ing bees in the total absence of photic stimulation are, therefore, 
very similar to those observed for other animals under the same 
conditions. 

6. Summary 

In the preceding pages certain responses of normal bees have 
been described in considerable detail, but only as a prerequisite 
to an adequate understanding of the behavior of the animals 



PHOTIC REACTIONS OF HONEY-BEE 371 

when one eye is blackened. The features of behavior which are 
important in this connection may be summarized as follows : 

1. In the honey-bee, light tends to induce activity; darkness, 
to inhibit it. This response is dependent upon the continuous 
action of photic stimulation. 

2. Isolated worker bees in an active condition exhibit strong 
positive photptropism when flying or creeping. Temporary sup- 
pressions of this response may occur, however. 

3. Normal bees when creeping in non-directive light usually 
exhibit pronounced asymmetrical responses of constant or vari- 
able index. Since essentially the same responses occur in total 
darkness they are not fundamentally dependent upon photic 
stimulation. They are probably, therefore, conditioned largely 
by internal factors. 

VI. BEHAVIOR OF BEES WITH ONE EYE BLACKENED 

1. Directive light 

The previous investigations of circus movements have pointed 
unmistakably to the generality of these responses among photo- 
tropic arthropods. Positive animals with one eye covered tend 
to circle toward the functional eye; negative animals, under the 
same conditions, tend to circle away from the functional eye. 
The honey-bee exhibits a striking positive phototropism. When 
one eye is blackened, therefore, we should expect the bee to circle 
toward the remaining functional eye. Such is indeed the case, 
as Axenfeld ('99, p. 374) has previously shown. 

In my own experiments, bees thus operated upon were no 
longer able to creep in a straight course toward a source of il- 
lumination. Instead, their progress thither was marked by re- 
peated loops. If the right eye was blackened, the bee looped to 
the left; if the left eye was blackened, it looped to the right. 
Moreover, it was possible by blackening one eye, then removing 
the black and blacking the other eye, to cause a single individual 
to perform circus movements first in one direction, then in the 
■opposite direction. 



372 DWIGHT E. MINNICH 

The above experiment was carried out on five bees. In gen- 
eral, all of these animals looped more or less markedly toward the 
functional eye as they crept toward the light source. This tend- 
ency, moreover, was not confined to the period inamediately 
subsequent to the operation of blackening the eye, as the experi- 
ment clearly demonstrates. The first records of these bees with 
their left eyes blackened were taken in the evening between 6 
and 7 p.m. No further tests were made until the following day 
at 11:30 A.M. Yet the behavior at the end of this seventeen- 
hour period was practically the same as it had been before. One 
bee, it is true, showed considerable improvement. In the other 
four animals, however, the two sets of records were indistinguish- 
able. In the absence of experience, therefore, the performance 
of circus movements remains a permanent feature of behavior. 

Of the five bees tested, the most pronounced and uniform exhi- 
bition of circus movements was displayed by bee no. 5. Its' 
records are almost diagrammatic in their close approximation to 
the theoretical expectation. Records of this animal are repro- 
duced in figure 9. 

Not all of these animals, however, yielded such striking results. 
Some individuals were found which manifested little or no tend- 
ency to deviate toward the functional eye, except in the area 
immediately beneath the lamp, where the illumination was es- 
sentially non-directive. Thus, bee no. 4, with its right eye black- 
ened, circled toward the left in the usual manner. But a few 
hours later, when the black had been removed from the right 
eye and the left eye painted over, it exhibited little or no tend- 
ency to circle toward the right (fig. 10, B). The explanation 
at once suggests itself, that in such cases the eye was imperfectly 
covered, and hence not absolutely free from stimulation. This 
may be correct. As will be shown later, however, there are also 
a variety of other circumstances which might account for such 
behavior. 

The tendency to circle toward the blackened eye was not fre- 
quently encountered in the reactions of bees to directive light. 
No instance of it occurred in the experiment described above, al- 
though it was occasionally met with in other experiments. A 



PHOTIC REACTIONS OF HONEY-BEE 



373 




Fig. 9 Consecutive records of a bee in directive light, showing the effect of 
blackening first one eye, then the other. 



THE JOUBNAL OP EXPERIMENTAL ZOOLOGY, VOL. 29, NO. 3 



374 



DWIGHT E. MINNICH 



single record of this kind is shown in figure 10, A. This was ob- 
tained from an animal which subsequently became wholly unre- 
active. Its aberrant tendencies may, therefore, have been due 
to an abnormal condition. In any case it is significant that, al- 
though the bee looped toward the covered eye, yet it progressed 
toward the light source. Consequently, this was not a case of 
reversal of phototropism. 

Instances somewhat similar to the one last mentioned have 
been described by DoUey ('16, p. 373) for the butterfly Vanessa. 

O 




Fig. 10 A. Record of a bee in directive light, showing loops toward the 
blackened eye. B. Two records of a bee in directive light which showed no 
deflection, although the left eye was blackened. 

Although positive to light, this insect with one eye blackened 
occasionally turned toward the covered eye instead of toward the 
functional eye. Possibly results of this sort are to be attributed 
to the effect of contact stimulus afforded by the covering of the 
eye, as indicated by DoUey ('16, pp. 394-399). This will be dis- 
cussed more fully in a subsequent portion of the paper. 



2. Non-directive light 

a. Amount of turning. In non-directive light, bees with one eye 
blackened tended, in general, to turn more or less pronouncedly 
toward the functional eye. As was to be expected, the course 



PHOTIC REACTIONS OP HONEY-BEE 375 

taken by the animals under these conditions assumed no specific 
direction. They either continued to circle in a fairly limited 
area or proceeded in a looping fashion in any direction whatever. 
The variability of this response, moreover, was much greater 
than in the case of the response to directive light. Thus, a num- 
ber of animals circled almost continuously toward the covered 
eye in non-directive light, while still others varied, circling some- 
times toward the covered eye, sometimes toward the functional 
eye. This was doubtless true for much the same reasons that 
normal bees also exhibited a greater variability of response in 
non-directive light. 

Circus movements attendant upon the elimination of one pho- 
toreceptor undoubtedly represent the orienting process of an 
asymmetric animal. The specific photic stimulus, therefore, 
which produces these reactions must be identical with that which 
effects orientation in the normal animal. Whatever the nature 
of this stimulus be, moreover, it is afforded by both directive 
and non-directive light, since circus movements occur in either 
situation. What is the nature of this orienting stimulus? Per- 
haps the best method of demonstrating the dependence of a par- 
ticular response upon a certain stimulus is to show that the in- 
tensity of the response varies with the intensity of the stimulus in 
question. It seemed possible to attack this problem, therefore, 
through a study of the relationship existent between the amount 
of turning displayed by an animal with one eye blackened and 
the intensity of the illumination to which it was subjected. 

Non-directive illumination was chosen in preference to direc- 
tive illumination because of the simpler experimental conditions 
which the former affords. In directive light, every movement 
of the entire animal is accompanied by more or less complicated 
changes not only in the intensity of the stimulation received, but 
also in the area of the eye stimulated. As an animal with one 
eye covered moves toward a light source, the stimulation of the 
functional eye steadily increases. As it loops toward this eye, 
however, this steadily increasing stimulus is subjected to rapid 
and transitory fluctuations. When the animal begins to loop, 
the functional eye is first turned away from the light, resulting 



376 DWIGHT E. MINNICH 

in a rapid decrease of photic stimulation. As the loop is com- 
pleted, the photoreceptor in turn experiences an increase in 
stimulation. In non-directive illumination such as was employed 
in the present experiments, however, these complications are 
largely avoided. Photic stimulation here is maintained at a 
fairly uniform and constant intensity over the entire surface of 
the compound eye. 

Two slightly different types of experiment were performed. 
The procedure in the first type was as follows. Bees were col- 
lected from flowers in the morning between 8 and 10 o'clock, 
brought into the laboratory and prepared for experimentation. 
One and two hours later, respectively, they wer6 given single 
trials in the directive light area. On a basis of these records, 
individuals of abnormal tendencies were discarded, and those evinc- 
ing the greatest accuracy of orientation were selected. 

An hour or so later, the selected bees were tested in non- 
directive light of 957 me. Two sets of records, about one hour 
apart, were made of each animal. Each set was composed of 
one to several records, the aggregate duration of which, in gen- 
eral,' was between thirty and sixty seconds. An examination of 
the records showed clearly whether the individual was normally 
right-handed, left-handed, or variable in its deflection in non- 
directive light. These results determined which eye should be 
blackened. If, for example, a bee normally circled to the right, 
the right eye was covered. Whatever influence was exerted by 
photic stimulation, therefore, would tend to force the animal 
toward the left. In this manner, responses which might other- 
wise have been mistakenly attributed to photic stimulation were 
to some extent eliminated. 

The operations of blackening the eye were carried out in the 
late afternoon of the first day of experimentation, in accordance 
with the technic previously described. On the following morn- 
ing, before resuming experimentation, it was not infrequently 
necessary to discard a few additional animals either because of 
extreme weakness or occasionally death as a result of the operation. 

The majority of bees usually appeared quite normal, however, 
and were subjected to several series of trials in non-directive 



PHOTIC EEACTIONS OF HONEY-BEE 377 

light. Throughout a single series of consecutive trials, or, as I 
shall call it, a determination, one intensity of light only was 
employed. But in the total number of determinations the more 
intense illumination of 957 mc. and the less intense of 24 mc. were 
used an equal number of times. The animal to be tested was first 
removed from the dark box and exposed from half a minute to 
several minutes in the intensity of light in which it was to be 
tried. This was usually sufficient to activate the animal thor- 
oughly, and several records were then made in the nOn-directive 
hght chamber. In case the bee failed to respond to photic acti- 
vation, recourse was had to mechanical stimulation. The cage 
was tapped or even shaken fairly vigorously until locomotion 
was induced. This procedure seldom failed to elicit activity. 
When it did fail, it was usually necessary to discard the animal 
altogether. 

The number and duration of the records comprising a single 
series or determination varied widely even in the same animal. 
If the bee quickly encountered the side wall of the light chamber, 
records were short, and a number had to be taken. If, on the 
contrary, the animal kept well toward the center of the floor of 
the apparatus, one or two records were quite sufficient. In cases 
of great variability of response or unusual departures from the 
general, expected behavior, additional trials were made, on the 
assumption that a greater number would mpre accurately ex- 
press the average tendency of the animal. Single trials seldom 
exceeded thirty seconds, and were often much shorter. Occa- 
sionally, however, records of forty-five seconds, sixty seconds, 
or even slightly greater durations were taken. The aggregate 
duration of the trials comprising a single determination, for one 
intensity of light, was usually in the neighborhood of thirty or 
sixty or ninety seconds. The adoption of any more uniform 
period for aU animals, at all times, was quite impossible. 

Upon completion of a series of trials in one intensity of Ught, 
the bee was returned to the dark box. Here it was allowed to 
remain for a period of about fifteen minutes to one hour. In the 
earher experiments the longer period was practiced; in subsequent 
experiments, the shorter. After this period in the dark, the ani- 



378 



D WIGHT E. MINNICH 



mal was subjected to a second set of trials of the same aggregate 
duration as the first, but in the other of the two light intensities. 
The order in which the two intensities of illumination were em- 
ployed was varied from time to time. Sometimes the first de- 
termination was made in the more intense Ught; the second, in the 
less intense. Sometimes the reverse order was observed. 

A single series of records in one intensity of non-directive light 
together with the corresponding series in the other intensity con- 
stitute what I shall term a pair of determinations. The protocol 
of such a pair of determinations on bee no. 42 is given in table 3. 
JFour or five pairs of determinations were usually made on each in- 
dividual of an experiment in the course of a day, beginning 



TABLE 3 



DETERMINATION FOB NON-DIKECTITB LIGHT 
OF 24 MC. 


DETERMINATION FOR NON-DIRECTIVE LIGHT 
OF 957 MC. 


Number of 
record 


Hour of record 


Duration of 
record 


Number of 
record 


Hour of record 


Duration of 
record 


4 
5 
6 


1 :47 p.m. 
l:47Jp.m. 
1 :48 p.m. 


seconds 
30 
30 
■30 


1 
2 

3 


1:32 p.m. 

l:32Jp.m. 

l:33ip.m. 


seconds 
31 
30 
30 


Totals 


90 






91 







between 8 and 9 o'clock in the morning and concluding between 4 
and 5 in the afternoon. The bees often seemed to become slug- 
gish in the late afternoon. Whether this was due to fatigue or a 
natural rhythm of activity from day to night, I am unable to say. 
This phenomenon, however, led me to abandon any attempt to 
continue experimentation much after 5 o'clock. 

On the third and concluding day of the experiment, the scheme 
of the second day was again carried out as far as possible. Bees 
usually survived the first two days of experimentation, and in 
case they did not, the data on them were discarded. A number 
of individuals, however, failed to survive in fit condition for the 
trials of the third day, and still others had to be discarded in the 
course of the day, although in both cases the results were counted. 



PHOTIC REACTIONS OP HONEY-BEE 



379 



Some of the more vigorous animals survived not only a third day 
of experimentation, but lived on for three or four days, and in a 
few instances even longer. Although no further trials were made 
with such bees, they were kept and, as far as possible, records of 
their subsequent longevity taken. 

Having described the first type of non-directive light experi- 
ment in considerable detail, the second type may be described 
very briefly. It differed from the first only in the method of 
making pairs of determinations. In this case, the two determi- 
nations of a pair were made during the same period of time. 



TABLE 4 



DETERMINATION FOR NON-DIRECTIVE LIGHT 
OP 24 MO. 


DETERMINATION FOR NON-DIBBCTIVE LIGHT 
OF 957 MO. 


Number of 
record 


Hour of record 


Duration of 
record 


Number of 
record 


Hour of record 


Duration of 
record 


2 

4 
6 

7 


1 :43 p.m. 

1:51 p.m. 
1 :53 p.m. 

1 :59 p.m. 


seconds 
11 

23 
40 

30 


1 
3 

6 


1 :41 p.m. 
1:48 p.m. 

1 :56 p.m. 


seconds 

30 

44 

30 


Totals 


104 






104 







instead of an appreciable interval apart. The bee was first tested 
in one intensity of light, then within a minute or so in the other 
intensity, then again in the first, and so on until a series of one to 
five records had been completed for each intensity. Care was 
exercised, however, even with this rapid alternation of intensi- 
ties, always to expose the animal for thirty to sixty seconds in a 
given intensity before subjecting it to a trial in the same. The 
following protocol from bee no. 83 (table 4) will illustrate this 
method of making determinations. 

In both types of experiment, there were obtained for each bee 
a number of pairs of determinations, usually four to ten, depend- 
ing upon the longevity of the individual. The records of each 



380 DWIGHT E. MINNICH 

determination have been computed collectively in the manner 
already described. Single values have thus been derived which 
express the average deflection, or tendency to turn, exhibited by 
the animal in each determination. When the turning was chiefly 
toward the blackened eye, the sign of these values is negative; 
when chiefly toward the functional eye, it is positive. If, now, 
the value of each determination in 24 mc. light be subtracted 
from the corresponding one in 957 mc. Hght, differences will be 
obtained which should answer conclusively the question of rela- 
tionship between the amount of turning and the intensity of 
photic stimulation. 

The differences obtained in the manner just described I shall 
designate as d. A given value of d may be negative or positive. 
If it be negative, it signifies one of the two following possibilities : 

1. The bee turned more toward the blackened eye in an illumina- 
tion of 957 mc. than it did in one of 24 mc. 

For example, in the second pair of determinations on bee no. 
32 (table 2), 

957 mc. 24 mc. 

-13.287cm. - (-9.227cm.) = -4.067cm. 

2. The bee turned less toward the functional eye in an illumi- 
nation of 957 mc. than it did in one of 24 mc. 

For example in the second pair of determinations on bee no. 23, 

957 mc. 24 mc. 

+6.447cm. - (+8.927cm.) = -2.48°/cm. 

If, however, the value of d be positive, it signifies one of the 
two following possibilities : 

1. The bee turned less toward the blackened eye in an illumina- 
tion of 957 mc. than it did in one of 24- mc. 

For example, in the first pair of determinations on bee no. 31, 
957 mc. 24 mc. 

-3.877cm. - (-7.147cm.) = +3.277cm. 

2. The bee turned more toward the functional eye in an illumi- 
nation of 957 mc. than in one of 24- mc. 



PHOTIC REACTIONS OF HONEY-BEE 381 

For example, in the first pair of determinations on bee no. 21, 

957 mc. 24 mc. 

+29.417cm. - ( + 15.847cm.) = + 13.577cm. 

If the great majority of d values are of the first category, viz., 
negative, we may conclude that the animal experiences a greater 
impulse to turn toward the functional eye in an illumination of 
24 mc. than it does in one of 957 mc. If equal numbers of nega- 
tive and positive values occur, there is no relation between the 
intensities of photic stimulation employed and the amount of 
turning. If, however, d is generally positive, we may conclude 
that the tendency to turn toward the functional eye increases 
if the intensity of photic stimulation is sufficiently increased. 

Experimentation soon demonstrated that the only satisfactory 
solution of the problem was to be had through a statistical treat- 
ment of large numbers of data. Even the more constant animals 
often varied widely from one pair of determinations to another 
without any apparent external cause. Therefore, a large num- 
ber of bees were experimented upon and each individual was sub- 
jected to many tests, the averages of which were relied upon to 
indicate the general trend of behavior. In table 2 (appendix) are 
presented the results obtained from a careful measurement and 
computation of over two thousand records taken on fifty-two 
bees. On some individuals as few as sixteen records were taken; 
on others as many as seventy-four. This difference was due in 
part to varying longevity of individuals and in part to the fact 
that more favorable animals were frequently experimented with 
longer than less favorable ones. The determinations of approxi- 
mately the first half of the animals were made on the plan of the- 
first type of experiment, while the remainder were carried out 
according to the scheme used in the second type. 

From the figures presented in columns F and G of table 2, 
it is evident at once that there is a marked preponderance of 
the positive d values over tl^e negative. The ratio of the two is 
strikingly shown in the frequency polygon (fig. 11) Since the 
number of d values varied considerably with the individual, due 



382 



DWIGHT E. MINNICH 



to the causes noted above, I have included m the polygon only 
the first four values for each bee, thus giving equal weight to 
every animal. Of the total two hundred and seven" values rep- 
resented in the polygon, 81.16 per cent are positive, whereas- 
only 18.84 per cent are negative, a ratio of over 4 to 1. 



18.84% 



42 



E3 n 




,81.16% 



26 26 



TTT 



-16— 14 —12 -10 -8 -6 -4 -2 2 4 6 8 10 12 14 16 18 20 22 24 2S 

Degrees per cm. 

Fig. 11 Frequency polygon x)f the first four d values of fifty-two bees. The 
negative values are represented by the shaded areas ; the positive values, by the 
clear areas. 



' In the case of one bee it was possible to include only three values for d, 
because of a missing record. See Table 2. (Appendix), bee no. 45. 



PHOTIC BEACTIONS OF HONEY-BEE 383 

The objection might be raised that although the majority of 
values of d are positive, a number of them are too small to be of 
any significance. It is true that differences of the order of l°/cm. 
or less might easily be attributed to slight errors in tracing the 
course of a bee. Errors in recording, however, are as likely to 
occur in one direction as the other. Such is not the case with 
these small values. The class of d values betwen and — 2°/cm. 
contains but fifteen, while the class of to +2°/cm. numbers 
twenty-nine — nearly twice as many. 

Moreover, the mode of the curve, -t-2°/cm. to -[-4°/cm., lies 
well beyond these small values. Differences of this magnitude 
are readily detected in the records of bees which circled constantly 
toward the functional eye, as the pair of determinations in figure 
12 demonstrate. Each record shown in the figure was of exactly 
thirty seconds' duration. The first two were taken three min- 
utes apart in 24 mc. illumination, while the third and fourth 
were taken about twenty minutes later in 957 mc. illumination, 
one minute apart. The value of d in this case is -|-2.98°/cm. — 
about the average modal value. 

In bees exhibiting considerable variation in their deflections, 
however, d values, or of the modal class of even greater magni- 
tude, are not so easily recognized without the accompanying fig- 
vires. To illustrate this, I have selected a pair of determinations 
(fig. 13) approximating the mean value of the frequency polygon, 
which is +4.35°/cm. As attested by the data given in connec- 
tion with the figure, this animal was extremely variable in its 
direction of turning. All four records were taken in the brief 
period of eight minutes, nos. 1 and 2 being of twenty-eight sec- 
onds' duration each; nos. 3 and 4, of thirty seconds. The value 
of d is +4.09°/cm. — a fact which does not become apparent until 
the records are submitted to a careful scrutiny. 

The data presented in table 2 and figure 11 show clearly that 
bees with one eye blackened tend to turn more toward the func- 
tional eye in a non-directive illumination of 957 mc. than they 
do in one of 24 mc. The validity of this conclusion is confirmed 
by still another line of evidence. A certain number of animals 
were found to exhibit a very constant tendency to turn toward 



384 DWIGHT E. MINNICH 

the functional eye, which was always much more pronounced in 
the intense than in the weak illumination. In other words, these 
individuals always yielded positive values of d of rather high mag- 
nitude. Bees nos. 73, 83, 95, 105, and to a lesser extent numer- 
ous others afforded striking examples of such behavior. v_These 

24 mc. 





957 





9B7 mc. Light 




+Degrees 
turned 


—Degrees 
turned 


1440 





1485 






Fig. 12 A pair of determinations of bee no. 42, left eye black, non-directive 
light.^The records are numbered in the order in which they were taken. 

£4 mc. Light 

Number +Degrees -Degrees Number 

record ^""""^^ ^"^^^ record 

1 900 3 

2 945 4 
Average deflection, +9.49° /cm. Average deflection, +12.47° /cm. 

d = +2. 98° /cm. 

animals were all thoroughly vigorous individuals, surviving not 
only the three days of experimentation, but living on for at least 
two days thereafter. Two of these bees, in fact, survived no less 
than four days after the conclusion of the experiment. 

In figures 14 and 15 are shown pairs of determinations from 
two of these animals. The eight records of bee no. 73 (fig. 14) 
were taken in the course of 28 J minutes, while the six records of 



PHOTIC KEACTIONS OF HONEY-BEE 



385 



24 





957 



mc. 





I 



Fig. 13 A pair of determinations of bee no. 123, left eye black, non-directive 
light. The records are numbered in the order in which they were taken. 



Number 

of 
record 

2 
4 



H mc. Light 

H-Degrees 
turned 



495 
270 



Average deflection. 



— Degrees 
turned 

1170 
460 
-3.53° /cm. 
d = 



+4.09= 



Number 

of 
record 


B57 mc. Light 

-(-Degrees . 
turned 


—Degrees 
turned 


1 


630 





3 


225 


720 


Average deflection, +0.56° /cm. 


/cm. 







386 



DWIGHT E. MINNICH 



24 mc. 






957 




^ %, 



V 





Fig. 14 A pair of determinations of bee no. 73, left eye black, non-directive 
light. The records are numbered in the order in which they were taken. 



^it mc. Light 

+Degree8 

turned 

360 

45 

2115 

2070 



Number 

of 
record 

1 

3 

5 

7 
Average deflection, +6.07 



-Degrees 
turned 



Number 

of 
record 

2 
4 



90 




225 
7cm. Average deflection, +13.82° /cm. 

d = +7.75° /cm. 



957 mc. Light 




+Degrees 
turned 


—Degrees 
turned 


1485 





990 





3510 





4005 






PHOTIC EEACTIONS OP HONEY-BEE 



387 



bee no.. 105 (fig. 16) required only fifteen minutes. In bothfigures, 
each record of the top row is of exactly the same duration as the 
corresponding one of the lower row, except records 1 and 2 of 
bee no. 73, which differ by one second. It would be difiicult to 

24 mc. 






957 




^yj 





\ 



Fig. 15 A pair of determinations of bee no. 105, right eye black, non-directive 
light. The records are numbered in the order in which they were taken. 



Number 

of 
record 


H mc. Light 

H-Degrees 
turned 


— Degrees 
turned 


1 


1260 


45 


3 


855 





6 


1305 


90 



9B7 mc. Light 



Number 

of 
record 

2 

4 

6 

Average deflection, -|-6.74°/cm. Average deflection, -1-14.83° /cin 

' d = -1-8.09° /cm. 



+Degrees 
turned 

1935 
2430 
2520 



—Degrees 
turned 







imagine more conclusive results than those afforded by these two 
bees. 

It might be supposed that animals would be found which would 
exhibit the opposite of the condition just described. Such, how- 
ever, was not the case. I failed to find any individuals which 
continually circled more toward the functional eye in an illumi- 



388 DWIGHT E. MINNICH 

cation of 24 mc. than they did in one of 957 mc. Bees presenting 
a number of negative d values, such as nos. 22, 25, 34, 41, 43, 55, 
56, 62, 66, 85, 126, and 135, with one exception, showed an equal 
or 'greater number of positive values. The exception noted was 
bee no. 56. Three of the four pairs of determinations obtained 
on this animal not only yielded negative differences, but differ- 
ences of large magnitude as well. Bee no. 56, like a number of 
other individuals presenting a considerable number of nega,tive 
d values, varied considerably in its behavior and turned chiefly 
toward the blackened eye. How far the disturbing factors thus 
evidenced account for the results is not absolutely certain, since 
a number of bees of apparently similar tendencies yielded posi- 
tive values of d. Certainly, however, there are a number of 
factors, particularly in the type of experiment under considera- 
tion, which do interfere with the effect of photic stimulation. 
Some of these serve to intensify the response, while others tend to 
counteract or even completely annul it. Without attempting to 
minimize the significance of these negative data in the least, I 
believe some of them, probably all of them, find their explana- 
tion in such factors. If this be correct, the negative results ob- 
tained lie well within the range of variation which might be- 
expected in experimental work of this sort. A more extended 
discussion of the factors responsible for variability of behavior in 
the present experiments is presented in the next section of this- 
paper. 

The evidence in general, therefore, seems to warrant the con- 
clusion that bees with one eye blackened tend to turn more toward 
the functional eye in an illumination of 957 mc. than in one of 
24 mc. This tendency may result in the animal's actually turn- 
ing more toward the functional eye, or in its turning less toward 
the covered eye, depending upon the idiosyncrasies of the indi- 
vidual. In either case, however, with increased photic stimula- 
tion, there is an increased tendency toward the functional eye. 
The nature of the stimulus afforded by the apparatus employed 
was continuous and of almost uniform intensity, and since the 
circus movements of the honey-bee vary with the intensity of 
such stimulation, they must be dependent upon it. These con- 



PHOTIC EEACTIONS OF HONEY-BEE 389 

elusions are the exact antitheses of those reached by DoUey ('16) 
in his work on Vanessa. He says (p. 417): "Vanessaswith one 
eye blackened do not move in smaller circles in strong light than 
they do in weak light, unless it is extremely low. On the con- 
trary, the evidence seems to indicate that the stronger the light 
is the larger the circles are. These results also are not in har- 
mony with those demanded by the 'continuous action theory.' " 
I shall return later to a more complete consideration of the theo- 
retical significance of the results afforded by the honey-bee. 

&. Rate of locomotion. Although bees with one eye blackened 
tend to turn more toward the functional eye in a non-directive 
light of 957 mc. than they do in one of 24 mc, there is no differ- 
ence in the rate of locomotion in the two intensities. In table 5 
are given the average velocities of thirty-four bees for each of 
the two light intensities employed. These figures show a con- 
siderable range of individual variation, from as low as 3.49 cm. 
per second to as high as 6.77 cm. per second. There is, however, 
no consistent difference which might be attributed to the effect of 
light. Eighteen of the animals showed a greater velocity in 957 
mc. illumination; sixteen, in 24 mc. illimiination. Unilateral 
photic stimulation of the intensities employed is, therefore, 
without effect upon the rate of locomotion. 

S. Summary 

1. Bees with one eye blackened usually loop toward the func- 
tional eye "as they creep toward a source of light. Some indi- 
viduals are encountered however, which display little tendency to 
loop, and occasionally an animal will be found which loops toward 
the covered eye. In the absence of experience, the tendency to 
loop toward the functional eye remains a permanent feature of 
behavior. 

2. In non-directive light, bees with one eye blackened gener- 
ally circle toward the functional eye, although a number are 
found which circle more or less toward the covered eye. 

3. In a uniform non-directive illumination of 957 mc, the 
tendency to turn toward the functional eye is greater than it is 
in a similar illumination of 24 mc. 

THE JOUBNAI, OF EXFEBIMEHTAI. ZOOLOGT, VOL. 29, NO. 3 



390 



DWIGHT E. MINNICH 



4. Since the amount of turning varies directly with the intensity 
of continuous photic stimulation, the turning is produced by this 
stimulus. 

5. Unilateral photic stimulation of the intensities employed 
has no effect upon the rate of locomotion. 



TABLE 5 



A 


B 


c 


D 


NUMBES OF BEE 


VELOCITY CM. PER SEC. 
24 MC. LIGHT 


VELOCITY CM, PER SEC. 
957 MC. LIGHT 


0— B 


21 


6.10 


6.22 


+0.12 


22 


5.10 


5.12 


+0.02 


23 


5.02 


5.03 


+0.01 


24 


4.95 


5.18 


+0.23 


25 


4.67 


4.53 


-0.14 


31 


3.77 


4.23 


+0.46 


32 


4.20 


4.74 


+0.54 


33 


5.27 


5.19 


-0.08 


34 


4.78 


4.99 


+0.21 


36 


3.49 


3.63 


+0.14 


41 


4.45 


4.29 


-0.16 


42 


4.76 


4.30 


-0.46 


43 


5.59 


5.76 


+0.17 


44 


4.94 


4.90 


-0.04 


45 


4.36 


4.99 


+0.63 


51 


4.51 


4.40 


-0.11 


52 


5.09 


5.08 


-0.01 


53 


6.77 


6.53 


-0.24 


. 54 


5.53 


5.17 


-0.36 


55 


6.09 


5.21 


-0.88 


56 


5.32 


5.53 


+0.21 


62 


4.82 


4.59 


-0.23 


63 


5:80 


5.72 


-0.08 


66 


5.10 


5.15 


+0.05 


68 


5.14 


5.34 


+0.20 


72 


4.69 


4.87 


+0.18 


73 


4.97 


5.44 


+0.47 


77 


4.26 


3,99 


-0.27 


81 


4.41 


4.32 


-0.09 


82 
83 


5.25 
5.22 


5.29 
4.93 


+0.04 
-0.29 


85 


4.91 


4.7-9 


—0.12 


91 

92 


4.48 
4.49 


4.64 
4.51 


+0.16 
+0,02 



PHOTIC REACTIONS OF HONEY-BEE 391 

VII. VARIABILITY OF PHOTIC RESPONSE 

The honey-bee is remarkably constant in the strong positive 
phototropism which it evinces. The course of individuals creep- 
ing in directive light is a straight path toward the source. Yet, 
as has been shown, occasional departures from this behavior do 
occur. In non-directive light, moreover, the responses of normal 
bees are frequently extremely variable. The animal may turn 
markedly toward a given side in one trial, and in the next, turn 
quite as markedly toward the opposite side. Again, the direc- 
tion of turning may be completely changed several times in the 
course of a single trial. 

It is not surprising, therefore, that bees with one eye blackened 
also exhibit considerable variability of response in both directive 
and non-directive illxunination. In non-directive light particu- 
larly, there were a munber of cases in which animals turned little 
or not at all toward the functional eye, while there were still 
others in which they circled chiefly toward the covered eye. In 
fact, over 25 per cent of the first four pairs of determinations on 
the fifty-two bees, when averaged, gave negative values. These 
departures from the more usual tendency, to turn toward the 
functional eye, sometimes characterized the entire behavior of 
an individual; again, they appeared only spasmodically. 

Thinking that some of the results above mentioned might be 
attributed to a loss of phototropism, either permanent or extend- 
ing over a considerable interval of time, I frequently subjected the 
animals exhibiting them to one or more immediate trials in direc- 
tive light. This, however, failed to show anything which might 
be construed as a loss of phototropism. The variations of 
response noted, therefore, must be referred to external and internal 
factors which are capable of modifying, in a more or less profound 
way, the dominating effect of unilateral photic stimulation. 
Such factors are of two sorts, those which are continuously effec- 
tive and those which are not continuously effective, but fluctuate 
from time to time. Both types played so considerable a role in 
the experiments previously described, .that I have felt they mer- 
ited the somewhat extended analysis presented in the following, 
pages. 



392 DWIGHT E. MINNICH 

1. Continuous factors 

a. Temperature and humidity. Of the continuously operative 
factors, none are more important than the general conditions of 
temperature and humidity. These profoundly affect the activity 
of bees. Mclndoo ('14, p. 279) says: "Climatic conditions per- 
ceptibly affect the activity of bees. When it is extremely warm, 
they are most active and are rarely quiet even for a few seconds. 
When it is moderately warm, they are less restless, and when 
rather cool, bees do not move freely." Again he says: "During 
cool weather their movements are quite sluggish, and when the 
humidity is high they are much less active and respond to vari- 
ous odors more slowly than when there is low humidity." 

Precisely the same effects were noted in the present experi- 
ments. So serious did they become on several occasions that the 
experiment had to be abandoned. On cool, damp days bees 
were apt to be quite unreactive, and prolonged exposure to light 
often failed to induce locomotion. Considerable mechanical stim- 
ulation might call forth creeping, but it was of desultory kind 
and was apparently unaffected by photic stimulation. There can 
be no doubt, therefore, that general weather conditions consid- 
erably affect the behavior of bees toward light. Since some 
experiments were continued under less favorable weather con- 
ditions, it is quite probable that they account for some of the 
aberrancies observed. 

b. After-effects. In making quantitative determinations in 
non-directive hght, trials were frequently made in the two inten- 
sities in rapid succession. Although the bee was always exposed 
for at least thirty seconds to a given intensity before making a 
test, there still existed the possibility that an after effect of the first 
intensity might influence the behavior of the animal in the sec- 
ond. Thus Herms ('11, p. 215) has demonstrated an after-effect 
of photic stimulation in the blow-fly larva, which may manifest 
itself in the continued orientation of the animal for as much as 
fifteen to twenty seconds after the cessation of the stimulus. 
That such is not the case for bees, however, is very clearly dem- 
-onstrated by the following experiment. 



PHOTIC KEACTIONS OF HONEY-BEE 393 

Normal bees were allowed to creep on a strip of smoked paper 
toward the 80-c.p. incandescent lamp. When, after creeping a 
distance of about 60 cm., the bee reached a point 40 cm. from the 
source of light, the lamp was extinguished. Not only was the 
current turned off, but a screen was simultaneously placed before 
the lamp, so that even the slight after-glow of the filaments was 
eliminated. After ten seconds of total darkness the light was 
turned on and the bee removed. Two to four records were made 
of each of eleven animals in this manner. In not one case did 
the bee fail to lose its orientation within at most a couple of 
seconds after the extinction of the light. Often the loss of ori- 
entation was almost, if not quite, simultaneous with the cessa- 
tion of the stimulus. The deviation from the former orienta- 
tion was sometimes marked by a pronounced tendency to turn 
toward one side, with the result that the animal crept in circles 
in the dark. At other times the bee merely wandered, turning 
first in one direction, then another. Typical records of two ani- 
mals are reproduced in figure 16. There is, therefore, no after- 
effect of photic stimulation in the honey-bee, and this does not 
account for any of the irregularities observed. 

c. Failure to eliminate photoreceptor. The difficulties in manipu- 
lating bees necessitate relying upon a single operation to elimi- 
nate completely the function of the compound eye. Although in 
this operation great care was exercised to cover the eye com- 
pletely with a heavy coat of paint, there is a possibility that in a few 
cases this was not accomplished. Moreover, from the moment 
the animal began to recover from the anaesthetic, the covered 
eye was repeatedly subjected to vigorous scrapings by the front 
leg of the same side. While the examination of a number of 
animals after experimentation showed that this seldom resulted 
in a removal of any of the eye covering, it probably succeeded in 
doing so in a few cases. Occasionally, also, the varnish cracked 
somewhat on drying. These unavoidable failures to keep the 
compound eye entirely free of light, undoubtedly modified, to a 
greater or less extent, not a few of the results obtained. 

Beside the failure to cover the eye, there is the possibility that 
the three ocelli of the honey-bee are concerned in its photic 



394 



DWIGHT E. MINNICH 




Fig. 16 Smoked-paper records of two normal bees creeping toward a liglit 
source (upward in the figure). As the animals reached the line indicated by the 
letter P the light was extinguished. Note the extremely rapid h)ss of orientation, 



PHOTIC REACTIONS OF HONEY-BEE 395 

behavior. In blackening the compound eye I made no attempt to 
cover the oceUi, but afterward in examining the specimens used, 
I found that sometimes all, sometimes only one or two, at other 
times none of these organs had been covered. If the ocelli do 
exercise any considerable function, therefore, there was involved 
here a variable of no small magnitude. 

It is also possible that in bees other portions of the body, or 
even the entire integument, may be photosensitive. Photoder- 
matic sensitivity is not unknown among arthropods. It has 
been reported by Graber ('84) for the cockroach, by Plateau ('87) 
for two species of blind myriapods, and by Stockard ('08) for the 
walking-stick. 

In order to find out if these several possibilities were affecting 
results, I conducted several experiments with bees both eyes of 
which had been carefully covered with a thick coat of 'Jap-a-lac' 
On the morning after the operation, each bee was placed in a 
separate cage in non-directive illumination of 957 mc. Although 
with one or two exceptions the bees were quiet when first exposed 
to the light, within fifteen minutes all had become thoroughly 
active, showing clearly that they were not free from the activat- 
ing effect of the light. 

At the conclusion of the above test the same bees were individu- 
ally subjected to trials in the directive light area. Here they 
looped and turned in a variety of ways, some circling more or less 
constantly toward a given side, not unlike bees with only one 
eye blackened. Despite most devious courses, however, they 
sooner or later managed to work their way to the general region 
of the source of light. It is quite clear, therefore, that photore- 
ception had not been entirely abolished, although both com- 
pound eyes had been covered as carefully as possible. 

Which of the several explanations advanced accounts for these 
results, is not certain. I am disposed to believe that the failure 
to eliminate the compound eyes completely was chiefly, perhaps 
solely, responsible. However that may be, it is certain that in 
this, as well as in other experiments, the incomplete suppression 
of photic stimulation was the source of a large amount of varia- 
tion in the results obtained. 



396 DWIGHT E. MINNICH 

d. Effect of contact stimulus. The effect of the contact stimu- 
lus afforded by the blackening material on the eye and the adja- 
cent parts of the head must also be recognized as a considerable 
factor in modification of photic behavior. The influence of this 
stimulus has been clearly demonstrated by DoUey ('16, pp. 394- 
397) on Vanessa antiopa. With one eye blackened, this butter- 
fly, when creeping in total darkness, turned, with few exceptions, 
continuously toward the blinded eye. The tendency to circle 
was often quite pronounced, and showed little or no modification 
from day to day. The effect of contact stimulus on the covered 
eye was, therefore, antagonistic to that produced by light on the 
opposite, functional eye. 

I tried experiments with the honey-bee similar to those car- 
ried out by Dolley on Vanessa. Bees with one eye blackened 
were allowed to creep on smoked paper in total darkness. Un- 
fortunately, the trials were of such duration that the bee recrossed 
its course many times. This made it quite impossible to decipher 
the records, and I have not since had an opportunity to repeat the 
experiments. It is not unlikely, however, that the effect of con- 
tact stimulus on the eye of the bee is similar to that demonstrated 
for Vanessa. If such be the case, it probably accounts for much 
of the circling toward the covered eye, which was evinced by 
numerous individuals particularly in non-directive light. 

e. Asymmetry of the animal. As was previously pointed out, 
normal bees frequently exhibited a marked tendency to turn more 
or less constantly toward the right or left when creeping in non- 
directive light. Such tendencies are doubtless due to a lack of 
perfect symmetry on the part of the animal. The asymmetry 
may be physiological; it may be anatomical. It may consist of 
a differential sensitivity of the photoreceptors on the two sides 
of the body, as Patten ('14, p. 259) has suggested, or it may be due 
to an inequality of any two symmetrically located elements of 
the neuromuscular mechanism. Under the influence of directive 
light, these idiosyncracies are, as a rule, continually corrected. 
In non-directive illumination or total darkness, however, they at 
once assert themselves. Since the eye to be blackened was always 
chosen so that the effect of photic stimulation would be opposite 



PHOTIC EEACTIONS OF HONEY-BEE 397 

to that exerted by natural asymmetry, many failures to turn 
toward the functional eye are probably thus accounted for. 

/. Modifiability through experience. The work of Axenfeld, 
Holmes, Brundin, and Dolley has shown that a number of ar- 
thropods are able to modify their photic behavior through expe- 
rience. The same is true of the honey-bee, at least in directive 
light, as the following experiment shows. Each of a number of 
normal bees, selected on the basis of the accuracy with which they 
oriented to directive light, had one eye blackened. On the fol- 
lowing day those animals which exhibited a more or less pro- 
nounced tendency to loop toward the functional eye were sub- 
jected to trials (twenty to twenty-five in number) in the directive 
light area. 

Bees which displayed little or no tendency to loop were given 
several trials to ascertain if their behavior was constant, and then 
discarded. These animals may have been able to modify their 
behavior almost immediately, or their failure to exhibit circus 
movements may have been due to an imperfect covering of the 
eye, or to the effect of contact stimulus. 

Of those bees which did perform circus movements, records 
were taken about every ten to twenty minutes from 9 a.m. to 
5 P.M., with the exception of about an hour at noon. Ten bees 
were thus tested. Four of these animals displayed a steady and 
marked improvement in the course of the trials. Two others 
showed some improvement, although considerably less than the 
first four. Two more of the ten improved for a time, only to 
regress again, so that while a number of trials near the middle of 
the series were somewhat modified, those at either end were 
much alike in the number of loops performed. The last two bees 
showed practically no improvement, although in one of the ani- 
mals the tendency to circle was at no time very pronounced. It 
is quite certain, therefore, that at least some bees are able to mod- 
ify their responses to directive light through experience . 

The records shown in figure 17 afford a striking example of this 
modifiability. Although in its first trials the animal looped re- 
peatedly as it crept toward the light, it was subsequently able to 
reach the light by a nearly straight course. This animal, how- 



D WIGHT E. MINNICH 




Fig. 17 Records of a bee with the left eye blackened, in directive light, show- 
ing modifiability of behavior through experience. Alternate records from a 
series of twenty-six are shown in the figure. 



PHOTIC EEACTIONS OF HONEY-BEE 399 

ever, as well as the others, usually circled again toward the func- 
tional eye upon reaching the non-directive region near and 
directly beneath the lamp. The records shown in the figure do 
not include this region. 

DoUey ('16, p. 402) states that he observed some modification 
from day to day in the behavior of Vanessa in non-directive light. 
The following evidence seems to indicate that the same is true, 
to at least some extent, for the honey-bee also. In directive 
light, individuals with one eye covered were sometimes observed . 
to begin to swerve toward the functional eye, only to check them- 
selves by a sharp turn in the opposite direction. Correcting 
movements of this sort sometimes occurred repeatedly in a single 
trial, with the result that the animal reached the source of light 
by a much more direct course than it would have otherwise been 
able to follow. Precisely the same sharp turns away from the 
functional eye were occasionally seen in non-directive light also. 
It seems probable, therefore, that modifiability through experi- 
ence affects the behavior of bees in non-directive as well as in 
directive light. 

B. Fluctuating factors 

The variables which have thus far been discussed are those 
which continuously or progressively affect the behavior of bees 
throughout an experiment. They probably account in a large 
measure for such phenomena as the persistant turning toward 
the covered eye in certain individuals or the apparent lack of any 
tendency to turn at all in still others. They do not, however, 
explain the many sudden changes of behavior which were ob- 
served. Such variations are dependent upon factors of behavior 
which fluctuate from time to time. A few of these factors result 
from environmental changes. The majority, however, arise from 
changes within the organism itself. 

a. External. In quantitative experiments every possible pre- 
caution was exercised to keep all external factors uniform, except 
the intensity of the light which was changed from trial to trial. 
This, of course, was possible to a limited extent only. The 
manipulation of the bees introduced varying mechanical stim- 



400 DWIGHT E. MINNICH 

uli which were quite unavoidable. An animal was accidentally 
pressed slightly in changing it from one cage to another, or, fail- 
ing to react to photic stimulation, the cage had to be shaken. 
Again, in transferring a bee from the light to which it was sub- 
jected for activation to the center of the non-directive light cham- 
ber, it was subjected to increases and decreases of light intensity. 
All of these details and endless others, collectively and individu- 
ally, were undoubtedly responsible for many of the sudden 
variations of behavior which occurred. 

b. Internal. The chief causes of irregular variations, however, 
are internal. When under constant external conditions, a bee 
varies the direction of its turning several times in the course of a 
single trial, the behavior must be attributed to changes within the 
animal itself, the physiological states of Jennings ('06). Gener- 
ally speaking, the analysis of these changing physiological states 
is difficult or impossible. In several instances, however, I was 
able to make a fairly certain diagnosis. I may cite several 
examples. 

Bee no. 147 was subjected to the usual quantitative experi- 
ment in non-directive light. From the beginning this animal 
exhibited a rapid, uneasy locomotion. Its entire behavior may 
best be described by the word 'excitable.' In the course of the 
first day after the eye was blackened, five pairs of determinations 
were made. In 24 mc. light, the animal circled chiefly toward 
the covered eye, while in 957 mc, its behavior varied from one 
set of records to another. 

On the following morning, the first pair of determinations was 
begun at 9:49. The bee circled markedly toward the covered 
eye in both intensities of light. At 12:14, a second pair of 
determinations was begun. In making the first trial, the bee 
rushed about its cage for some minutes before finally creeping up 
into the non-directive light chamber. When it did appear, it 
seemed greatly excited and crept very rapidly. As the series of 
records progressed, the animal circled more and more pronouncedly 
toward the functional eye, the locomotion grew more rapid, and 
a continuous buzzing began. The performance of small circles 
toward the functional eye in 24 mc. light was surprising, for in 



PHOTIC EEACTIONS OP HONEY-BEE 401 

all previous record sets for this intensity, the animal had shown a 
more or less pronounced tendency to circle toward the covered 
eye. In the course of the fourth trial in 957 mc. light, the bee 
had reached a state of intens.e excitation. Its turning became so 
rapid, and the consequent circles so small, that at length the 
animal tumbled over on its back. Defaecation occurred. Mean- 
while it continued buzzing loudly, and, though lying on its back, 
managed to whirl round and round toward the functional eye. 

After the trial just described, the animal was allowed to rest for 
two hours. At 2:44 and 4:10, respectively, two more pairs of 
determinations were made. The bee continued to circle markedly 
toward the functional eye in 957 mc. light, and more or less toward 
the functional eye in 24 mc. light. The 'excitement' which had 
characterized the previous trials, however, was absent, and the 
animal manifested signs of weakness and exhaustion. 

In the behavior of this animal there was a sudden^ — even vio- 
lent — increase of phototropism. This was probably due to an 
unusual intensification of activity. I have repeatedly observed 
the close correlation between these two features of behavior in 
bees. As a rule, the greater the activity, the more pronounced 
is the manifestation of phototropism. The increase of activity 
in this animal was produced by a state of metaboUsm, entailed 
by a collection of faeces in the intestine. That such' a condition 
may affect the activity of bees to a marked degree is evidenced by 
the following statement made by Phillips and Demuth ('14, p. 
12) in connection with a study of certain hive conditions in win- 
ter. "It therefore appears that the accumulation of feces (in 
the intestine) acts as an irritant, causing the bees to become more 
active and consequently to maintain a higher temperature." 

In several other animals defaecation occurred in the course of 
a trial without being preceded by any conspicuous change of 
behavior. Neither the amount voided nor the force of expulsion, 
however, gave any evidence of long accimaulation or intestinal 
irritation in these cases. It seems reasonably certain, therefore, 
that the sudden increase of phototropism exhibited by bee no. 
147 was due to the accumulation of faeces in the intestine. 



402 D WIGHT E. MINNICH 

There were likewise certain other physiological conditions 
which seemed to intensify photic reactions. Thus bees, upon first 
recovering from anaesthesia, were frequently observed to creep 
in very small circles toward the functional eye. Bees, which 
throughout an experiment appeared physically weak, were also 
apt to be more intense in their positive deflections. Examples 
of this latter behavior were afforded by bees nos. 77 and 92. 
Again, individuals which appeared vigorous at the beginning of 
an experiment, but became weak and moribund toward the end, 
generally showed a progressive increase in their circus movements. 
For example, bee no. 91 circled rather strongly toward the cov- 
ered eye at first. In the course of the experiment, the animal 
became weak. Correspondingly, its average deflections became 
more and more positive until, just before being discarded, it was 
turning at the rate of +23.82°/cm. in 957 mc. light. 

These instances demonstrate the profound manner in which 
internal factors are capable of modifying photic behavior. As a 
rule, only the change in behavior is noted. The recognition of 
the internal state which conditions this outward expression is 
possible only in extreme cases. Nevertheless, I believe that these 
internal factors were directly responsible for most of the sudden 
variations which characterized the behavior of so many bees. 

Thus far we have tacitly assumed that the honey-bee is a purely 
reflex organism. It is not the purpose of the present paper to 
discuss the mooted question of psychic powers in this animal. It 
may be said, however, that the opinion advanced by Bethe ('98), 
that the behavior of bees affords no evidence of psychical attri- 
butes, has not met with extensive approbation. Forel ('07) and 
V. Buttel-Reepen ('07), in particular, have presented consider- 
able evidence to show that bees are something more than mere 
reflex machines. 

V. Buttel-Reepen ('07, p. 23) has shown that after bees have 
been deadened with chloroform, ether, saltpeter, puffball, etc., 
their memory for location entirely disappears. Subsequently they 
may again 'learn' the position of the hive, etc., but for the time 
at least, "they have forgotten everything previously known." 
My own observations have shown that during recovery from an 



PHOTIC REACTIONS OF HONEY-BEE 403 

anaesthetic and in weakened or moribund conditions the photic 
responses of bees become more intense. Photic behavior, how- 
•ever, is probably largely reflex in character. It would appear, 
therefore, that the same conditions which occasion a loss of 
'memory' or other central function and the like cause the reflex 
phases of behavior to appear more boldly. In other words bees, 
though fundamentally reflex, may possess certain rudiments of 
higher behavior. Under the influence of narcotics and anaes- 
thetics or in moribund conditions, these factors cease to affect 
behavior, and the animal is reduced to a simple reflex condition. 
If this be correct, we have here an important variable to account 
for modifications of photic behavior. 

3. Summary 

The variability of respdnse displayed by bees with one eye 
blackened when creeping in non-directive light is never due to a 
permanent loss of phototropism or to after-effects of one inten- 
sity upon trials in a second intensity. It is attributable to the 
following causes: 

a. Conditions of temperature and humidity. 

b. Failure to eliminate completely the photoreceptors on one 
side of the body. 

c. Effect of contact stimulus afforded by the eye covering. 

d. Natural asymmetry of individuals. 

e. Modifiability through experience. 

/. Mechanical stimuli attendant upon manipulation. 
g. Internal factors which affect behavior variously from time 
to time. 

VIII. NATURE OF PHOTIC ORIENTATION 

1. Theories 

In recent years the photic behavior of lower animals has been 
the subject of two theories, respectively known as the 'continuous 
action theory' and the 'change of intensity theory.' The 'con- 
tinuous action theory,' as its name implies, postulates a continu- 
ous action of light upon the organism, orientation resulting when 



404 DWIGHT E. MINNICH 

such action is equal on the symmetrical photoreceptors of oppo- 
site sides of the body. In its present form this theory is perhaps^ 
best summed up by Loeb ('16, p. 259). "If a positively heho- 
tropic animal is struck by light from one side, the effect on tension 
or energy production of muscles connected with this eye will be- 
such that an automatic turning of the head and the whole animal 
towards the source of light takes place; as soon as both eyes are 
illuminated equally the photochemical reaction velocity will be 
the same in both eyes, the symmetrical muscles of the body will 
work equally, and the animal will continue to move in this direc- 
tion. In the case of the negatively heliotropic animal the picture- 
is the same except that if only one eye is illuminated the muscles- 
connected with this eye will work less energetically." 

The 'change of intensity theory,' however, accounts for ori- 
entation in an entirely different manner. According to it, the proc- 
ess depends not upon the continuous action of light, but upon 
the intermittent action of rapid changes in its intensity (Jennings 
'04, '06, '09; Mast, '11). In positive organisms the effective- 
stimulus is assumed to be a sudden decrease of intensity on the 
photoreceptor; in negative organisms, a sudden increase. A 
photopositive animal, such as the honey-bee, for example, orients- 
and maintains its orientation through sudden swervings away from 
the side experiencing a decrease of illumination, and orientation 
is attained when neither eye is undergoing such a decrease. A 
similar explanation is applied to photonegative organisms except 
that the effective stimulus for them is assumed to be an increase 
of intensity. 

There is thus a wide diversity in the explanations of orientation 
offered by these two theories. In the concluding pages of this 
paper, therefore, I propose to discuss the evidence afforded by 
my own experiments, as well as that afforded by the observations 
on circus movements in general, with a view to ascertaining 
which of the two theories more correctly applies to the orienta- 
tion of arthropods. 



PHOTIC REACTIONS OP HONEY-BEE 405 

£. Orientation in the honey-bee 

As has been previously stated, the process involved in circus 
movements must be regarded as identical in every respect with 
that involved in normal orientation. The circus movement is 
the orienting process. A normal creeping bee may be caused to 
■ perform circus movements without having one eye blackened, 
if the light is merely moved so as to keep it constantly to one side 
of the animal. Whether the eye be blackened or the light be 
moved, the case is the same. The orienting process is merely pro- 
longed, and the final attainment of orientation prevented. 

The experimental data detailed in the present paper show con- 
clusively that when one eye of a bee is blackened, the resulting 
circus ihovements are produced by the continuous action of the 
light upon the functional photoreceptor. In the experiments in 
non-directive light, the only photic stimulation afforded was one 
of constant, almost uniform intensity over the entire surface of 
the eye. Under such conditions, the animals not only performed 
circus movements toward the functional eye, but the amount of 
turning increased with an increase in the stimulus. It is clear, 
therefore, that the process of normal orientation, which is iden- 
tical with that involved in the circus movement, must also be 
dependent upon the continuous action of light. 

The impulses arising from this stimulation are, at least in part, 
transmitted to the musculature of the opposite side of the body, 
since upon hemisecting the brain, the bee suffers a complete loss 
of phototropism (Holmes, '01, p. 227). Although his experi- 
ments were not conclusive on the point, Holmes believed that 
the result obtained was not entirely due to "the effect of the 
shock of the operation, or of incidental injury to other paths of 
photic impulses." It must, therefore, have been due to the sev- 
erance of crossed tracts or commissures which served in the trans- 
mission of such impulses. There are present in the dorsocerebron 
of the bee at least three commissures in more or less intimate 
connection with the optic tracts (Kenyon, '96), and it is possible 
that these are the elements concerned. There is thus neurologi- 
cal as well as physiological evidence for the crossed transmission 
of photic impulses. 

THE JOURNAL OF BXPEBIMENTAL ZOOLOOT, VOL. 29, NO. 3 



406 DWIGHT E. MINNICH 

The resultant effect of these impulses on the opposite side of 
the body is most probably an increase in the tonus of the extensor 
muscles. I have no direct evidence on this point in the case of 
the honey-bee. However, Holmes ('05) and Holmes and 
McGraw ('13), in experiments deaUng with unilateral stimulation 
of photopositive insects, frequently observed that the legs on. 
the side away from the stimulated eye were strongly extended, 
while those on the same side exhibited a pronounced flexion. 
Recently, Garrey ('17) has published an account of numerous 
experiments in which the same phenomenon was observed. In 
such animals it is clear that orientation is effected through a 
difference in the posture and not through a difference in the speed 
of the legs on the two sides of the body. This conclusion is 
further substantiated by the results obtained by DoUey ('17) on 
Vanessa. Careful measurement of the velocity of these butter- 
flies showed that they did not creep faster in a very intense 
illumination than they did in a fairly weak one. From the above 
observations, therefore, it is clear that in many insects orienta- 
tion is effected through changes of tension in the leg muscles. As 
previously stated, I have not been able to observe any constant 
and pronounced difference in the muscular tension on the two 
sides of the body in the honey-bee, although I have made only 
casual observations in this direction. I do believe that orienta- 
tion is produced in this manner, however, and that the failure 
to detect it was due to the slight degree of the tensions together 
with the extreme rapidity of their execution. 

This attempt to analyze the process of orientation in the honey- 
bee is, of course, far from complete. Certain features of it, how- 
ever, may be defined with reasonable certainty. Thus it is 
clear that the stimulus regulating photic orientation is continu- 
ous and not intermittent. Furthermore, it appears to be essen- 
tial that at least some of the impulses arising in the eye be 
transmitted to the opposite side of the body, where they probably 
regulate the tonus of the extensor muscles. As far as it is known, 
therefore, the process of orientation in the honey-bee is in strict 
conformity with the 'continuous action theory.' 



PHOTIC REACTIONS OF HONEY-BEE 407 

3. General evidence 

In experimenting with locomotor organisms, it is not an easy 
matter to regulate absolutely the conditions of photic stimulation. 
Thus, a photopositive animal as it moves toward the light is 
acted upon continuously by the light. But it is also subjected 
not only to a gradual increase of intensity with every forward 
movement, but also to sudden decreases and increases with every 
lateral deviation, however slight. Whether the orientation of 
the organism, therefore, is effected through a continuous action 
of the stimulus or only through sudden changes in its intensity 
from time to time, is frequently difficult to determine with cer- 
tainty. This difficulty in separating the two conditions experi- 
mentally has led to much confusion in solving the problem of 
orientation. Among arthropods, however, there is a growing 
body of evidence tending to show that orientation is produced by 
continuous photic stimulation and not by intermittent changes of 
intensity. 

No stronger evidence is to be found in this connection than 
that afforded by the general phenomenon of circus movements. 
The importance of this evidence has been repea1;edly emphasized 
by Parker ('03, '07), Loeb ('06, '13), Bohn ('09 a, b). Holmes 
and McGraw ('13), Garrey ('17), and others. Parker ('07, p. 
548), in reviewing one of the earlier expositions of the 'change of 
intensity theory' (Jennings, '06), states the case clearly when he 
says, "If the modem tropism theory were as weak as Jenning's 
would have us beheve, the experimental evidence upon which it 
rests ought easily to be explained away. Yet it has always 
seemed to the reviewer that the characteristic circus movements 
performed by animals immersed in a homogeneous stimulant, 
but with sense organs unilaterally obstructed, are explainable 
only on the basis of this theory." 

This statement is certainly justified by the facts.. Circus 
movements seem quite incapable of explanation in terms of the 
'change of intensity theory' of orientation. Let us examine the 
case of a photopositive arthropbd, with the right eye blackened, 
as it creeps toward a source of Hght. From experiment we know 



408 DWIGHT E. MINNICH 

that such an individual usually loops to the left. As it does so, 
however, the functional eye experiences a pronounced decrease 
of stimulation during the first half of each loop. According to 
the 'change of intensity theory,' such decreases should result in 
swerves toward the opposite side. Such, however, do not occur, 
as a rule. The animal, instead, completes the loop. It, there- 
fore, does not respond very strongly to a decrease of intensity. 
If it did, the performance of circus movements would be quite 
impossible. If we assume, however, that the looping is produced 
by the continuous inequality in the stimulation received by the 
two eyes, the asymmetry of response becomes intelligible at once. 
For, in an animal with one eye blackened, the functional eye, 
even when turned farthest fl-bm the light, is the recipient of some 
stimulation, whereas the covered eye receives none whatever. 

It may be objected, however, that many positive arthropods 
with one eye blackened are able to overcome their tendency to 
circle in directive hght, and that this is a response to the decrease 
of intensity on the functional eye at the beginning of each loop. 
Such may well be the case, as Holmes ('05, p. 345) has suggested. 
This is a matter for further experiment to decide. In any case, 
however, circus movements must be regarded as an established 
phenomenon of general occurrence among this group of animals. 
The significant thing, therefore, to an understanding of orienta- 
tion is to discover what is effective in producing these reactions 
rather than what is effective in modifying them. 

The evidence afforded by circus movements in directive light 
as to the natiu-e of the stimulus concerned in their production is 
thoroughly corroborated by the results obtained in non-directivie 
light. Under the conditions of non-directive illumination em- 
ployed by Holmes and McGraw ('13) and by myself, an animal 
is absolutely free from any pronounced or consistent changes in 
the intensity of the stimulus to which it is subjected. More- 
over, the experiments of Dubois ('86) on the beetle Pyrophorus 
furnish a case in which there is no possibility whatever of inten- 
sity changes playing a significant role in orientation, since the 
source of hght is within the animal itseK. Yet in all these cases 
the elimination of one eye was usually followed by typical circus 



PHOTIC REACTIONS OF HONEY-BEE 409 

movements toward the functional eye. In the absence of signifi- 
cant intensity changes, these responses must have been produced 
through the continuous action of hght. The correctness, of this 
conclusion is further attested by the fact that bees with one eye 
blackened tend to circle more toward the functional eye in a non- 
directive light of high intensity than in one of low intensity. The 
response may thus be made to vary with the intensity of a con- 
stantly acting stimulus. 

Bohn ('09, a, '09 b) has suggested circus movements as a cri- 
terion for tropisms. Certainly, if the photic orientation of an 
animal is the result of a continuous action of the light on both 
eyes, as the tropism hypothesis postulates, the eUmination of one 
eye should produce circus movements. The form of response 
will, of course, be subject to the peculiarities of locomotion. 
However, the ehmination of the photoreceptors on one side of 
the body should result in a more or less asymmetrical response 
toward or away from that side, depending upon the index of pho- 
totropism. A failure to obtain such responses means either that 
the orienting stimulus does not consist in the continuous action 
of light or that modifying factors are present which interfere 
with the expected respojise. As stated in the introductory pages 
of this paper, the failures to obtain circus movements which have 
thus far been reported, are, I believe, to be attributed to the lat- 
ter rather than to the former cause. 

In conclusion, we may say that circus movements, both in direc- 
tive and non-directive illumination, are produced by the con- 
tinuous action of light and not by intermittent changes in its 
intensity. This, together with the general occurrence of cir- 
cus movements among arthropods and the close relationship of 
such responses to normal orientation afford strong evidence that 
in this group of animals photic orientation is normally produced 
through the continuous action of light. This does not mean that 
photosensitive arthropods do not respond to sudden changes in 
illumination. They undoubtedly do. The orientation of the 
body toward or away from a source of light, however, cannot be 
fundamentally the result of such responses. 



410 DWIGHT E. MINNICH 

IX. GENERAL SUMMARY AND CONCLUSIONS 

1. Light exerts a kinetic influence upon the honey-bee; that 
is, it tends to induce activity. In its absence, on the other hand, 
activity is either greatly reduced or entirely lacking. 

2. Isolated worker bees, in an active condition, exhibit strong 
positive phototropism when flying or creeping. Temporary 
suppressions of this response may occur, however. 

3. Normal bees when creeping in non-directive hght usually 
exhibit pronounced asymmetrical responses of constant or varia- 
ble index. Since essentially the same responses occur in total 
darkness, they are not fundamentally dependent upon photic 
stimulation. They are probably, therefore, conditioned largely 
by internal factors. 

4. Bees with one eye blackened usually loop toward the func- 
tional eye as they creep toward a source of light. Some indi- 
viduals are found, however, which display little tendency to loop, 
and occasionally an animal loops toward the covered eye. In the 
absence of experience, the tendency to loop toward the functional 
eye remains a permanent feature of behavior. 

5. In non-directive hght, bees with one eye blackened gener- 
ally circle toward the functional eye, although a number are 

ound which circle more or less toward the covered eye. 

6. Although subject to considerable variation, bees with one 
eye blackened tend, in general, to circle more toward the func- 
tional eye in non-directive hght of 957 mc. than in one of 24 mc. 
This tendency may be manifested in : 

a. A lesser amount of turning toward the covered eye in the 
intense hght than in the less intense one. 

h. A greater amount of tiu-ning toward the functional eye in the 
more intense Hght than in the less intense one. 

7. Since circus movements not only occur in a uniform, non- 
directive hght field, but also vary in amount with the inten- 
sity of the hght, they are produced by continuous unilateral 
stimulation. 

8. In bees with one eye blackened, the rate of locomotion, 
unlike the amount of turning, is not dependent upon the intensity 
of photic stimulation. 



PHOTIC REACTIONS OP HONEY-BEE 411 

9. The variability of response displayed by bees with one eye 
blackened, when creeping in non-directiVe Ught, is never due to 
a loss of phototropism or to after-effects of one intensity upon 
trials in a second intensity. It is attributable to the following 
causes : 

a. Conditions of temperature and humidity. 
h. Failure to eliminate completely the photoreceptors on one 
side of the body. 

c. Effect of contact stimulus afforded by the covering of eye. 

d. Natural asymmetry of individuals. 

e. Modifiability through experience. 

/. Mechanical stimuli attendant upon manipulation. 
g. Internal factors which may affect behavior from time to 
time, but not necessarily continuously. 

10. Photic orientation in the normal honey-bee is effected 
through the continuous action of light on both photoreceptors. 

11. The following considerations afford strong evidence that 
among arthropods generally, orientation to light is effected 
through the continuous action of the stimulus rather than inter- 
mittent changes of its intensity. 

a. Circus movements are of general occurrence among photo- 
tropic arthropods. 

h. The process involved in circus movements is identical with 
that involved in normal orientation. 

c. Circus movements in directive Ught are explainable only on 
the assumption of continuous photic stimulation. 

d. Circus movements are performed under conditions of non- 
directive illumination where the only stimulus afforded is on& 
of approximately constant intensity. 

12. Circus movements, as Bohn has suggested, furnish a cri- 
terion for testing the 'continuous action theory' of orientation.. 
The failure of the test, however, does not necessarily invalidate' 
the theory. 

Postscript. The preparation of this paper has been much 
retarded by the absence of the author, who is still in government 
service in France. Hence it has not been possible to include im 
the discussion Carrey's recent paper (Jour. Gen. Physiol., vol. 1„ 



412 DWIGHT E. MINNICH 

p. 118), in which he has shown that the diameter of the circle m 
circus movements varies with changes in light intensity, nor 
Loeb's most recent volume on "Forced Movements, Tropisms, 
and Animal Conduct." 

X. BIBLIOGRAPHY 

AxENPBLD, D. 1899 Quelques observations sur la vue des arthropods. Arch. 

ital. de bioL, t. 31, pp. 370-376. 
Bethb, a. 1897 a Das Nervensystem von Carcinus maenas. Arch. f. mikr. 

Anat., Bd. 50, S. 460-546. 

1897 b Vergleichende Untersuchungen iiber die Functionen des Cen- 
tralnervensystems der Arthropoden. Arch. f. d. ges. Physiol., Bd. 68, 
S. 449-545. 

1898 Dtirfen wir den Ameisen und Bienen psychische Qualitaten 
zuschreiben? Arch. f. d. ges. Physiol., Bd. 70, S. 15-100. 

BoHN, G. 1909 a La naissance de I'intelligence. Paris. 350 pp. 

1909 b Les tropismes. VIme Congrfis International de Psychologie. 
Genfeve. Rapports et Comptes rendus, pp. 325-337. 

Bktjndin, T. M. 1913 Light reactions of terrestrial amphipods. Jour. Animal 
Behavior, vol. 3, pp. 334^352. 

Btjttbl-Rbbpen, H. v. 1907 Are bees reflex machines? Experimental con- 
tribution to the natural history of the honey-bee. Translated by 
Mary H. Geisler. Published by A. I. Root Co., Medina, O. 48 pp. 

Cabpbntbr, F. W. 1905 The reactions of the pomace fly (Drosophila ampelo- 
phila Loew) to light, gravity, and mechanical stimulation. Amer. 
Nat., vol. 39, pp. 157-171. 

1908 Some reactions of Drosophila, with special reference to convul- 
sive reflexes. Jour. Comp. Neur. and Psych., vol. 18, pp. 483-491. 

Davbnpoet, C. B. 1897 Experimental morphology. Part 1. New York, 
xiv + 280 pp. 

Dollby, W. L., Jr. 1916 Reactions to light in Vanessa antiopa, with special 
reference to circus movements. Jour. Exp. Zool., vol. 20, pp. 357-420. 
1917 The rate of locomotion of Vanessa antiopa in different luminous 
intensities and its bearing on the 'continuous action theory' of orienta- 
tion. Anat. Rec, vol. 11, p. 519. 

Dubois, R. 1886 Les 61at6rides lumineux. Bull, de la Soc. Zool. de France, t. 
11, pp. 1-275. 

1909 Discussion sur les tropismes. VIme Congres International de 
Psychologie. Geneve. Rapports et Comptes rendus., pp. 343-344. 

FoRBL, A. 1907 The senses of insects. Translated by MacleodYearsley. Lon- 
don, xiv -|- 324 pp. 

Frandsbn, P. 1901 Studies on the reactions of Limax maximus to directive 
stimuli. Proc. Amer. Acad. Arts and Sci., vol. 37, pp. 185-227. 

Gabbey, W. E. 1917 Proof of the muscle tension theory of heliotropism. Proc. 
Nat. Acad. Sci., vol. 3, pp. 602-609. 



PHOTIC REACTIONS OF HONEY-BEE 413 

GoEZE, J. A. E. 1796 Belehrung iiber gemeinnutzige Natur- und Lebenssachen. 

Leipzig. 326 pp. 
Graber, V. 1884 Grundlinien zur Erforschung des Helligkeits- und Farben- 

sinnes der Tiere. Prag. u. Leipzig, viii + 322 pp. 
Hadlby, p. B. 1908 The reaction of blinded lobsters to light. Amer. Jour. 

Physiol., vol. 21, pp. 180-199. 
Herms, W. B. 1911 The photic reactions of sarcophagid flies, especially Lucilia 

caesar Linn, and Calliphora vomitoria Linn. Jour. Exp. Zool., vol. 

10, pp. 167-226. 
Hess, C. 1913 a Gesichtssinn. Handb. der vergl. Physiol, von Hans Winter- 
stein, Bd. 4, S. 555-840. 

1913 b Experimentelle Untersuchungen tiber den angeblichen Far- 

bensinn der Bienen. Zool. Jahrb., Abt. f. allg. Zool., Bd. 34, S. 81-106. 

1917 New experiments on the light reactions of plants and animals. 

Translated by Hilda Lodeman. Jour. Animal Behavior, vol. 7, pp. 

1-10. 
Holmes, S. J. 1901 Phototaxis in the amphipoda. Am. Jour. Physiol., vol. 5, 

p. 211-234. 

1905 The reactions of Ranatra to light. Jour. Comp. Neur. and 
Psych., vol. 15, p. 305-349. 

Holmes, S. J., and MoGraw, K. W. 1913 Some experiments on the method of 
orientation to light. Jour. Animal Behavior, vol. 3, pp. 367-373. 

Jennings, H. S. 1904 Contributions to the study of the behavior of lower or- 
ganisms. Carnegie Inst, of Washington, pub. no. 16. 256 pp. 

1906 Behavior of the lower organisms. New York, xiv -t- 366 pp. 
1909 Tropisms. VIme Congrfes International de Psychologie 
Geneve. Rapports et Comptes rendus, pp. 307-324. 

Kenton, F. C. 1896 The brain of, the bee. Jour. Comp. Neur., vol. 6, pp. 133- 

210. 
LoEB, J. 1890 Der Heliotropismus der Thiere und seine Ubereinstimmung 

mit dem Heliotropismus der Pflanzen. Wiirzburg. 118 pp. 

1906 The dynamics of living matter. New York, xi 4- 233 pp. 
1913 Die Tropismen. Handb. der vergl. Physiol, von Hans Winter- 
stein, Bd. 4, S. 451-519. 

1916 The organism as a whole from a physicochemical viewpoint. 
New York, x -|- 379 pp. 

Lubbock, J. 1882 Ants, bees and wasps. New York, xix + 448 pp. 

Mast, S. O. 1911 Light and the behavior of organisms. New York, xi -|- 
410 pp. 

McIndoo, N. E. 1914 The olfactory sense of the honey-bee. Jour. Exp. Zool., 
vol. 16, pp. 265-346. 

Pabkek, G. H. 1903 The phototropism of the mourning-cloak butterfly, Van- 
essa antiopa Linn. Mark Anniversary Volume, pp. 453-468. 

1907 Jennings on behavior of lower organisms. Science, New Ser., 
vol. 26, p. 548. 

Patten, B. M. 1914 A quantitative determination of the orienting reaction of 
the blowfly larva (Calliphora erythrocephala Meigen). Jour. Exp. 
Zool., vol. 17, pp. 213-280. 



414 DWIGHT E. MINNICH 

Phillips, E. F., and Dbmuth, G. S. 1914 The temperature of the honey bee 

cluster in winter. Bull. U. S. Dept. Agriculture, no. 93, 16 pp. 
Plateau, F. 1887 Reoherches exp6rimentelles sur la vision chez les arthro- 

podes. Ire partie. Bruxelles. 44 pp. 
PoxJCHBT, G. 1872 De I'influence de la lumifere sur les larves diptferes priv6e& 

d'organs ext^rieurs de la vision. Rev. et Mag. de Zool., s6t. 2, t. 23, 

pp. 110-117, 129-138, 183-186, 225-231, 261-264, 312-316. 
RXdl, E. 1901 Untersuchungen iiber die Lichtreactionen der Arthropoden. 

Arch. f. d. ges. Physiol., Bd. 87, S. 418-466. 

1903 Untersuchungen iiber den Phototropismus der Tiere. Leipzig. 

viii + 188 pp. 
Stockakd, C. R. 1908 Habits, reactions, and mating instincts of the 'walking 

stick,' Aplopus Mayeri. Papers from theTortugas Laboratory of the 

Carnegie Institution of Washington, vol. 2, pp. 45-49. 
Tkevirantjs, G. R. 1832 Die Erscheinungen und Gesetze des organischen 

Lebens. Bd. 2, Abt. 1. Bremen. 234 pp. 
Turner, G. H. 1912 The reactions of the mason wasp, Trypoxylon albotarsus 

to light. Jour. Animal Behavior, vol. 2, pp. 353-362. 
Wai/ter, H. E. 1907 The reactions of planarians to light. Jour. Exp. Zool., 

vol. 5, pp. 35-162. 



PHOTIC REACTIONS OF HONEY-BEE 



415 



XI. APPENDIX (TABLE 2) 



A 


B 


c 


D 


E 


F 


Q 


H 


I 


NUMBER 
OF BEB 


NORMAL 
BEE AV." 
PBB CM. 
TO RIGHT 
957 MC. 
LIGHT 


NORMAL 
BBB AV." 
PER CM. 
TO LEFT 
957 MC. 
LIGHT 


ONE EYE 
BLACK AV.° 

PER CM. 
TURNED 24 

MC. LIGHT 


ONE ETE 
BLACK AV." 

PER CM. 

rURNED 957 

MC. LIGHT 


-t- VALUES 

OFE — D 

OBd 


- VALUES 

OFE — D 

OBd 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
24 MC. 
LIGHT 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
957 MC. 
LIGHT 


21 




8.02 


+15.84 


+29.41 


13.67 




30 


30 






10.63 


- 3.00 


+19.33 


22.33 




30 


30 








- 3.22 


+ 2.91 


6.13 




60 


60 








- 2.35 


+ 3.34 


5.69 




52 


60 








+ 6.96 


+13.59 


6.63 




60 


60 








+ 5.06 


- 2.32 




7.38 


58 


60 








- 0.59 


+ 2.70 


3.29 




90 


80 








- 3.62 


+14.72 


18.34 




49 


47 








- 1.58 


+ 0.53 


2.11 




70 


80 


22 


0.19 




- 7.83 


- 0.74 


7.09 




30 


19 




3.00 




+ 0.96 


- 3.08 




4.04 


20 


22 








- 5.51 


+ 0.40 


5.91 




30 


21 








- 4.41 


0.00 


4.41 




16 


16 








- 3.65 


- 6.37 




2.72 


60 


60 








- 0.72 


- 1.54 




0.82 


42 


42 








- 5.92 


- 7.32 




1.40 


76 


60 








- 0.32 


+ 1.45 


1.77 




27 


33 


23 




2.22 


+ 9.72 


+13.50 


3.78 




30 


30 




10.88 




+ 8.92 


+ 6.44 




2.48 


60 


60 








+10.59 


+ 7.87 




2.72 


30 


22 








+ 5.10 


+22.65 


17.56 




63 


60 








+ 0.32 


+11.24 


10.92 




60 


48 








- 1.18 


+ 9.49 


10.67 




38 


29 








+ .5.71 


+16.33 


10.62 




60 


60 








+ 9.96 


+25.12 


16.16 




68 


47 


24 




12.45 


+ 7.19 


+17.86 


10.67 




30 


30 






25.58 


+12.80 


+27.01 


14.21 




30 


30 








+ 2.17 


+12.11 


9.94 




56 


60 








+ 1.77 


+17.73 


15.96 




30 


30 








- 2.03 


+ 4.36 


6.39 




60 


60 








- 7.02 


0.00 


7.02 




60 


60 








-11.80 


- 6.37 


5.43 




60 


60 








- 7.08 


- 5.66 


1.42 




60 


60 


25 




8.34 


+13.49 


+ 6.32 




8.17 


30 


30 






10.09 


- 5.51 


+ 6.66 


12.07 




30 


21 



416 



D WIGHT E. MINNICH 



XI. APPENDIX (TABLE 2)— Continued 



A 


B 


c 


D 


E 


F 


(i 


H 


i 


NUMBER 
OF BEE 


NOBMAL 
BEE AV.° 
PER CM. 
TO RIGHT 
957 MO. 
LIGHT 


NORMAL 
BEE AV." 
PER CM. 
TO LEFT 
957 MC. 
LIGHT 


ONE EYE 
BLACK AV.° 

PER CM. 
TURNED 24 

MO. LIGHT 


ONE ETE 
BLACK AV.° + VALUES 
PER CM. OP E — D 
TURNED 957 OK d 
MC. LIGHT 


— VALUES 

OFE — D 

OHd 


DURATION 
OP REC- 
ORDS TN 
SECONDS 
24 MO. 
LIGHT 


DURATION 

OF REC- 
ORDS IN 
SECONDS 
957 MO. 
LIGHT 


25 






+ 1.63 


- 7.24 




8.87 


22 


28 








- 9.75 


- 3.76 


5.99 




60 


55 








- 2.81 


- 6.57 




3.76 


60 


70 








- 7.27 


- 3.25 


4.02 




30 


30 








- 6.90 


- 6.63 


0.27 




60 


70 








- 3.68 


No reac- 
tion 






36 




31 


5.05 




- 7.14 


- 3.87 


3.27 




63 


48 




5.04 




0.00 


+ 3.02 


3.02 




60 


45 








+ 3.53 


-1- 1.05 




2.48 


71 


74 








- 3.35 


+ 1.73 


5.08 




37 


45 


32 


9.34 




-13.71 


-12.92 


0.79 




60 


60 




12.55 




- 9.22 


-13.28 




4.06 


30 


30 








-12.17 


- 8.86 


3.31 




60 


60 








-14.12 


- 8.85 


5.27 




60 


60 


33 


5.31 




+ 1.92 


- 1.80 




3.72 


78 


70 






8.59 


+ 6.08 


+ 7.25 


2.17 




60 


64 








- 2.12 


+ 5.08 


7.20 




58 


68 








- 6.89 


+ 1.50 


8.39 




33 


29 


34 


2.34 




-19.36 


-21.92 




2.56 


60 


60 




7.66 




-24.85 


-16.82 


8.03 




50 


60 








-18.49 


-16.84 


1.65 




60 


60 








-22.05 


-23.68 




1.63 


60 


60 


36 




0.79 


+ 3.08 


+ 6.29 


3.21 




90 


90 




1.94 




0.00 


+11.35 


11.35 




30 


35 








+ 2.04 


+ 8.85 


6.81 




66 


70 








- 0.66 


+ 2.05 


2.71 




68 


79 


41 


3.92 




+ 6.46 


+ 5.48 




0.98 


62 


60 






0.51 


+ 9.77 


+12.34 


2.57 




66 


67 








- 2.41 


+ 4.63 


7.04 




49 


49 








+ 7.53 


+ 7.30 




0.23 


76 


69 


42 


0.92 




+ 6.01 


+12.24 


6.23 




76 


70 






5.66 + 4.21 


+13.32 


9.11 




57 


60 



PHOTIC REACTIONS OF HONEY-BEE 



417 



XI. APPENDIX (TABLE 2)~Continued 



A 


B 





D 


m 


,.. 


G 


H 


I 


NUMBER 
OF BEE 


NORMAL 
BEE AV.*" 
PER CM. 
IN RIGHT 

957 MC. 

LIGHT 


NORMAL 

BEE AV.° 
PER CM. 
TO LEFT 
957 MC. 
LIGHT 


ONE EYE 
BLACK AV.* 

PER CM. 
TURNED 24 

MC. LIGHT 


ONE EYE 
BLACK AV." 

PER CM. 

TURNED 957 

MC. LIGHT 


+ VALUES 

OFE — D 

OHd 


— VALUES 

OPE — D 

ORd 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
24 MC. 
LIGHT 


DURATION 
OP REC- 
ORDS IN 

SECONDS 
967 MO. 
LIGHT 


42 






+ 8.71 


+11.20 


2.49 




90 


91 








+ 8.45 


+10.47 


2.02 




88 


90 








+ 9.49 


+12.47 


2.98 




60 


60 








+ 7.73 


+18.95 


11.22 




57 


60 








+ 9.03 


+13.70 


4.67 




86 


90 








+11.18 


+10.23 




0.96 


90 


90 








+ 9.34 


+13.48 


4.14 




90 


90 


43 


2.05 




- 9.99 


- 2.55 


7.44 




60 


57 




3.17 




- 4.44 


-12.61 




8.17 


76 


90 








- 8.48 


- 8.43 


0.05 




90 


106 








- 9.57 


-11.06 




1.49 


70 


60 


44 


0.00 




+ 2.04 


+16.10 


14.06 




61 


76 






0.57 


+ 1.43 


+13.73 


12.30 




60 


46 








+ 4.53 


+10.36 


6.83 




73 


70 








+ 2.05 


+ 8.76 


6.71 




72 


70 


45 


5.20 




+ 1.97 


+ 2.39 


0.42 




48 


60 




8.01 




+ 1.03 
No rec- 
ord 


+ 3.80 
-11.17 


2.77 




62 


69 
84 








- 4.68 


- 8.76 




4.08 


69 


60 


51 




3.41 


- 4.49 


+ 1.43 


5.92 




60 


63 






3.75 


- 3.96 


- 0.44 


3.52 




42 


48 








+ 2.87 


+ 5.05 


2.18 




60 


65 








- 8.30 


- 5.05 


3.25 




71 


70 


52 




5.00 


+ 6.22 


+ 9.06 


2.84 




91 


99 




2.35 




+ 2.37 


+ 4.59 


2.22 




66 


74 








+ 3.30 


+ 5.02 


1.72 




97 


111 








+ 8.44 


+ 7.67- 




0.87 


75 


76 








+ 6.94 


+11.07 


4.13 




71 


78 


53 




2.08 


- 5.65 


- 3.41 


2.24 




59 


65 






2.61 


- 9.92 


- 3.79 


6.13 




73 


59 








- 1.19 


- 6.19 




5.00 


65 


50 








- 9.72 


- 3.63 


6.09 




30 


32 


64 


6.91 




- 0.79 


+ 8.23 


9.02 




85 


90 



'418 



D WIGHT E. MINNICH 



XI. APPENDIX (TABLE 2)— Continued 



A 


B 





D 


E 


F 


Q 


H 


I 


NUMBER 
OF BEE 


NOBMAJi 
BEE AV.° 

FEB CM. 
TO BIGHT 

957 MC. 
■ LIGHT 


NOBMAL ■ 
BEE AT." 
FEB CM. 
TO LEFT 
967 MC. 
LIGHT 


ONE EYE 
BLACK AV.° 

FEB CM. 
TURNED 24 
MC. LIGHT 


ONE EYE 

BLACK AV.° 

FEB CM. 

TURNED 957 

MC. LIGHT 


+ VALUES 

OFE — D 

OBd 


— VALUES 

OPE — D 

OBd 


DURATION 

OFREO- 

0B08 IN 

SECONDS 

24 MO. 

LIGHT 


DURATION 
OF REC- 
ORDS IN 

SECONDS 

957 MO. 

LIGHT 


54 


3.11 




+. 5.77 


+ 8.25 


2.48 




51 


59 








+ 8.20 


+ 6.63 




1.57 


50 


31 








+ 3.37 


+ 3.54 


0.17 




76 


67 








+ 1.70 


+ 3.71 


2.01 




112 


105 


55 




7.69 


- 0.35 


+ 4.36 


4.71 




66 


55 






4.17 


+ 8.14 


+ 8.89 


0.75 




72 


64 








+ 9.88 


+ 7.89 




1.99 


84 


119 








+ 8.64 


+ 6.78 




1.86 


80 


76 


56 




0.32 


+ 1.50 


-12.86 




14.36 


61 


64 






1.45 


+ 1.14 


-10.27 




11.41 


35 


30 








- 3.73 


+ 1.83 


5.56 




73 


69 








-10.56 


-18.47 




7.91 


100 


115 


62 


1.38 




+ 1.55 


+ 1.36 




0.19 


83 


73 






2.05 


+ 4.54 


+ 2.98 




1.56 


133 


122 








+ 1.88 


+ 9.18 


7.30 




98 


99 








+ 4.42 


+ 8.71 


4.29 




84 


80 








+10.73 


+11.61 


0.88 




77 


63 








+ 6.05 


+ 6.33 


0.28 




110 


110 








+ 5.79 


+10.79 


5.00 




42 


40 








+ 5.58 


+ 5.87 


0.29 




112 


113 








+ 7.59 


+ 7.45 




0.14 


116 


120 








+ 4.50 


+ 4.47 




0.03 


103 


99 


63 




5.58 


+ 0.48 


+11.83 


11.35 




52 


49 




7.50 




+ 3.94 


+ 8.56 


4.62 




78 


72 








+11.64 


+ 2.61 




9.03 


35 


38 








+10.69 


+ 8.45 




2.24 


48 


50 








+ 4.13 


+ 4.50 


0.37 




87 


74 








+ 3.04 


+ 3.41 


. 0.37 




48 


61 








+ 3.59 


+12.00 


8.41 




41 


30 








+ 0.18 


+ 8.74 


8.56 




56 


60 








+ 2.99 


+ 9.21 


6.22 




50 


48 








+ 7.00 


+ 9.87 


2.87 




46 


50 








+12.58 


+14.74 


2.16 




60 


54 








+ 5.59 


+ 7.79 


2.20 




80 


85 


66 




1.82 


+ 6.78 


+ 6.48 




0.30 


46 


46 



PHOTIC REACTIONS OF HONEY-BEE 



419 



XI. APPENDIX (TABLE 2)~Continued 



A 


B 





B 


n 


p 


G 


H 


I 


NITMBEB 
OP BEE 


NOBMAL 

BEE AV.° 
FEB CM. 

TO BIQHT 
957 MC. 
LIGHT 


HOBMAL 
BEE AV.° 

FEB CM. 
TO LEFT 

957 MC. 
LIGHT 


ONE ETE 
BLACK AV.° 

FEB CM. 
TnBNED 24 
MC. LIGHT 


ONE ETE 
BLACK AV.° 

FEB CM. 

TUBNED 05^ 

MO. LIGHT 


+ VALUES 

OPE — D 

OBd 


~ VALUES 

OFB — D 

OBd 


DUBATION 

OPKEC- 

OBDS IN 

SECONDS 

24 MC. 

LIGHT 


DUBATION 
OP BBO- 
OBDS IN 

SECONDS 
957 MO. 
LIGHT 


66 




0.18 


+ 6.46 


+ 4.07 




2.39 


85 


93 








+ 1.73 


+ 4.27 


2.54 




68 


68 








+ 4.36 


+ 8.27 


3.91 




64 


55 








+ 7.40 


+ 8.68 


1.28 




96 


86 








+ 9.45 


+ 5.87 




3.58 


60 


60 








+ 5.23 


+ 4.93 




0.30 


142 


136 








+ 4.98 


+ 4.60 




0.38 


ioo 


104 








+ 3.02 


+11.09 


8.07 




83 


80 








+ 5.59 


+10.32 


4.73 




101 


122 


68 


6.08 




+ 4.35 


+13.12 


8.77 




97 


94 




1.94 




+11.65 


+16.40 


4.75 




66 


67 








+ 5.56 


+14.91 


9.35 




54 


59 








+ 8.97 


+11.23 


2.26 




60 


69 








+ 8.83 


+ 9.82 


0.99 




87 


100 








+10.57 


+12.21 


1.64 




53 


63 








+ 5.62 


+12.06 


6.44 




75 


60 








+10.48 


+13.52 


3.04 




75 


87 








+ 5.32 


+11.79 


6.47 




91 


99 








+ 4.37 


+ 4.76 


0.39 




100 


104 


72 


5.73 




+ 7.13 


+ 9.11 


1.98 




60 


60 




7.30 




+ 1.02 


+24.35 


23.33 




20 


35 








+ 2.65 


- 0.29- 




2.94 


77 


58 








+ 0.87 


+ 3.13 


2.26 




87 


86 








- S.92 


- 0.66 


3.26 




103 


100 








+ 6.77 


+ 6.22 




0.55 


120 


120 








+10.17 


+12.94 


2.77 




100 


91 


73 




4.94 


'+ 0.92 


+ 8.27 


7.35 




39 


40 






2.24 


+ 1.53 


+ 4.22 


2.69 




34 


34 








- 1.42. 


+13.04 


14.46 




60 


65 








+ 2.45 


+10.89 


8.44 




100 


100 








+ 2.00 


+12.55 


10.55 




61 


75 








+ 3.29 


+13.79 


10.50 




93 


101 








+ 2.88 


+ 9.49 


6.61 




104 


87 








- 0.12 


- 8.89 


9.01 




147 


147 








+ 6.07 


+13.82 


7.75 




135 


136 








- 1.69 +15.55 


17.24 




110 


110 



420 



DWIGHT E. MINNICH 



XI. APPENDIX (TABLE 2)— Continued 



A. 


B 





D 


E 


F 


G 


H 


I 


NUMBER 
OF BEE 


NORMAL 
BEE AV.° 

PEBCM. 
TO RIGHT 

957 MC. 
LIGHT 


NORMAL 
BEE AV.° 

PER CM. 
TO LEFT 

957 MO. 
LIGHT 


ONE EYE 
BLACK 'AV.° 

PER CM. 
TURNED 24 
MC. LIGHT 


ONE EYE 
BLACK AV." 

PER CM. 
TURNED 957 

MC. LIGHT 


+ VALUES 
OF E — D 

or d 


— VALUES 

OF E — D 

OR d 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
24 MO. 
LIGHT 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
957 MO. 
LIGHT 


77 


4.22 




+10.71 


+14.43 


3.72 




57 


~75 




7.46 




+ 9.62 


+16.59 


6.97 




88 


65 








+13.53 


+18.39 


4.86 




48 


40 








+12.43 


+14.74 


2.31 




104 


80 








+ 8.45 


+14.92 


6.47 




90 


80 








+11.64 


+16.89 


5.25 




120 


130 








+12.60 


+15.38 


2.78 




,75 


70 








+15.29 


+17.98 


2.69 




40 


35 








+11.57 


+18.36 


6.79 




80 


80 


81 


2.09 




+ 4,21 


+10.60 


6.39 




114 


117 




2.59 




+ 1.03 


+ 3.98 


2.95 




53 


53 








+ 6.03 


+ 7.78 


1.75 




116 


106 








+ 5.76 


+ 5.86 


0.10 




108 


101 








+ 3.30 


+ 8.35 


5.05 




70 


65 








+ 4.59 


+ .9.89 


5.30 




56 


61 








+ 5.03 


+ 7.49 


2.46 




63 


63 








+ 4.81 


+13.52 


8.71 




57 


80 








+ 2.76 


+ 8.21 


5.45 




110 


122 








+ 3.71 


+12.60 


8.89 




67 


67 


82 




5.81 


- 3.94 


- 2.33 


1.61 




124 


119 






0.65 


- 5.37 


- 5.01 


0.36 




110 


123 








-10.30 


- 6.43 


3.87 




60 


60 








- 6.95 


- 4.88 


2.07 




59 


69 








- 2.59 


+ 1.42 


4.01 




66 


64 








- 3.29 


- 0.57 


2.72 




74 


85 








- 7.06 


+ 2.46 


9.52 




54 


56 








- 6.40 


- 5.29 


1.11 




70 


80 








- 0.80 


- 5.47 




4.67 


108 


106 


83 


3.59 




+ 5.62 


+15.93 


10.31 




81 


76 




5.85 




+ 8.37 


+15.73 


7.36 




90 


90 








+ 8.89 


+10.53 


1.64 




104 


104 








+ 6.93 


+11.49 


4.66 




71 


71 








+12.84 


+21.53 


8.69 




58 


60 








+ 9.39 


+17.47 


8.08 




60 


60 








+ 4.93 


+16.39 


11.46 




94 


90 








+ 4.53 


+12.50 


7.97 




41 


33 








+ 3.52 


+14.42 


10.90 




133 


128 



PHOTIC REACTIONS OP HONEY-BEE 



421 







XI. APPENDIX (TABLE 2)— Continued 






a 


B 





T\ 


B 


p 


u 


H 


I 


NUMBER 
OF BEE 


NORMAL 

BEE AV.* 

PEE CM. 

TO SIGHT 

957 MO. 

LIGHT 


NORMAL 
BEE AV." 

PER CM. 
TO LEFT 

957 MC. 
LIGHT 


ONE EYE 
BLACK AV.° 

PER CM. 
TURNED 24 
MO. LIGHT 


ONE ETE 
BLACK AV." 

PER CM. 
TURNED 957 

MO. LIGHT 


■+• VALUES 

OF B — D 

ORd 


— VALUES 

OR B — D 

ORd 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
24 MC. 
LIGHT 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
957 MO. 
LIGHT 


85 




0.84 


+ 6.46 


+12.52 


6.06 




47 


46 






0.93 


+ 1.41 


+ 7.78 


6.37 




113 


117 








+ 7.08 


+ 3.74 




3.34 


75 


82 








+ 6.87 


+ 6.42 




0.45 


80 


108 








+ 4.34 


+ 3.54 




0.80 


126 


123 








+ 1.73 


+ 3.63 


1.90 




64 


74 








+ 4.61 


+ 8.19 


3.58 




137 


123 








+ 6.13 


+ 7.45 


1,.32 




94 


94 








+ 4.68 


+ 7.99 


3.31 




71 


58 


91 


0.48 




- 2.42 


- 4.98 




2.56 


125 


125 




6.99 




-10.05 


- 4.00 


6.05 




85 


80 








- 6.44 


- 6.05 


0.39 




95 


95 








- 7.33 


- 3.05 


4.28 




81 


81 








+ 2.18 


+ 3.52 


1.34 




110 


131 








+ 0.73 


+ 6.69 


5.96 




64 


64 








+10.19 


+27.54 


17.35 




30 


30 


92 




10.66 


+ 4.42 


+ 5.77 


1.35 




113 


104 




( 


8.67 


+ 4.28 


+ 9.86 


5.58 




58 


62 








+ 7.41 


+ 9.19 


1.78 




94 


85 








+ 9.64 


+ 7.64 




2.00 


63 


61 








+ 7.49 


+17.34 


9.85 




52 


52 








+14.19 


+23.82 


9.63 




60 


60 


93 




0.21 


+ 1.61 


+ 6.48 


4.87 




120 


120 




2.44 




+ 0.19 


+ 1.42 


1.23 




99 


99 








+ 2.87 


- 0.46 




3.33 


63 


63 








+ 2.37 


+ 2.92 


0.55 




98 


87 


95 




2.29 


+ 2.14 


+ 4.89 


2.75 




118 


123 






6.62 


+ 1.13 


+ 3.07 


1.94 




100 


109 








0.00 


+ 5.67 


5.67 




68 


46 








+ 0.32 


+ 6.58 


6.26 




71 


80 








+ 1.29 


+ 4.82 


3.53 




70 


78 








+ 0.93 


+11.94 


11.01 




34 


30 








+ 2.39 


+ 7.18 


4.79 




69 


74 








+ 3.67 


+ 7.11 


3.44 




66 


67 








+ 0.85 


+ 6.35 


5.50 




82 


76 








+ 0.21 


+ 1.93 


1.72 




61 


60 



THE JOURNAL OF BXPEBIMBNTAL ZObLOOT, VOL. 29, NO. 3 



422 



DWIGHT E. MINNICH 



XI. APPENDIX (TABLE 2)— Continued 



A 


B 





D 


E 


F 


o 


H 


I 


NUMBER 
OF BEE 


HOBMAL 
BEE AV.° 

FEB CM. 
TO BIGHT 

957 MO. 
LIOHT 


NOBMAL 
BEE AT.° 
FEB CM. 
TO LEFT 

957 MO. 

LIQHT 


ONE ETE 
BLACK AV.° 

FEB CM. 
TURNED 24 
MC. LIGHT 


ONE EYE 
BLACK AV.° 

FEB CM. 

TURNED 957 

MC. LIGHT 


+ VALUES 

OFE — D 

OBd 


— VALUES 

OFE — D 

OR d 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
21 MC. 
LIGHT 


DURATION 
OP REC- 
ORDS IN 
SECONDS 

957 MO. 

LIGHT 


96 




2.76 


+10.46 


+19.08 


8.62 




90 


92 




5.54 




+ 9.29 


+ 8.50 




0.79 


195 


192 








+11.89 


+15.99 


4.10 




60 


60 








+14.09 


+ 17.84 


3.75 




60 


60 








+ 5.33 


+10.15 


4.82 




35 


29 


101 




7.11 


- 5.47 


- 2.55 


2.92 




62 


63 






6.10 


- 1.67 


- 2.07 




0.40 


88 


79 








- 2.09 


- 0.61 


1.48 




60 


59 








- 1.02 


- 1.00 


0.02 




67 


70 ■ 








- 3.34 


- 1.58 


1.76 




46 


49 


102 


3.67 




- 1.58 


+14.37 


15.95 




49 


49 




5.30 




+ 2.98 


+15.02 


12.04 




50 


54 








+ 3.75 


+11.08 


7.33 




71 


78 








- 2.23 


+ 1.45 


3.68 




62 


66 








- 0.32 


+ 6.46 


6.78 




64 


53 








- 3.38 


+11.11 


14.49 




57 


58 








- 1.98 


+ 4.52 


6.50 




41 


60 








- 2.23 


+10.19 


12.42 




88 


88 








+ 3.55 


+13.35 


9.80 




95 


95 








- 1.28 


+12.23 


13.61 




70 


60 


103 


0.00 




- 2.46 


+13.48 


15.94 




57 


57 




6.34 




- 4.29 


+11.25 


15.54 




77 


60 








+ 0.16 


+ 8.49 


8.33 




60 


69 








- 1.26 


+11.36 


12.62 




61 


61 








- 0.44 


+ 2,15 


2.59 




84 


84 








- 3.75 


+11.04 


14.79 




60 


60 








+ 3.89 


+ 6.47 


2.58 




60 


65 








+ 2.27 


+ 6.99 


4.72 




63 


68 








- 0.18 


+ 0.22 


0.40 




105 


104 








+ 0.86 


+ 4.22 


3.36 




62 


64 


105 


5.93 




+ 8.46 


+14.64 


6.18 




68 


60 




8.81 




'+ 9.19 


+13.78 


4.59 




50 


60 








+ 6.89 


+14.10 


7.21 




80 


80 








+ 6.55 


+15.20 


8.65 




60 


60 








+ 6.74 


+14.83 


8.09 




93. 


93 








+ 6.21 


+12.73 


6.52 




60 


60 








+10.34 


+16.05 


5.71 




60 


60 



PHOTIC EEACTION8 OF HONEY-BEE 



423 







XI. APPENDIX (TABT.F, 2)~Continued 






A 


B 


a 


D 


E 


F 


a 


H 


I 


NUMBER 
OF BEE 


NORMAL 

BEE AV.° 

PER CM. 

TO RIGHT 

957 MO. 

LIGHT 


NORMAL 
BEE AV.° 
PER CM. 
TO LEFT 

957 MO. 

LIGHT 


ONE ETB 
BLACK AV.° 

PER CM. 
TURNED 24 

MC. LIGHT 


ONE EYE 

BLACK AV.° 

PER CM. . 

TURNED 957 

MC. LIGHT 


+ VALUES 

OPE — D 

ORd 


— VALUES 

OF E — D 

ORd 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
24 MC. 
LIGHT 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
957 MC. 
LIGHT 


105 






-(-10.03 


4-17.05 


7.02 




60 


60 








-1- 9.04 


4-11.01 


1.97 




100 


100 








-1- 7.46 


4-12.68 


5.22 




163 


163 


106 


6.43 




- 1.18 


4- 1.49 


2.67 




70 


68 




1.71 




-1- 0.44 


4- 3.22 


2.78 




81 


79 








+ 2.79 


4- 6.72 


3.93 




41 


41 








- 1.49 


4- 5.19 


6.68 




36 


35 








+ 0.59 


- 5.49 


4.90 




77 


77 








+ 0.53 


4- 5.33 


4.80 




103 


115 


121 


1.61 




+ 2.96 


4-24.04 


21.08 




60 


60 






6.87 


4-11.57 


4-19.71 


8.14 




60 


60 








-f 3.13 


4-15.11 


11.98 




92 


88 








+ 1.91 


4-12.12 


10.21 




87 


91 








- 4.71 


4-17.50 


22.21 




60 


60 


122 


2.31 




+ 1.88 


4- 8.96 


7.08 




69 


73 




2.93 




-t- 3.65 


4- 3.77 


0.12 




118 


111 




t 




-1- 3.25 


4- 1.99 




1.26 


90 


85 








- 4.39 


4- 6.50 


10.89 




56 


65 


123 




17.86 


-1- 7.16 


4-18.55 


11.39 




54 


60 






3.60 


+ 1.79 


- 1.21 




4.00 


66 


69 








-10.76 


4- 0.59 


11.35 




69 


67 








- 8.08 


4- 2.29 


10.37 




79 


79 








- 7.61 


- 2.14 


5.47 




60 


60 








- 3.46 


4- 1.12 


4.58 




140 


135 








- 3.25 


4- 5.69 


8.94 




60 


58 








- 3.53 


4- 0.56 


4.09 




58 


68 








- 2.21 


4- 1.97 


4.18 




90 


101 


124 




2.59 


-1- 3.88 


4-11.18 


7.30 




73 


68 






3.00 


+ 3.94 


4- 6.45 


2.61 




53 


59 








-1- 2.54 


4- 8.38 


6.84 




79 


71 








4-10.36 


4-11.19 


0.83 




80 


80 








-1-11.04 


4-17.61 


. 6.57 




90 


90 








+ 10.39 


4-17.41 


7.02 




60 


60 








+ 5.81 


4-12.54 


6.73 




58 


58 








4- 6.55 


4- 8.95 


2.40 




74 


60 








4- 7.67 


4-10.19 


2.52 




60 


60 



424 



DWIGHT E. MINNICH 



XI. APPENDIX (TABLE 2)~Continued 



A 


B 


c 


D 


E 


F 


o 


H 


I 


NUMBER 
OF BEE 


NOBUAL 

BEE AT.° 
FEB CM. 

TO BIGHT 
957 MC. 
LIGHT 


NORMAL 

BEE AV." 
PER CM. 
TO LEFT 

957 MC. 

LIGHT 


ONE ETE 

BLACK AV." 

PER CM. 
TURNED 24 
MC. LIGHT 


ONE ETE 
BLACK AV.° 

PEE CM. 

TUBNED 96' 

MC. LIGHT 


+ VALUES 
OFE — D 
f OB d 


— VALUES 

OFE — D 

OBd 


DUKATION 

OF EEC- 

OBDS IN 

SECONDS 

24 MC. 

LIGHT 


DURATION 
OF REC- 
ORDS IN 
BECONDS 
957 MC. 
LIGHT 


126 




6. 51 


- 1.39 


+ 3.11 


4.50 




105 


100 






1.19 


+ 4.51 


- 2.89 




7.40 


48 


60 








+ 3.73 


+ 6.14 


2.41 




78 


77 








- 1.44 


•+23.37 


24.81 




45 


46 








+ 1.83 


+ 4.41 


2.58 




107 


107 








+ 4.57 


+ 3.65 




0.92 


148 


153 








+ 5.51 


+ 4.32 




1.19 


72 


72 








- 2.98 


- 2.26 


0.72 




83 


83 








- 1.49 


+ 3.73 


5.22 




25 


28 


133 


2.82 




+ 2.39 


+ 3.18 


0.79 




70 


74 




5.86 




+ 1.98 


+ 3.26 


1.28 




69 


68 








+ 1.54 


+ 4.31 


2.77 




60 


61 








+ 4.79 


+ 9.29 


4.50 




60 


60 








+ 1.76 


+ 4:92 


3.16 




82 


76 








+ 3.30 


+11.54 


8.24 




38 


40 








+ 3.35 


■+ 7.77 


4.42 




64 


68 


134 




1.52 


+ 8.29 


+19.62 


11.33 




69 


69 






1.22 


+ 9.94 


+19.60 


9.66 




57 


67 








+ 5.67 


+18.19 


12.52 




80 


80 








+ 0.22 


+18.93 


18.71 




60 


60 








+ 3.83 


+12.53 


8.70 




58 


58 


136 




10.77 


- 3.25 


- 0.54 


2.71 




63 


61 






10.88 


+ 0.74 


+ 2.03 


1.29 




95 


89 








+ 1.29 


+ 3.35 


2.06 




109 


109 








- 9.49 


- 5.85 


3.64 




58 


59 








+ 2.28 


- 1.37 




4.65 


71 


71 








- 1.05 


- 3.03 




1.98 


94 


94 








- 0.33 


- 7.67 




7.34 


79 


76 








+ 0.44 


- 6.66 




7.10 


58 


59 


137 




5.99 


+11.73 


+19.09 


17.36 




60 


60 






2.94 


+15.82 


+16.09 


0.27 




49 


49 








+10.59 


+16.45 


5.86 




70 


70 






^ 


+15.78 


+16.57 


0.79 




60 


60 








+14.31 


+15.40 


1.09 




78 


78 








+14.71 


+22.57 


7.86 




60 


60 








+14.69 


+17.02 


2.33 




70 


70 



PHOTIC REACTIONS OF HONEY-BEE 



425 



XI. APPENDIX (TABLE 2)— Concluded 



A 


B 


C 


D 


E 


F 


G 


H 


I 


NUMBER 
OF BEE 


NOBMAL 
BEE AV.* 
PER CM. 
TO RIGHT 
957 MC. 
LIGHT 


NORMAL 
BEE AV." 
PEB CM. 
TO LEFT 
957 MO. 
LIGHT 


ONE ETE 
BLACK AV.* 

PEB CM. 
TURNED 24 
MC. LIGHT 


ONE EYE 
BLACK AV." 

PER CM. 

TURNED 957 

MC. LIGHT 


4* VALUES 

OF E— D 

OBd 


— VALUES 

OFE - D 

OBd 


DURATION 
OF REC- 
ORDS IN 
SECONDS 
24 MO. 
LIGHT 


DUBATION 

OPREC- 

OBDB IN 

SECONDS 

957 MC. 

LIGHT 


137 






+13.38 


+ 15.64 


2.26 




60 


60 








+ 8.43 


+ 16.71 


8.28 




60 


BO 








+15.92 


+18.08 


2.16 




60 


60 


138 




6.55 


- 0.18 


- 4.67 




4.49 


129 


129 






8.37 


- 0.37 


+ 0.13 


0.50 




62 


58 








- 1.12 


+13.52 


14.64 




65 


60 








- 9.00 


- 3.52 


5.48 




70 


70 








- 3.07 


+ 1.60 


4.67 




115 


115 








- 1.97 


+ 2.57 


4.54 




77 


74 








- 6.19 


- 1.08 


5.11 




69 


69 



CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF 
THE MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD 
COLLEGE. {Continued.) 



E. L. Mark, Director. 

*«• Abbreviations used : — 

B.M.G.Z for Bull. MU9. Comp. ZoSI. 

P. A. A for Proceed. Amer. Acad. Arts and Sci. 

P.B.S.N.H for Proceed. Bost. Soc. Nat. Hist. 

Note. — Copies of the List of Oontributiona, ^Humbert 1-278, will be 
aent on applicatton. 

277. Wbnhioh, D.H. — Notes on the Reactions of Bivalve Mollusks to Changes in 

Light Intensity : Image Formation in Pecten. Jour. Anim. Behavior, 6 (4) : 
297-318. July-Aug-, 1916. 

278. AnsT, L. B. — The Influence of Liglit and Temperature upoi; the Migration oi 

the Betinal Pigment of Planorbis trivolvis. Jour. Comp. Neurol., 36 (4) :369- 
889, 1 pi. Aug., 1916. 

279. Wai/tok, a. C. — Reactions of Paramoecium caudatum to Light. Jour. Anim. 

Behavior, 6 (5) : 336-340. Sept.-Oct., 1916. 

280. Walton, A. C. — The ' Refractive Body ' and the * Mitochondria ' of Ascaris 

canis Werner. Proc. Amer. Acad. Arts and Sci., S3 (5) : 253-266, 2 pis. Oct., 
1918. 

281. Pabkek, Gr. H., and Titus, E. G. — The Structure of Metridium (Actinoloba 

marginatus Milne-Edwards vrith' Special Reference to its Neuro-muscular 
Mechanism. Jour. Exp. Zool., 31 (4): 438-459, 1 pi. Nov., 1916. 

282. Parker, G. H. — The Elector Systems of Actinians. Jour. Exp. Zool., 31 (4) : 

461-484. Nov., 1916. 

283. Walton, A. C. — A Case of the Occurrence of Ascaris triquetraSchrankinDogs. 

Jour. Parasitol., 3 (1) : 39-41. Sept. [Nov.], 1916. 

284. Parker, G. H. — Nervous Transmission in the Actinians. Jour. Exp. ZoQI., 33 

(l):B7-94. Jan., 1917. 

285. Parker, G. H. — The Movements of the Tentacles in Actinians. Jour. Exp 

ZoBb, 23 (1): 95-110. Jan., 1917. 

286. Parker, 6. H. — Pedal Locomotion in Actinians. Jour. Exp. Zool., 33 (1) : 111- 

124. Jan., 1917. 

287. Parker, G. H. — The Responses of Hydroids to Gravity. Proc. Nat. Acad. Sci., 

3 (2) : 72-73. Feb., 1917. 

288. Cole, W. H. — The Reactions of Drosophila ampelophila Loew to Gravity, Cen- 

trifugation, and Air Currents. ■ Jour. Ahim. Behavior, 7 (1) ; 71-80. Jan., 1917. 

289. Olmsted, J. M. D. — Geotropism in Flanaria maculata. , ^Jour. Anim. Behayior, 

r (1): 81-86. Jan. 1917. 

290. Parker, G. H. — Actinian Behavior. Jour. Exp.' ZoHl., 23 (2) : 193-229. Feb., 

1917. 

291. REDFiBLDfE.S. P. — The Rhythmic Contractions of the Mantle of Lamellibranchs. 

Jour. Exp. Zool., 22 (2) : 231-239. Feb., 1917. 

292. Redfield, a. C. — The Reactions of the Melanophorcs of the Horned Toad. 

Proc. Nat. Acad. Sci., S (3) : 202-203. Mar., 1917. 

293. Redfield, a. C. ^The Cobrdination of the Melanophore Reactions of the Horned 

Toad. Proc. Nat. Acad. Sci., 3 (3) : 204-206. Mar., 1917. 

294. Pope, P. H. — The Introduction of West Indian Anura into Bermuda. Bull. Mus. 

Comp. Zool., 61 (6) ai7-13i,l2 pis. May, 1917. 

295. Van Heusen, A. P. — The Skin of the Catfish { Amiorus nebulosus) as a Re- 

ceptive Organ for Light. Amer. Jour. Physipl., 44 (2) : 212-214. Sept., 1917. 

296. Parker, G. H., and Van Hbtjsen, A. P. — The Responses of the Catfish, Amlurus 

nebulosus, to Metallic and Non-metallic Rods. Amer. Jour. Physiol., 44 (3) : 
406-420. Oct., 1917. 
297.- Parker, G.H. — The Pedal Locomotion of the Sea-Hare Aplysia californica. 
Jour. Exp. Zool., 24 (1) :l'39-145. Oct., 1917. 

298. Parker, G. H., and Van Heosen, A. P. — The Reception of Mechanical Stimuli 

by the Skin, Lateral-Line Organs and Ears in Fishes, especially in Amlurus. 
Amer. Jour. Physiol., 44 (4) : 463-489. Nov., 1917. 

299. Parker, G. H. — ThePowerofSactionintheSea-AnemoneCribrina. Jour. Exp. 

ZoBL, 34 (2): 219-222. Nov., 1917. 



CONTRIBUTIONS FROM THE ZOOLOGICAL LABORATORY OF 
THE MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD 
COLLEGE. {Continued.) 

300. Parker, G. H. — The Activities of Coi-ymorpha. Jour. Exp. Zool., 24 (2) : SOS- 
SSI. Nov., 1917. 

SOI. Stbinsbb, C. E. — The Mea,nj of Locomotion in Plaoarians. Proc. Nat. Acad. 
Sci., 3 (12) :691-692. Dec, 1917. 

302. Olmsted, .J. M. D. — The Reseneration of Triaagiilar Pieces of Planariamaculata. 
A Staily in Polarity. Jour. Bxp. ZoBl., 85 (1) :157^176. Feb., 1918. 

SOS. ( Hecht, S. —The Physiologj of Ascidia atra Lesueur. I. General Physiology. 

304.1 II. Sensory Physiology. Jour. Exp. ZoBL, 25 (1) ; 229-299. Feb., 1918. 

305. Heoht.S. — Id. III. The Blood System. Amer. Jour. Physiol., 45 (3) : 167-187. 

Feb., 1918. 

306. Brat, A. W. L. — The Reactions of the Melanophores of Amiurus to Light and 

Adrenalin. Proc. Nat. Acad. Sci., 4 (3) : 68-60. Mar., 1918. 

307. Walton, A. C — The Oogenesis and Early Embryology of Ascaris cams Werner. 

Jour. MorDh.,30 (2) : 627-603. Mar., 1918. 

308. Olmsted, J. M. D. — Experiments on the Nature of the Sense of Smell in the 

Common Catfish, Amiurus uebulosus (Lesueur). Amer. Jour. Physiol., '46 
(6):443-468. Aug., 1918. 

309. Bedfield, a. C — The Physiology of the Melanophores ol the Horned Toad, 

Phryhosoma. Jour. Exp. Zool., 26 (2) : 276-333. July, 1918. 

310. Brooks, E. S. — Reactions of Frogs to Heat and Cold, Amer. Jour. Physiol., 

46 (6) :493-601. Aug., 1918. 

311. Cobb, P. H. — Autonomous Responses of the Labial' Palps of Anodonta. Proc. 

Nat. Acad. Sci., 4 (8) : 234-236. Aug., 1918. 

312. Irwin, M.— The Nature of Sensory Stimulation by Salts. Amer. Jour. Physiol., 

47 (2): 265-277. Nov., 1918. 

313. Parker, G. H. — The Rate of Transmission m the Nerve Net of the Coelenterates. 

Jour. Gen. Physiol., 1 (2) : 231-236. Nov., 1918. 

314. BisNBY, A. J. — The Effect of Adrenin on t\\k Pigment Migration in the Melano- 

phores of the Skin and in the Pigment Cells of the Retina of the Frog. Jour. 
Exp. Zool., 3r (3): 391-396. Jan., 1919. 

315. Jordan, H.. — Concerning Reissner's Fiber in Teleosts. Jour. Comp. Neurol., 

.to (2): 217-227, 1 pi. Feb., 1919. 
S16. Pahker.G. H. — The Organization of Renilla. Jour. Exp. Zool., 27 (4):499- 
607. Feb., 1919. 

317. .Hunt, H. R. — Regenerative Phenomena following the Removal of the Digestive 

Tube and the Nerve Cord of Earthworms. Bull. Mus. Comp. Zool., 63 (16): 
569-681, 1 pi. Apr., 1919. 

318. Davis, D. W. — Asexual Multiplication and Regeneration in Sagartia luciae 

Verrill. Jour. Exp. Zool., 28 (2): 161-204. May, 1919. 

319. Parker, G. H. — The Effects of the past Winter on the Occurrence of Sagartia 

luciae Verrill. Amer. Nat., 5S (626): 280-281. May-June, 1919. 

320. MiNNicH, D. E. — The Photic Reactions of the Honey-Bee, Apis mellifera L. 

Jour. Exp. Zool , 2» (3) : 343-425. Nov., 1919. 



C!«S'rR|BUTiplS& S!«0* THE ZOdxOGlCAl. LASOiBATORY OJf 
V; THE M,tI3BUM OF COMI'ABATIVE ZOOLOGY AT HAKVABD 



%' iji M.ATiS.,' JDirtctor, 



^ ^ B.M.C.Z. . . . . for BuU, Mn».' fiorn]). 2S()8K . 'v , 

' j^A.A. .forPro?eetl..Ainej'. AciB. AttB»8i}8ch~ 

P,B.8.N.rH., ........ .for ift-o6eti4,Bort.!STO.N»l.]3iBt, -■•- 

i!mra.^ Copiti of the Utro/O^ntrilmliona/MfAberii 1-376, toiU.be 
'• .^erftmn applicatiim, . 

: 377: 'SirKSiapB; D. U.— kbtesion tUeBe&ctiijiis of ,BiTttlTi-fl:|ft>iJn9lss to Cl)aiige»'i in 
hi^iti latooMyi loiiikge Formati<j8-in Pestefl.! , Jaur.,An>iitBehaViorf« (4) : 
'- ,- 297-318. .Jiiiy.:ABgi. 19l6. -• -^^ ''' : ,. <', '_ 

3jra. Akby^jIi. B,~ The Inttuen4e of Light a«d Tem^Sratare upon tlli Miration oi 
r-fr';' >:r-tiiiie fietkal 'Bi^tnent of HtaorijtsitriT^ylvis. JoWr. CoWp. Neiiroi., S^O (4) ;S59» 
^., ,■ -J' -389,1 pLu; Aug,, 1916. \. , ;;'^ , „:: ,V i:"- ' ", ' \ ■-■-■'--/"■''■ 

' SJSi Wai/tos, a. C— Reactions Sf Pal^mbeciilja eaudatum to Light. Joiir. Anim. ' 

,^"' fshftvtor, 6 (6),: 385-84*1. f3,cpt,-Oqt./l916, - , V i ■ '■ - '■ - - ' "• 

&0. : iVAiieu.A.C.^The 'Sf,ffaotitB'Bb%'' mid the f^ilio^btoijrik,' , of Ascsrii 

:' .cania 'Vyeraer.^ Ptoo.j^et. Aoad. Arts ^ftid Sci:, S^ (6) : 253-266,2 pis. Oct^, 

'' , ]' JSie: ' ; \f~. V, ,oi., - ,, ' i\ ■''[ V .■- ■ ' •'-^:''-:-. '/' -^ 

2fc 'PAiiKitB,'ir.HijrfNi)]h^*& oC Meteihata. (Aq!;jjiioI»^i«\ 

-'■^.. ; m^ginatiis Milne-Edwards ,. with Special ReferMfea to its ]S'«t(itb-m«scul»r' 
; MechiinisiSi. Joiir,Bxp.?p81., 81,(4): 438^9,'! pJ.SFoT., 1919.' V-V 

!282.. PAHEpxB.Ci.^.'— ;The:plfleot(S»si^atBhis of Aotinlans., Jour. Exp., 2081.7*1(4): 

,;,i' :,| 48ir4^. ,NorMl916. . ' ' '^'{' [ t .' ■ V ./.- [ V, ■■""'- "', 
S83. ^siSjoSi A. C.-f A^asjo of the pccari'oufce of Ascario triciuc^tr^SclirimkipDogt. 
,, •Toaii.Jj'ataaitol., ."8 (1):8»^1, ,,Sept. [NoT.],19ia. .;''-: , , 

2S4..- Pabhss, Gr. H. — I^crrous 'CraQsmission ib th^ Actinians^ , Jour.tExp. ZobLyliil 

-• - (l);83!T*t. -VJaii.,'il9JS" /'-'i:""-}^; ■ ".■"''' ' 'j '' ',v. ; "'''■'','■,!, ' '-' , 

285. P>BKEa, G-ltTi^Tha Movements of" ihe Tentacles. in',Aotiniana. Jour. Exp 
, . Zooi.,»a (1)^96-110. 'j!m.,i9iT. '' ' -: ' / _ '';••" , j- ■-, 

286. pABKgS,l!G. H,--r:PedalLcico!l()fliiioHiin-A!ctinians. ibHr.Exp.Zoai.,aS (l):Ui- 

'■ =■ ,'■ 524'./'jin.,lSlj/. '"-f'-\ '/t:-;_ ' ■^_.-- ■■, ,' '^ ; ■ , '■ - , -, :- 

'rj|87. PiSKBi^ G. H.— Tli? Bespbnscs of Hydroids to Gravity. Proc. Nat. Acad. Sci., 

;:':-" 'S C2):72-T3-. S'*b5il»I7-, -:r^.- ■[^■,-'' ..'f :-■'- " ' ..-> 

2S8< Cotjs, 'W.pV^'Tlie! BeasitSi^ns; of -ittftsophila amjislpphila Lpew to Gravitj^^Cen- 

"/ ,1 ij-'ftiffegatibuiiand AjSp Cinrcntj. tToor. Ajoim.' Benaviai^, 7 (l) : Tl^iO. Jan., 1917. 

-289. |;(^di?J!fiHi!iI- M; D. — Seotropi^sm iiijPlanaria ii^ioajata.j Jour* Aniin. Behavior, 

. /}i?'''t"(i)V^I-86.'' ^aa. '1917. , ■ ^ ^; --,- '"'y.t' -'.■'■ '' ■ ''■ •'■;■' ^ ^' 

-^90, ' 'P.iiKKXS, g! H, — Atotijflw Behavior. Joiir.' Exp> ZoUl., »» («) : 193-229. ' Fel)., 

v'-'t 'W17.:- !.■ -'-;, "; '" ' ' .,-, ■■.■'.',/■■'' . ; '':;'■/ 

291.'- KmB»rsaiD,B,'S.I*.-r-''rhe Rhythmic Contractions of ihfe Mantle of LameUibraiohs. 
Wjour.Ejii.'^ZboU'2a(2):23I-!^9. ;ycb.,191T. ');-.' -.~.-, ' . ' 

29!!i KliiD,i'nii.i,>A."(i!.'4- The Reactions ,bf the 'JSfbjteoplioraBC of the Itprjied, Toad. 
'f', ' Proe?cfej;; Acad. Sci., %{3)-!202ffp8, Mar.,'l9liv" '" ' '■"?:>-. ,, 

i!93. RED;piBi.b,A.'^tI.-^TJic Coordination of the 5telan;ophore,4teactions oftlib Homed 
,:, 1 •••Tb.id. ProEljSfat.'AcaSvScJ.,* (B): 204-205^^^^^^ . , , ' . 

■394. " Po^ P, H.^.The.'jfatii'bdncttoik of iWesta^fiSanAfeiiM'p'Berniuaii. \ Bull. Mas. , 

;. '^ : •,ebTO.'zbBi.iei{6).:lir,-,i3i,a;i)i8. Ma^^ ■' , ': ,, >-■ ;, ,1 

295, Van iI?it?EN,ArP.7;^;The Skin of.the Eatiiah (Amiorus nebujoaua) as a Re-'' 
■ ,~- r. jpcpfi^ebrgantelJghW' Ap*ri (2) :212^Zlfi': S^pfci 1917. 

?9B. ,'Pi1^«,GiivP.,Ajn>VAJ!rI^B»SEiit/Atp.;--^;a^^^ , 

■^ ' { U(sbuio8tts, to MetaHic.ajid JS'bit.mefcs^lic Rods. Aiiiqi>; Jbnr.Jiphyjflol., 44 (8) :. , 
■•>"^ J '.40^1207 pet,, 1917. '•/ _y't: ,'-' i' "'Ij-^M '''' ^ _■■' _ ' ''■^''■-'i '"'■■- 
Wl. Pa^brv G.,H.vi3?he Pbdai LoeftSijotfiJn of tj!8f;Sea-H:are,A^ysfei;_b?(lifornica. 

''---V' ■■■^oj&'Ejqp,zoi3K^»4;(i)--as9-^4f'-^fc^ ;: '' ':c ;',, /■''•..-.;.:'•■ ^ 

298. PAirtf^K, Cr. iri^jajD Van Hm;9E5rj^.^.--'Th6 RecaptMwtof JHTeehanioal^tiniuIi,-' 
7, , by t^e ^fein, Iiater4UI4tJc Oi^ganj '^E'ars, in Fishesj e8]^,ecf»ll3r in-Ajninnrt" , - 
■■,/■'■ v;Amra'.|irwuvPlibrsioiji^'|';(*):'49?:^fe' firev,r;,-i917.X.;" ':->--,, [ 'hj .'/''■'' ', ■' 
•29IS: PABSSiSij a'li.--Tte!PbsfeirbfSticliioninthe^a-Jl'nsmon^iiW^ Exp. 

■ -i ■ zoai.',a4'(2)r2is-2^2.,'-2iroK;9i7^' ■ '■',>:. ''i,'/" ; -^ :, 



CONXaiBUTIONS FROM THE ZOOLOGICAL LABORAXOKY Of 
THE MUSEUM OF COMPABATIVB ZOOLOGY AT HARVARD 
COLLEGE. <C<m<wie<J.) - 

800. Pabkkb, G. H. — The Acttyjtks of Coiymorplia. Jour. Exp', ZpSh, H-i "<2) : S,U3- 
-331. Nov., 1917. " ^'' ' :, ' ^ i. „/; 

sal. Stbihqbb, C. E.-^Tlle iSIeans of Locomotion In Plahariaiisi Proc. Nat. Aead.,, 

__, Sci.,» (12)^:691-6927, Dec, 1917.. ^'. . ; , " -,.■-,• -' -' _ 

302. OlmstbDi J": it. D . — iw Be'geiioi-a^kia of Triangiilsr Pleees'of PJinariS, njacHilata. 
' . J A^tudy in Polarity. Jonr. Exp. ^ool., »5 (1): 157-176. ,. Feb., 1918-.-. ' 

303. iHboht, S. —The Phyaiology of Ascidia atra L^saoip'^ I. General Ptysiplogy. 
304.1 II. Sensory Physiology. J6ur. Exp. .26Bl.,3S(l.)j229-299. FebVi 1918.; 
305. HbohTjS. — Id. HI. The BHioaSystcm. AiW»r.J<iur. Physiol., 45 (3J :167-18r; 

■ ' Feb., 1918, '[-■_: "■ --' .1^;-;:,.": ;';._A ^ J. ■-. .- ^;'' c-' , 

'^66. Bn*T, A. W.,1.;. —The tleactlons of theljiei^aophoresof Amiiwnia to-Light atid 

^-Aarenftlin.'. Pjoc; Nat. Acad; Sei., 4(3) :58-6p.: Mar-.., 1918. . . V, -"" ■ 
^i)T. WiLTON, A, C— The OBg^enesis and-Early Erabryolo^of Asoaris oanis Weriier, 
Jo]ir.jMorDh.,.S'0 (2) : 627^603. -^ Mar,, 1918. ~ '■; . ;_, -.,-" --.:,,' 

'308. OtMSTBD, J. M. D. — Experiments, on the' Nature of the SenSe" of SnwU in the 
Cbmmoti\'Oatflsh,' T^miurus nebuloslia (Lesiieur)^ ; Amer. -lour. Physiol., 40 
(6) •443-468. A4ig.,a918.. ; , 'r; - .- . ,, . . , '. ,-. 

.309. SBbmBLD, A. C— Tlie TPhysiology <rf the MJelan'ophores ol the Hphied-.TS""*''. 
Phrynosotna. Joar.E^'p.^Zbcil., a« (2).;27MSS. July, 1918. ..,- ',,' ' -?' 
-310. BkooksJ-E. S. — Eeaotions of Frogs^ to-Bfeat and CoJ,d. Amer. JpurT^ysioL, 
'^' 46.(5)': 493-501." Au^., 191S7 ' . " *~ - '" -■ - , , - ;■ .. .~: , / 
311. Cobb, P. H. — Autonomous Beapenses of the Labial Palps of Anodonta. PSbc.\ 

-N#..Acad. Sci.,4(8):234r-'235. 'Aug., 1918L{ ' ^, ^ . :""'---■ ; 
S12. lBwhr,]tti — Th^ Nature of* Sensory Stimulation, by Salts. Amer. Jonir.Pliyaiol., 
' 7 4'r (2) :26MF-. Noy-., 19I8.\ ., - "' -' .. ' -,.:;-k., 

818. _PAl«CB5i <}. H. — The Eate of Trivnstaission in the Nerye Net of the Co,ejent6r»tA; 

Jo-ur.,a,en..Biy8iol.T 1(2): 231-236, Not.,191-8.' . -. .f*'.^ ,''. 

3U. BieNJjtj A. J.^Tbe^^flect oFAdrenin on tbePiginent Migration in the Mel^no^' 
'- phores of the.Slciaandinthe Pigme'ntCells of the Bfetuia.6f the Frqg; .Jouir.-, 
Exp. Zo8li-,8T,(s'): 391-396. ';jan., 1919. .. '. :,',..\ •' ' '— ^.', 

8id. JoRDiN, H. ^- Couoerning ReissnerV'Fiber in TeJeostfi. Sffdx- Coinp. JSTen^oL, 

.•{O (2).; 217-227, 1 pi. Feb., 1919. .. - - _ '• , , j, - ■ '^ ' 

316. Pabkek, G7 H. — The Ojganizati«i of Kehilla. J5ur. Exp. ^Bl., a?^Cit) '. 499- 
,,,. -807. i"eb., 1919: ~ . -^^'- ''■ , , , " _; -"'' _ :') 

;U7. ,Huj(T, H. E. — KegenerativePhenc^na^a, following TiheB^OTaJ-ofthe.pigestlyfi'-. 
,' liibe and the Nerve Cord of Sarthwornis, Bull. Mu^; Comp. Zool.i <»a:(lf^t''' 
r^ ,569-581,-1 pi.. Apr. j 1*9. ' V r - .r -~ .' ._ - - ' ~%: '', 

-318;^ Davis, Bi W.— Asexual Multiplication ' ami •Regeneration i^-.'Bagartia* luoiae 
-- "ECTrill. :irou> Exp. Zbm., 88 (2): 161-204. May, 1919. '^ ; .'-^"^ 

-S19.J JPabeeb,.G. H.vf-The' Effect^ of the i)a6t 'Wiatii; on tjie OcpurrSoee ofSagartiia 

'/ ' - l^iCiae-Veirill.'' Amer. Nat-., 5iJ <626)i280-2'81., ;Ma,y^une, 19I»?4 ' ' 

820. MiNNicfi, 6. E. —The Photic Beaotapns of theSoney-Bae, A-pi's ' 
Jonr. Exp. ZooV., 3» (3)-; 343-426. ' Nov., 1919.