■ 2 ^ m :t >fl ■flllij m^M mm m4m pi liU^M I V/ 1 ifr*SF&git #11 « -?r -II l» kf£*s% N^ArcTOpi^ ffitfluirgeP.:!:' Jlplil ^Igr/ ISP^v V, si^o§£b\ i0T'm Steww ®S| & <& §3ghJr *;?spl ifeSI JuaV^O,, §1^1 iTi 5 £v' "y" foVro. [4 VS,,. ^fsK-j W0 ifi pib\ ^-+7c'.f )o«e <4.C “W - Jtv. j^5 /T f°p«“-. &5&IS ftBti fe&T tegs b^MS t|i|gF ^gp \%iSa, J®li feis ISSil !?8S| |®1& £•'0^ /plpK \ a^ ipriNIft ; -i* vS> 'V «Ss® siip ZOOLOGIC A SCIENTIFIC CONTRIBUTIONS OF THE NEW YORK ZOOLOGICAL SOCIETY VOLUME 48 • 1963 • NUMBERS 1-12 PUBLISHED BY THE SOCIETY The ZOOLOGICAL PARK, New York NEW YORK ZOOLOGICAL SOCIETY GENERAL OFFICE 630 Fifth Avenue, New York, N. Y. 10020 PUBLICATION OFFICE The Zoological Park, Bronx, N. Y. 10460 OFFICERS PRESIDENT VICE-PRESIDENT SECRETARY TREASURER Fairfield Osborn Laurance S. Rockefeller George W. Merck David H. McAlpin SCIENTIFIC STAFF: William G. Conway . . Director, Zoological Park Christopher W. Coates . . Director, Aquarium John Tee- Van General Director Emeritus ZOOLOGICAL PARK Joseph A. Davis, Jr. . . Curator, Mammals Grace Davall Assistant Curator, Mammals and Birds William G. Conway. . Curator, Birds Joseph Bell Assistant Curator, Birds Herndon G. Dowling. Curator, Reptiles Charles P. Gandal. . . Veterinarian Lee S. Crandall General Cur ator Emeritus Roland Lindemann .... Consultant in Mam- mal Management AQUARIUM Paul Montreuil Curator Carleton Ray Associate Curator Ross F. Nigrelli Pathologist & Chair- man of Department of Marine Biochem- istry & Ecology Klaus D. Kallman. . . .Geneticist C. M. Breder, Jr Research Associate in Ichthyology Harry A. Charipper. . . Research Associate in Histology Sophie Jakowska Research Associate in Experimental Biology Louis Mowbray Research Associate in Field Biology GENERAL William Bridges . . Editor & Curator, Publications Dorothy Reville . . Editorial Assistant Sam Dunton Photographer Henry M. Lester. . Photographic Consultant DEPARTMENT OF TROPICAL RESEARCH Jocelyn Crane Director Associates: Jane van Z. Brower Lincoln P. Brower William G. Conway Julie C. Emsley Michael G. Emsley AFFILIATE L. Floyd Clarke . . . Jackson Hole Biological Research Station EDITORIAL COMMITTEE Fairfield Osborn, Chairman William Bridges Joseph A. Davis, Jr. Christopher W. Coates Herndon G. Dowling William G. Conway Ross F. Nigrelli Lee S. Crandall William K. Gregory Donald R. Griffin David W. Snow John Tee- Van Dirprtnr Contents Issue 1. May 22, 1963 PAGE 1. Weights and Wing-lengths of Some Trinidad Birds. By D. W. Snow & B. K. Snow. Text-figure 1 1 2. The Reproductive Behavior of the Green Sunfish, Lepomis cyanellus. By John R. Hunter. Text-figures 1-7 13 3. Studies on the Endocrine Glands of the Salmonoid Fish, the Ayu, Pleco- glossus altivelis Temminck & Schlegel. V. Seasonal Changes in the Endo- crines of the Land-locked Form, the Koayu. By Yoshiharu Honma & Eimitsu Tamura. Plates I-III; Text-figure 1 25 Issue 2. August 22, 1963 4. The Mammals of the Atlantica Ecological Research Station, Southern Rho- desia. By Robert T. Hatt. Plates I-IV; Text-figures 1 & 2 33 5. The Spawning and Early Development of the Atlantic Parrot Fish, Spari- soma rubripinne, with Notes of Other Scarid and Labrid Fishes. By John E. Randall & Helen A. Randall. Plates I & II; Text-figures 1 & 2 49 6. Massive Aggregations of Large Rays and Sharks In and Near Sarasota, Florida. By Eugenie Clark. Plates I & II 61 Issue 3. December 26, 1963 PAGE 7. Experimental Studies of Mimicry. 7. Relative Palatability and Mullerian Mimicry among Neotropical Butterflies of the Subfamily Heliconiinae. By Lincoln Pierson Brower, Jane Van Zandt Brower & Charles T. Collins. Plate 1 65 8. A Morphological Study of Imagine Heliconiinae (Lep.: Nymphalidae) with a Consideration of the Evolutionary Relationships within the Group. By Michael Emsley. Plate I; Maps 1-17; Text-figures 1-153 85 9. Spontaneous Tuberculosis in Fishes and in Other Cold-blooded Verte- brates with Special Reference to Mycobacterium fortuitum Cruz from Fish and Human Lesions. By Ross F. Nigrelli & Henry Vogel. Plates T-VI. . 131 Issue 4. December 31, 1963 10. Some Genetic Studies of Mullerian Mimics in Butterflies of the Genus Heliconius. By P. M. Sheppard. Plates I & II 145 11. The Electroretinogram of Heliconius erato (Lepidoptera) and Its Possible Relation to Established Behavior Patterns. By S. L. Swihart. Plates I & II; Text-figures 1-6 155 12. The Display of the Blue -backed Manakin, Chiroxiphia pareola, in Tobago, W. I. By D. W. Snow. Plates I-III; Text-figures 1-3 167 Index to Volume 48 177 ZOOLOGIC A SCIENTIFIC CONTRIBUTIONS OF THE NEW YORK ZOOLOGICAL SOCIETY VOLUME 48 • ISSUE 1 • SPRING, 1963 PUBLISHED BY THE SOCIETY The ZOOLOGICAL PARK, New York Contents PAGE 1. Weights and Wing-lengths of Some Trinidad Birds. By D. W. Snow & B. K. Snow. Text-figure 1 1 2. The Reproductive Behavior of the Green Sunfish, Lepomis cyanellus. By John R. Hunter. Text-figures 1-7 13 3. Studies on the Endocrine Glands of the Salmonoid Fish, the Ayu, Pleco- glossus altivelis Temminck & Schlegel. V. Seasonal Changes in the Endo- crines of the Land-locked Form, the Koayu. By Yoshiharu Honma & Eimitsu Tamura. Plates I-III; Text-figure 1 25 Zoologica is published quarterly by the New York Zoological Society at the New York Zoological Park, Bronx Park, Bronx 60, N. Y., and manuscripts, subscriptions, orders for back issues and changes of address should be sent to that address. Subscription rates: $6.00 per year; single numbers. $1.50, unless otherwise stated in the Society’s catalog of publications. Second-class postage paid at Bronx, N. Y. Volume 47, Part 4 (Winter, 1962), was published on January 24, 1963. 1 Weights and Wing-lengths of Some Trinidad Birds1 D. W. Snow & B. K. Snow Department of Tropical Research, New York Zoological Society, New York 60, N. Y. (Text-figure 1) Introduction A LTHOUGH it is nearly 20 years since /\ Amadon (1943) drew attention to the jL JL fact that the weight of a bird is the most satisfactory single measure of its size, in most studies involving the size of birds wing- length still has to be used as the measure, as too few weights are available. Great numbers of weights are now being recorded for some north- temperate species, especially migrants trapped at banding stations. But so far comparatively few weights of tropical species have been pub- lished, though for the neotropical region men- tion must be made of Haverschmidt’s data from Surinam (Haverschmidt, 1948, 1952) and the bird weights from Trinidad already recorded by Junge & Mees ( 1 958 ) 2. Hence is seems worth while summarizing over 4,000 weights which we collected in the course of 3 Vt. years’ trapping of birds in Trinidad. Wing-lengths are also given for the larger samples, primarily so that the coefficients of variation of weight and wing- length can be compared. Acknowledgments We are most grateful to R. P. ffrench for sup- plying 92 weights. They were taken with the same type of balance and by the same method Contribution No. 1,038, Department of Tropical Research, New York Zoological Society. 2The specimens collected by Mees were weighed after they had been stored for some time in a frozen con- dition (G. F. Mees, in lift.). Especially in the smaller species, this evidently involved some loss of weight, as is most evident when the weights of hummingbirds re- corded by Junge & Mees are compared with those given here. as we ourselves used, and are incorporated with those obtained by us. We would also like to acknowledge the help given by members of the Trinidad Regional Virus Laboratory. A large number of the weights recorded here were ob- tained while one of us was taking part in the field studies of the laboratory, and the weighing added significantly to the time taken over work which was primarily virological. R. E. Moreau kindly criticized this paper in draft. The whole program, of which this study forms a part, was generously supported by National Science Foun- dations grants G 4385 and G 21007. Variation in Weight of the Same Individual Many individual birds were trapped more than once in the course of the work, some of them several times. This raises the problem whether, in presenting the data, each weight should be included or only one for each individ- ual. If only one weight, e.g. the first recorded, is given for each individual, the range of weights is reduced for many species and a considera- ble amount of variation is lost in which the iden- tity of the individual is of no relevance. For instance, many females were trapped during the breeding season, when they were heavier than usual, and outside the breeding season, when their weight was “normal;” and there were other vairations in the weight of the same individual the cause of which was unknown. If the mean weight were given for the individuals trapped more than once, the range of variation of the samples would be even more seriously reduced, though the accuracy of the mean would be im- proved. Alternatively, it would be possible to in- clude for each individual the greatest and the 1 2 Zoologica: New York Zoological Society [48: 1 least weight recorded, but this would have the opposite effect, of biassing the samples towards the extremes. On the other hand, if all weights are included, those individuals that were weighed more than once will have undue influ- ence on the mean. No completely unobjection- able means of presenting the data seems possible within acceptable limits of space, but on balance it has seemed best to include all weights, and to indicate after the number in the sample the number of individuals involved, if it is different. There were more repeated trappings of the same individual Black and White Manakins ( Manacus manacus) than any other species. Text-fig. 1 shows the weights of those individuals trapped ten times or more compared with the 0 d i — i — i — r « i i i i s » i i b t rn — i 9rn. I*t 15 /6 17 18 19 20 21 11 23 Text-fig. 1. Weights of Manacus manacus. All adult males, all females, and all individuals trapped ten times or more. 1963] Snow & Snow: Weights and Wing-lengths of Some Trinidad Birds 3 whole sample. The two males showed a rather small range of weights, and all the females much more, a difference connected mainly with their breeding activity. For individual females, the heaviest weights were recorded during the egg- laying season, and the lightest just after the breeding season and, in one case, while depend- ent young were being fed. A series of seven weights of one individual female was especially revealing (weights in grams) : May 23 16.5, 16.5 (two captures on the same day) June 3 21, 18.5 (two captures, before and after laying) June 14 17 June 28 16 July 17 15 The greater variability of the females’ weights compared with the males’ is reflected in the co- efficients of variation (7.7 and 7.0 respectively, Table V). In species of moderate or large size, weighing 20 gm. or more, successive weighings of the same individual males were usually consistent enough for individuals to be characterized as “heavy,” “average” or “light” after they had been weighed three or four times. For example, the two male Silverbeaks ( Ramphocelus carbo) which were trapped four times or more weighed on succes- sive occasions: (1) 32.5, 32.5, 33.5, 31, 30, 33 gm. (2) 28.5, 30.5, 29, 29.5 gm. The mean weight of all adult male Silverbeaks was 29.5 gm. Thus the first was rather a heavy bird, the second average. For females, with their greater variability, and for small species, with their smaller range of weight, few individuals were trapped often enough for such differences to be apparent. A striking but numerically unimportant source of variation in weight was infestation by subcutaneous maggots of Philornis flies. These commonly infest nestlings in Trinidad but rarely adults. Two parasitized Black and White Mana- kins were trapped. One, which harbored nine larvae of varying sizes, weighed 16.5 gm. on cap- ture and 15.5 gm. when it had been ridded of its parasites. The weight of the second bird, with only one very large maggot, was reduced from 17 to 16.5 gm. Diurnal Variation in Weight There was evidence of slight change in weight in the course of the day in three species of which especially large numbers were trapped, Glaucis hirsuta, Manacus manacus and Coereba flaveola. In Glaucis, birds of comparable wing-length trapped after midday averaged a little heavier than those trapped before midday. For birds of wing-length 58-60 mm. (almost certainly nearly all females), for which the sample is largest, the difference of 0.3 gm. is statistically significant (Table I). In Manacus, 18 individuals were trapped more than once on the same day and omitting one, which laid an egg between its two captures, all except one were either the same weight or a little heavier at the time of their second capture. The average rise in weight from 0700 to 1700 hours was 0.73 gm. In Coereba the mean weight of adults rose significantly from 10.25 gm. for birds trapped before 0800 hours to 10.85 gm. for birds trapped after 1600 hours (Table II). Since our work was entirely with living birds we do not know to what extent the diurnal in- crease is due to an increase in stomach contents or reserves within the body. But in any case it amounts to only about 5 % of the birds’ average weight, so that no serious error is introduced by combining, as has been done, weights obtained at all hours of the day. Table I. Diurnal Variation in Weight in Glaucis hirsuta (Birds of wing-length 58-60 mm.) Weight (gm.) Trapped before midday ! Trapped after midday 8 2 1 7.5 6 2 7 26 15 6.5 35 14 6 27 2 5.5 7 - Total 103 34 Mean weight 6.50 6.79 S.D. 0.55 0.46 4 Zoologica: New York Zoological Society [48: 1 Table II. Diurnal Variation in Weight in Coereba flaveola (All adults, except two egg-laying females) Weight (gm.) Time of capture Up to 08.00 08.01-12.00 12.01-16.00 After 16.00 12.5 2 _ 1 12 1 5 2 2 11.5 4 11 5 2 11 14 26 9 7 10.5 18 27 14 2 10 19 21 2 5 9.5 16 17 2 1 9 4 5 1 — 8.5 — 1 - - Total 76 115 35 20 Mean weight 10.25 10.49 10.73 10.82 S.D. 0.72 0.80 0.69 0.79 Seasonal Variation in Weight Seasonal changes in weight were detected in females of species of which especially large num- bers were trapped, their mean weight being, as would be expected, greater at the egg-laying season than at other times of year. But the dif- ferences are not very great, as breeding seasons are long and normally only a small proportion of the females are engaged in egg-laying at the same time. In Manacus, for which the largest number of female weights were recorded, the mean of 83 female weights in May-June, the height of the egg-laying season, was 17.11 gm., compared with 16.02 gm. for 50 weights in No- vember-December, the middle of the off-season, a difference of nearly 1% of the over-all mean weight. In the flycatcher Pipromorpha oleaginea, 27 females trapped in the months March-June, the main egg-laying season, averaged 11.6 gm., compared with 11.1 gm. for 39 trapped during the rest of the year, a difference of about 4% of the mean weight. Again, as for diurnal variation, it has not seemed necessary to take this source of variation into account in presenting the tabu- lated data, and in any case the breeding season of many of the species is too poorly known to make such a course practicable. Adult males showed little seasonal variation in weight, but the mean tended to increase slight- ly during the moult. In the Golden-headed Man- akin ( Pipra erythrocephala) the large series for the different months reveal that birds trapped during the main period of moult (August-Oc- tober) were slightly but significantly heavier than those trapped at other times of year (means 13.25 and 12.57 gm. respectively). This differ- ence is due entirely to those individuals that were actually moulting at the time of capture. Those trapped in the months August-October that were not moulting weighed the same as those trapped in the other months of the year (Table III) . In Manacus the difference was even greater: the mean weight of moulting adults trapped in August-October was 19.9 gm., and that of non-moulting males in the same months 18.2 gm. A hint of the same was found in other species too: for instance, in Ramphocelus carbo the heaviest weights for adult males were nearly all of moulting birds. Immature males of Manacus are a special case. They begin by resembling females both in plumage and weight, being considerably lighter than the adult males (mean of adult males, 18.5 gm.; females, 16.8 gm.). Gradually their weight increases, presumably through the development of the specialized musculature connected with their complex display (Snow, 1962 a), until by the time they moult into adult plumage they have practically reached full weight. For instance, the same individual, trapped in November, 1959 (five months after fledging), weighed 14 gm.; in April, 1960 (still in juvenile plumage), 17 gm.; in June, 1960 (just before moulting to adult plumage), 17.5 gm.; and in adult plumage, in May and August, 1961, 17.5 and 18 gm. Local Variation in Weight Some local variations were found, but as the data are few and the subject was not sufficiently studied, they will only be briefly mentioned here. Manacus, Turdus species and some other birds trapped in flat country near sea level south of the Northern Flange were on average lighter than those trapped in the Northern Range, and their wings were a little shorter. For most species the numbers were rather small and there was a 1963] Snow & Snow: Weights and Wing-lengths of Some Trinidad Birds 5 Table III. Weights of Adult Male Pipra erythrocephala Weight (gm.) All months August-October only Not moulting Moulting 17 1 — — 16 1 — — 15 8 — 6 14.5 8 2 4 14 25 2 13 13.5 41 6 14 13 56 6 13 12.5 64 10 5 12 51 7 3 11.5 29 3 — 11 6 — — 10.5 1 1 - Total 291 37 58 Mean weight 12.79 12.70 13.56 S.D. 0.97 0.88 0.79 considerable overlap between the measurements from the two areas, so that it has not been thought necessary to give them separately. But in Turdus fumigatus the difference was so great that they are given separately in the tabulated data that follow. The species concerned were mostly forest birds, and south of the Northern Range they were trapped in mainly cultivated areas. It is possible that less good feeding condi- tions had resulted in a smaller size. Alternative- ly, the difference might be genetical and related to the different altitudes of the localities, though if this were so it would imply a surprising de- gree of genetic isolation between populations only a few miles apart. Another locality where weights differed from those obtained elsewhere was Chacachacare, a very dry island off the northwest corner of Trini- dad. Here the 55 adult Coereba flaveola trapped on two visits, in April and October, were on average markedly lighter than those trapped on the main island of Trinidad (Table IV) . In wing- length they did not differ from birds trapped elsewhere. On both visits these birds were all moving across an isthmus from one part of the island to another, in a mass movement that was so prolonged and involved so many birds that we suspected a true migration, though Coereba has not previously been thought to be migratory. Table IV. Weights of Coereba flaveola on Main Island of Trinidad and Chacachacare Weight (gm.) Main island Chacachacare 13 1 12.5 4 — 12 9 — 11.5 21 — 11 54 2 10.5 58 7 10 45 8 9.5 34 12 9 9 14 8.5 1 3 8 — 5 7.5 — 2 7 - 2 Total 236 55 Mean weight 10.50 9.27 S.D. 0.79 0.98 6 Zoologica: New York Zoological Society [48: 1 Variation of Weight and Wing-length Compared Table V gives the coefficients of variation of the 18 samples for which the standard deviations of both weight and wing-length have been cal- culated. The coefficients of variation for each are rather consistent, those for weight being mostly from 6 to 8 and those for wing-length mostly from 2 to 3. But, as Amadon (1943) points out, that does not mean that weight is really more variable than wing-length. Since wing-length is linear and weight three-dimensional, the com- parison needed to test this point should be be- tween the coefficients of variation of wing-length and the cube root of the weight. For many of the larger samples represented here this would in- volve extremely laborious calculations and it has not been attempted. Within age and sex groups, no positive corre- lations between individual weights and wing- lengths could be demonstrated, even though some large samples are available (e.g., 239 for adult male Pipra). But if all individuals of a species are lumped together, positive correla- tions are naturally found in species in which the male is longer-winged and heavier than the fe- male. Thus in Glaucis, with a large range of weights and wing-lengths, the correlation co- efficient was found to be 0.58 ± 0.04. Specific Section Methods Within a few minutes of being caught, each bird was placed in a cloth bag, the weight of which had already been recorded, and weighed with a spring balance accurate to 0.5 gm. Regu- lar checking of the weight of the bag was found to be of great importance, especially when weighing small birds, as changes in humidity, which were most rapid in the morning, could result in alterations of up to 2 gm. The spring balance itself was regularly calibrated with lab- oratory weights, and showed no change in its readings. The wings were measured in the naturally closed position, with the feathers lying in then- natural curvature (the “natural chord” of bird observatory workers) . Statistical treatment The weights are given in full for samples of five or fewer, weights from the same individual being separated by commas, those from different individuals by semicolons. When more than five weights were obtained, the number in the sample is given in parentheses, together with the number of individuals involved, if different, fol- lowed by the range and the mean. If the number in the sample exceeds 20, the standard deviation is then added. Standard deviations are given only for samples of known sex. Data are given sep- arately for age and sex classes, as far as possible. Thus for the manakins, honeycreepers and some tanagers, immature males are given separately from adult males. But juveniles (here defined as birds showing incompletely grown plumage and/or juvenile gape-flanges) are omitted unless a sample of five or more was obtained, as their weights are too variable for one or two alone to Table V. Coefficients of Variation of Weight and Wing-length in Eleven Species Coefficients of variation Weight Wing-length Columbigallina talpacoti $ 7.3 2.1 9 7.4 2.0 Glaucis hirsuta $ 7.4 2.7 9 8.8 2.1 Pipra erythrocephala $ 7.6 2.1 9 6.9 2.6 Manacus manacus $ ad. 7.0 2.1 $ imm. 6.9 2.2 9 7.7 1.7 Tardus nudigenis $ 7.5 3.4 Coereba flaveola $ 6.6 2.4 9 6.5 3.0 Agelaius icterocephalus $ 5.7 2.8 Tanagra violacea $ 6.3 3.1 Ramphocelus carbo $ 7.5 2.2 9 7.7 2.3 T achyphonus rufus $ 5.4 2.5 Volatinia jacarina $ ad. 7.2 2.7 1963] Snow & Snow: Weights and Wing-lengths of Some Trinidad Birds 7 be meaningful. Very heavy females, trapped in the breeding season, that were known or sus- pected to be about to lay eggs, are kept separate from the rest of the samples. In the case of mi- grant species, the weights are given separately for each month. Wing-lengths are given for samples of five or more individuals of known sex, only one wing- length (the first recorded) being given for in- dividuals measured more than once, except when there was a change of plumage from immature to adult. All weights are in grams, and wing-lengths in millimeters. Columbigallina passerina Weight. Male: 35.5. Columbigallina talpacoti Weight. Males: (38) 40.5-56.5, 48.1. S.D. 3.5. Females: (36) 35.5-51.5, 44.8. S.D. 3.3. Wing. Males: (40) 85-91, 87.5. S.D. 1.8. Females: (40) 82-88, 85.5. S.D. 1.7. Columbigallina minuta Weight: Male: 35.5. Unsexed: 34; 35; 35.5. Leptotila verreauxi Weight. Unsexed: 123. Touit batavica Weight. Unsexed: (7) 52-59.5, 55.6. Piaya minuta Weight: Unsexed: 35.5; 36; 36. Crotophaga ani Weight. Males: 104.5; 107, 118.5. Unsexed: (12) 79-116.5, 100.3. (11 weighed 92-116.5.) Otus choliba Weight. Male: 114.5. Unsexed: 120.5. Glaucidium brasilianum Weight. Unsexed: 66; 70; 71; 77 . Steatornis caripensis Weight. Males: 405; 410; 480. Unsexed: 375; 375; 410; 425; 435. Chaetura chapmani Weight. Unsexed: 25.5. For fuller details for Chaetura and Cypseloides species, see Snow (1962 b). Chaetura cinereiventris Weight. Unsexed: (43) 12.5-16, 13.8. Chaetura spinicauda Weight. Unsexed: (21) 13-18, 14.2. Chaetura brachyura Weight. Female: 30. Unsexed: (10) 17-22, 18.8. Cypseloides zonaris Weight. Male: 60. Female: 74. Unsexed: 63.5. Cypseloides rutilus Weight. Unsexed: 20; 22. Panyptila cayennensis Weight: Unsexed: 18.5. Glaucis hirsuta Weight. Males: (37) 6-8, 7.3. S.D. 0.54. Females: (37) 5.5-8, 6.7. S.D. 0.59. (One bird weighing 7 gm. laid an egg while being weighed, and the sample probably includes a few other egg-lay- ing birds.) Unsexed: (224) 5-9.5. 7.0. (A few of the birds weighing 7 gm. or more were probably egg-laying females, but most were adult males by plumage and beak- color.) Wing. Males: (23) 59-67, 64.0. S.D. 1.7. Females: (27) 55-61, 58.3. S.D. 1.2. Phaethornis guy Weight. Males: (9) 6-7, 6.4. Females: 6; 6.5; 6.5. Unsexed: (86) 5.5-8, 6.3. Wing. Males: (12) 60-67, 63.1. Phaethornis longuemareus Weight. Males: (6) 3-3.5, 3.2. Females: 3; 3; 3. Unsexed: (23) 2. 5-4. 5, 3.2. Wing. Males: (7) 41-43, 42.0. Females: (5) 42-44, 42.4. Florisuga mellivora Weight. Unsexed ( female plumage ): 6; 6.5. Anthracothorax viridigula Weight. Female: 11 (probably egg-laying). Anthracothorax nigricollis Weight. Males: (7) 6.5-7.5, 6.9. Females: (8) 6.5-7.5, 7.1. Unsexed ( female plumage): (12) 6-8, 6.9. Wing. Males: (5) 64-66, 65.2. Females: (9) 63-66, 64.7. Chrysolampis mosquitus Weight. Males: 4; 4.5. Unsexed (female plumage): 4.5; 5. Chlorestes notatus Weight. Males: (13) 3.5-5, 4.1. Females: 3.5; 4; 4. Unsexed ( female plumage): (6) 3-4.5, 3.7. Wing. Males: (14) 49-53, 50.6. Females: (5) 46-49, 47.2. Polytmus guainumbi Weight. Unsexed: 4.5; 4.5. 8 Zoological New York Zoological Society [48: 1 Amazilia chionopectus Weight. Males: 4.5; 4.5; 4.5; 5. Females: (7) 3.5-5, 4.4. Unsexed: (16) 3.5-6, 5.0. Wing. Males: (8) 51-53, 52.1. Females: (7) 48-52, 50.0. S aucerottia tobaci Weight. Males: 4; 4.5; 5; 5. Females: (5) 4-4.5, 4.2. Unsexed: (83) 3.5-6, 4.7. Wing. Females: (6) 48-50, 49.5. Heliomaster longirostris Weight. Males: 6.5; 6.5. Unsexed ( female plumage): 6; 6.5. Trogon strigilatus Weight. Males: 77, 99. Trogon collaris Weight. Female: 56. Trogon violaceus Weight. Males: 55; 55.5. Females: 48.5, 52.5; 51.5. Chloroceryla americana Weight. Males: (7, 5 different) 28-32.5, 30.4. Females: 32; 34; 36.5. Chloroceryle aenea Weight. Unsexed: 14.5. Momotus momota Weight. Females: 99, 102, 133 (egg-laying); 110. Unsexed: (6, 5 different) 102-123, 114.1. Galbula ruficauda Weight. Male: 25.5. Females: 24; 33.5 (probably egg- laying). Piculus rubiginosus Weight. Males: (6, 5 different) 51.5-59, 55.4. Females: 52.5; 56; 61.5. Celeus elegans Weight. Males: (6, 4 different) 112-129, 120.3. Females: (8, 5 different) 93.5-133, 113.9. Veniliornis kirkii Weight. Male: 37. Unsexed: 35; 36.5. Dendrocincla fuliginosa Weight. Females: (8, 6 different) 31.5-38.5, 34.9. 46 (probably egg-laying). Unsexed: (67, 41 different) 31-43.5, 37.6. Wing. Females: (7) 95-101, 96.3. Xiphorhynchus guttatus Weight. Unsexed: (17, 6 different) 46.5-55, 50.8. Synallaxis cinnamomea Weight. Unsexed: 17. Certhiaxis cinnamomea Weight. Males: 13.5; 14. Female: 12.5. Unsexed: 12; 13; 15.5. Sclerurus albigularis Weight. Unsexed: (6, 4 different) 33-37.5, 34.9. Sakesphorus canadensis Weight. Male: 23.5. Females: 20.5; 24. Thamnophilus doliatus Weight. Males: (21, 19 different) 25-30.5, 28.0. S.D. 1.5. Females: (11, 10 different) 26-30.5, 27.8. 32 (probably egg-laying). Wing. Males: (18) 68-73, 70.5. Females: (15) 66-73, 68.5. Dysithamnus mentalis Weight. Males: 12.5 (immature); 14.5. Female: 13. Myrmotherula axillaris Weight. Males: 7; 8, 8.5; 8, 9.5. Females: 8; 8.5. F ormiciv or a grisea Weight. Unsexed (female plumage): 6.5; 9. Sclateria naevia Weight. Male: 23. Myrmeciza longipes Weight. Male: 28.5. Females: 23; 27. Formicarius analis Weight. Male: 62. Unsexed: 57; 61, 61.5, 62.5. Pachyramphus polychopterus Weight. Males: 19; 21.5. Pipra erythrocephalus Weight. Adult males: (291, 223 different) 10.5- 17, 12.8. S.D. 0.97. Immature males: (9) 12-13.5, 12.7. Females: (214, 171 different) 12-16.5, 14.1. S.D. 0.97. Weights of 16 and 16.5 were mainly recorded in the breeding season (March-August) and were probably egg-laying birds. Wing. Adult males: (183) 52-60, 56.7. S.D. 1.2. Immature males: (19) 56-60, 58.6. Females: (46) 54-62, 58.7. S.D. 1.5. Manacus manacus Weight. Adult males: (191, 93 different) 16-23, 18.5. S.D. 1.3. Immature males: (58, 47 different) 14- 19.5, 17.3. S.D. 1.2. Females: (344, 106 different) 14-21.5, 1963] Snow & Snow: Weights and Wing-lengths of Some Trinidad Birds 9 16.8. S.D. 1.3. All weights of 19.5 and above were recorded in the breeding season (February-August). Several of these were known to be egg-laying birds, and the others probably were. The above figures differ slightly from those given in Snow (1962 a). In the earlier paper, in order to examine sea- sonal variation, weights recorded after 11.00 hours were reduced by 0.5 gm., thus minimizing the effect of the diur- nal increase in weight. Here the ad- justment has not been made, in order that the figures should be comparable with those for other species. As a re- sult, for each of the three samples the mean given here is 0.3 gm. higher than in the earlier paper. In addition, two of the samples are larger, owing to the inclusion of later records. Wing. Adult males: (63) 51-55, 52.4. S.D. 1.1. Immature males: (41) 52-57, 54.9. S.D. 1.2. Females: (82) 53-57, 54.7. S.D. 0.95. Fluvicola pica Weight. Males: 12; 12. Females: 11; 11.5; 11.5. Tyrannus melancholicus Weight. Unsexed: 44.5. Legatus leucophaius Weight. Male: 21. Myiodynastes maculatus Weight. Female: 50, 68 (egg-laying). Unsexed: 49.5; 52.5. Pitangus sulphuratus Weight. Males: 58; 64.5; 67. Unsexed: 57; 58.5. Myiarchus tyrannulus Weight. Unsexed: 29; 31.5; 32.5; 33. Myiarchus tuberculifer Weight. Unsexed: 22. Contopus cinereus Weight. Unsexed: 13.5; 13.5. Empidonax euleri Weight. Unsexed: (14, 7 different) 11.5-13, 12.3. Myiophobus fasciatus Weight. Males: 10; 10; 10; 10.5. Females: 8.5; 9; 9.5. Unsexed: 9; 9.5; 10; 10.5; 10.5. Platyrinchus mystaceus Weight. Unsexed: (9, 4 different) 8-10.5, 9.7. Tolmomyias sulphurescens Weight. Unsexed: 16. Tolmomyias flaviventris Weight. Male: 13. Unsexed: (9, 8 different) 11.5-14, 12.8. Elaenia flavogaster Weight. Males: (14) 22.5-27.5, 24.6. Females: 23.5; 24; 24; 25. Unsexed: (11) 21-27, 25.0. Wing. Males: (18) 73-84, 78.7. Females: (6) 74-78, 75.7. Myiopagis gaimardii Weight. Female: 12.5. Unsexed: (7, 5 different) 12.5-14, 13.2. Sublegatus arenarum Weight. Unsexed: 11; 11.5. Phaeomyias murina Weight. Unsexed: (20) 8-12, 9.7. Camptostoma obsoletum Weight. Unsexed: (8) 6.5-8, 7.2. Leptopogon superciliaris Weight. Male: 13. Unsexed: (17, 6 different) 9.5-13, 11.9. Mionectes olivaceus Weight. Unsexed: 18. Pipromorpha oleaginea Weight. Males: (12, 11 different) 11.5-14, 12.5. Females: (7) 10-11.5, 10.9. 15.5 (egg- laying). Unsexed: (242, 159 different) 9-14.5, 12.1. Wing. Males: (16) 62-68, 64.8. Females: (6) 57-61, 58.7. Stelgidoteryx ruficollis Weight. Male: 15. Unsexed: 14.5; 15; 15.5; 15.5; 16. Juveniles: (7) 12.5-15.5, 13.9. Hirundo rustica Weight. Unsexed: 16; 18. Both birds were trapped on January 11, and were moulting wing, tail and body feathers. Thryothorus rutilus Weight. Males: 14; 16; 17; 17; 17.5. Females: 14; 14; 15. Unsexed: (18, 11 different) 13.5-18.5, 16.8. Wing. Males: (5) 55-62, 59.4. Troglodytes musculus Weight. Males: 13; 14. Females: 13; 13.5. Unsexed: (16, 13 different) 12.5-15, 13.9. Wing. Males: (7) 52-55, 52.9. T urdus al'bicollis Weight. Unsexed: (45) 45-62.5, 54.1. 66.5 (probably egg-laying female). 10 Zoologica: New York Zoological Society 148: 1 Turdus fumigatus Weight. Males: (18, 7 different) 64-75, 70.6. Females: (13, 7 different) 66.5-83, 75.6. Unsexed: (93, 66 different) 56.5-80.5, 70.9. Wing. Males: (5) 114-118, 116.0. Females: (5) 106-119, 112.4. Weights and measurements given above are for birds from the Northern Range of Trinidad. As mentioned earli- er, a few birds from the lowlands of central Trinidad were both lighter and shorter-winged — weights: males 55.5, 59.5; females 71.5, 72.5; unsexed 62; —wings: males 109, 114; females 104, 108; unsexed 108. Turdus nudigenis Weight. Males: (25) 55-74.5, 61.6. S.D. 4.6. Females: (9) 56.5-74, 65.6. 75 (egg- laying). Unsexed: (54, 50 different) 57.5-72, 64.7. 75; 79.5 (probably egg-laying fe- males). Wing. Males: (35) 104-122, 112.8. S.D. 3.9. Females: (14) 107-113, 109.4. Platycichla flavipes Weight. Female: 61.5. Ramphocaenus melanurus Weight. Female: 8. Unsexed: (9) 8.5-9.5, 9.2. Cyclarhis gujanensis Weight. Unsexed: (17, 11 different) 26-31.5, 28.8. Vireo olivaceus Weight. Unsexed: (8, 6 different) 14-16, 14.8. Hylophilus aurantiifrons Weight. Male: 8.5. Female: 8.5. Unsexed: 10; 10; 10; 10.5; 10.5. Chlorophanes spiza Weight. Adult males: (15, 14 different) 17.5- 19, 18.4. Unsexed (female plumage): (7) 16- 19.5, 17.9. Wing. Adult males: (11) 71-75, 73.2. Cyanerpes cyaneus Weight. Adult males: 13; 14.5, 15; 15. Unsexed (female plumage): (7) 12.5- 16, 13.9. Cyanerpes caeruleus Weight. Adult males: (8) 12-13.5, 12.5. Unsexed (female plumage): (6) 11.5- 12.5, 12.0. 14.5 (probably egg-laying female). Dacnis cayana Weight. Adult males: (6) 13-15, 13.8. Unsexed (female plumage): 12.5; 14; 14.5; 15; 15.5. Coereba flaveola Weight. Adult males: (34) 9-12, 10.5. S.D. 0.69. Immature males: 10; 10; 11.5. Adult females: (24) 9-11, 9.9. S.D. 0.64. 12.5; 13 (egg-laying). Immature females: (7) 9-11.5, 10.0. Unsexed adults: (176, 164 different) 8.5-12.5, 10.6. Wing. Adult males: (63) 54-61, 57.7. S.D. 1.4. Immature males: (8) 53-57, 55.1. Adult females: (48) 50-59, 54.2. S.D. 1.6. Immature females: (14) 49-55, 52.4. Parula pitiayumi Weight. Unsexed: 8.5. Dendroica petechia Weight. Males: Nov., 8.5; 9. Jan., 9. Feb., 9; 9; 9. Females: Nov., 7.5; 7.5; 9. Dec., 7.5. Jan., 8. Feb., 8. Dendroica striata Weight. Unsexed: Oct., 9 (on coast, probably recently arrived from oversea). Seiurus noveboracensis Weight. Males: Oct., 16.5; Nov., 17.5. Apr., 14.5; 16. Females: Oct., 15.5. Nov., 14; 14.5; 14.5. Dec., 16. Apr., 21. Unsexed: see Table VI. Wing. Males: (5) 75-79, 76.8. Females: (6) 71-75, 73.0. Geothlypis aequinoctialis Weight. Male: 14.5. Setophaga ruticilla Weight. Adult males: Oct., 8. Nov., 7; 7.5. Dec., 7.5. Jan., 7.5; 7.5; 8. Immature males: Nov., 7.5. Jan., 7. Females: Nov., 7.5. Feb., 7.5. Wing. Adult males: (5) 63-65, 64.2. Basileuterus culicivorus Weight. Unsexed: (10, 8 different) 9.5-11, 10.2. Molothrus bonariensis Weight. Males: 38.5; 39; 40.5. Females: 29.5; 29.5. Wing. Females: (9) 82-87, 85.0. Quiscalus lugubris Weight. Male: 76. Icterus nigrogularis Weight. Males: 49; 50. Females: 40.5; 44. Wing. Females: (6) 81-92, 87.4. Agelaius icterocephalus Weight. Males: (27) 31.5-40, 35.4. S.D. 2.0. Females: (17) 24-31, 26.6. Wing. Males: (25) 82-91, 87.0. S.D. 2.4. Females: (12) 70-81, 76.6. 1963] Snow & Snow: Weights and Wing-lengths of Some Trinidad Birds 1 i Table VI. Weights of Seiurus noveboracensis (All records, including sexed and unsexed birds) Weight (gm ) Month of capture i Oct. Nov. Dec. Jan. Feb. Mar. Apr. May 22 21 19.5 18.5 18 17.5 — 1 1 — — — 1 1 2 2 2 1 1 17 — 1 1 2 — — 1 — 16.5 2 2 2 1 1 — — — 16 — 1 2 — — — 1 — 15.5 1 1 2 2 — 1 — — 15 1 1 7 2 — — — — 14.5 14 13.5 — 6 3 1 1 — 1 — 1 13 1 — — — — — — — 12.5 — 1 — — — — — — Leistes militaris Weight. Unsexed ( female plumage ): 38.5. Tanagra violacea Weight. Adult Males: (37, 30 different) 12.5- 16.5, 14.5. S.D. 0.91. Females: (6, 4 different) 13.5-16, 14.8. Unsexed (female plumage): (15, 12 different) 13-15.5, 14.3. 17 (probably egg-laying female). Wing. Adult Males: (24) 56-62, 58.5. S.D. 1.8. Females: (5) 54-57, 55.4. Tangara chrysophrys Weight. Unsexed: (8, 7 different) 17-20.5, 18.4. Tangara mexicana Weight. Females: 20.5; 21. Unsexed: (11) 18-23.5, 20.9. Tangara gyrola Weight. Unsexed: (46, 43 different) 18-24, 20.7. Thraupis virens Weight. Male: 33.5. Female: 35. Unsexed: (28, 24 different) 31-42.5, 37.1. Wing. Males: (5) 89-96, 91.8. Females: (10) 85-92, 88.0. Thraupis palmarum Weight. Males: 35; 35.5; 36.5; 37. Females: 35.5; 37.5; 38. Unsexed: (32, 29 different) 32-42.5, 38.6. Wing. Males: (9) 95-98, 96.4. Females: (6) 87-95, 91.3. Ramphocelus carbo Weight. Adult males: (111, 83 different) 24.5- 37.5, 29.5. S.D. 2.2. Immature males: (17) 25-29.5, 27.5 Females: (23) 23.5-31, 27.4. S.D. 2.1. 33 (egg-laying). Unsexed (female plumage): (63, 53 dif- ferent) 24-31.5, 27.8. Wing. Adult males: (87) 76-85, 80.9. S.D. 1.8. Immature males: (22) 74-83, 79.2. S.D. 2.3. Females: (43) 72-80, 77.1. S.D. 1.8. Habia rubica Weight. Adult males: (19, 11 different) 29.5- 35.5, 31.7. Immature males: 27.5; 31.5. Unsexed (female plumage): 26.5; 30.5; 32.5; 32.5; 37 (probably egg-laying female). Wing. Adult males: (9) 88-93, 90.7. Tachyphonus rufus Weight. Adult males: (36, 31 different) 31-40.5, 34.9. S.D. 1.9. Females: (16, 8 different) 33.5-42.5, 37.5. 47.5 (probably egg-laying). Juveniles: (6) 30.5-35, 33.4. Wing. Adult males: (34) 82-92. 87.5. S.D. 2.2. Females: (7) 81-88, 84.7. Tachyphonus luctuosus Weight. Adult males: (8, 5 different) 12.5-15, 13.6. Females: 13, 13.5; 17.5 (probably egg- laying). Saltator albicollis Weight. Unsexed: (10) 33-40.5, 37.5. 12 Zoologica: New York Zoological Society [48: 1: 1963] Saltator caerulescens Weight. Males: 48.5; 51.5; 52.5; 53. Unsexed: 51; 52; 53.5; 54. Tiaris bicolor Weight. Adult male: 8.5. Unsexed ( female plumage): 8; 9. Tiaris fuliginosa Weight. Adult males: (11, 9 different) 11-16, 13.3. Females: 13; 13; 13; 14. Unsexed (female plumage): (9) 12.5- 14, 13.3. Wing. Adult males: (13) 58-63, 59.7. Sporophila intermedia Weight. Adult males: 11; 13. Immature males: 11; 11.5; 11.5; 13; 13. Females: 11; 11.5; 11.5; 13. Unsexed (female plumage): (7) 11.5- 14, 12.4. Wing. Males: (8) 54-57, 55.3. Females: (8) 52-56, 53.9. Sporophila nigricollis Weight. Adult males: 9; 9.5. Sporophila lineola Weight. Adult males: (11) 7.5-12, 9.8. Immature males: 8; 9; 9; 9. Females: 8.5; 8.5. Unsexed (female plumage): (13) 9-11, 9.9. Juveniles: (6) 8. 5-9. 5, 8.9. Wing. Adult males: (10) 55-59, 57.3. Immature males: (6) 54-57, 55.2. Sporophila minuta Weight. Adult males: (10) 7-9, 7.9. Immature males: 7; 7; 7.5; 8. Females: 7; 7; 8; 8; 8. Unsexed (female plumage): 7.5; 7.5; 8; 8.5. Wing. Adult males: (28) 47-51, 48.8. S.D. 1.1. Females: (13) 46-50, 48.2. Oryzoborus angolensis Weight. Immature male: 14.5. Unsexed (female plumage): 12.5; 12.5. Volatinia jacarina Weight. Adult males: (25) 8.5-11.5, 9.7. S.D. 0.70. Immature male: 11.5. Females: 9; 10; 10; 10.5. Unsexed (female plumage): (12) 8-12, 9.5. Wing. Adult males: (37) 45-51, 48.3. S.D. 1.3. Females: (9) 45-48, 46.4. Summary Over 4,000 bird weights from Trinidad are summarized. Individual variation and diurnal and seasonal weight changes are discussed. Two species for which there were large samples were found to show a slight increase in weight in the course of the day. Females were found to aver- age slightly heavier during the breeding season than at other times of year. Males showed no ap- preciable seasonal variation except for a tend- ency towards an increase in weight during the moult. Local variation within Trinidad was de- tected in a few species. Literature Cited Amadon, D. 1943. Bird weights as an aid in taxonomy. Wil- son Bull., 55: 164-177. Haverschmidt, F. 1948. Bird weights from Surinam. Wilson Bull., 60: 230-239. 1952. More bird weights from Surinam. Wilson Bull., 64: 234-241. Junge, G. C. A., & G. F. Mees 1958. The avifauna of Trinidad and Tobago. Zool. Verhand. (Leiden), No. 37. Pp. 172. Snow, D. W. 1962a. A field study of the Black and White Man- akin, Manacus manacus, in Trinidad. Zoologica, 47 (8): 65-104. 1962b. Notes on the biology of Trinidad swifts. Zoologica, 47 (12): 129-139. Appendix [This paper is one of a series emanating from the Tropical Field Station of the New York Zoological Society, at Simla, Arima Valley, Trinidad, West Indies. This station was founded in 1950 by the Zoological Society’s Department of Tropical Re- search, under the direction of Dr. William Beebe. It comprises 200 acres in the middle of the Northern Range, which includes large stretches of undis- turbed government forest preserves. The laboratory of the Station is intended for research in tropical ecology and in animal behavior. The altitude of the research area is 500 to 1,800 feet, and the annual rainfall is more than 100 inches. [For further ecological details of meteorology and biotic zones, see “Introduction to the Ecology of the Arima Valley, Trinidad, B.W.I.,” William Beebe, Zoologica, 1952, 37 (13): 157-184.] 2 The Reproductive Behavior of the Green Sunfish, Lepomis cyanellus 1 John R. Hunter Hydrobiology Laboratory, Department of Zoology, University of Wisconsin 2 (Text-figures 1-7) Introduction THAT the gonads of many centrarchids mature at intervals during the breeding season and that a population of centrar- chids may have more than one breeding period during a season is known (Breder, 1936, 1940; James, 1946; and Kramer & Smith, 1962). No complete record, however, has been kept of the nesting habits of a population of sunfish through- out a breeding season. In addition, there is no published account of the reproductive behavior of the green sunfish although there are many descriptions of the breeding habits of other cen- trarchids (Breder, 1936). The present study contributes information on the reproductive behavior of the green sunfish, Lepomis cyanellus (Rafinesque). Particular em- phasis is placed on the frequency of nest con- struction by male green sunfish. Procedures During two spawning seasons observations were made of green sunfish in four of the Gard- ner Ponds of the University of Wisconsin Ar- boretum. Ponds D and E were the largest. They were roughly rectangular in shape, had an area of approximately 2,023 sq. meters, a maximum depth of approximately 2 meters and were separated by a cinder dam. The cinders com- 1Based on part of a doctoral dissertation submitted to the faculty of the Graduate School, University of Wisconsin. This study, under Dr. Arthur D. Hasler, was sup- ported in part by grants from the National Science Foundation and the Wisconsin Conservation Depart- ment. Contributions from the University of Wisconsin Ar- boretum, No. 52. 2Current address, Bureau of Commercial Fisheries, San Diego, California. prised the only firm substratum in the ponds. These ponds supported a large population of green sunfish, northern redfin shiners ( Notropis umbratilis cyanocephalus) , northern black bull heads ( Ictalurus melas melas ) and brook stickle- backs ( Eucalia inconstans) . The two smaller ponds, designated as Theta and Delta, were also rectangular in shape, had an area of approximately 5 sq. meters and a maximum depth of 1 to 1 .5 meters. Pond Delta supported a small population of green sunfish. There were no fish in Pond Theta until the Spring of 1961 at which time four male and six female green sunfish were stocked in it. Unlike the larger ponds, there was no firm substratum along the entire margin of these smaller ponds. An artificial spawning substrate was provided for the fish in Ponds Theta and Delta by placing a 1 -meter-square box filled with cinders at the north and south ends of each. The spawning grounds of Ponds D and E in 1960 and Ponds E, Delta and Theta in 1961 were visited each day during the breeding sea- son. Each sunfish nest constructed on the spawn- ing grounds was marked, described and the pro- tocol recorded. Included in this account was the location of the nest, the time of construction, the duration of occupation and the time of desertion. A thermograph recorded the water temperature of the spawning grounds of Pond E during the entire spawning season. Daily maximum and minimum water temperatures of the two small ponds (Theta and Delta) were taken during the same period. Male green sunfish in Pond Theta and Pond E were tagged at the beginning of the 1961 sea- son and daily records were made of their nesting habits. In order to determine the factors in- 13 14 Zoologica: New York Zoological Society [48: 2 volved in the recognition of the nest site by the male green sunfish, field experiments were per- formed. Results Sexual Dimorphism and Nest Construction.— During the breeding season a lateral series of dark vertical bars distinguished the female green sunfish from the male. This color phase was the same as that assumed by all green sunfish when extremely frightened. Males were more bril- liantly colored and were larger than females. In addition, mature males possessed a prominent yellowish white line along the margin of the dorsal, caudal and anal fins. The white lines appeared on large males about a week before the first period of nest establishment; small males matured at a later date. Male green sunfish constructed their nests in a manner characteristic of members of the fam- ily Centrarchidae. The male would rise ver- tically above the nest site and deliver a burst of vigorous outward thrusts with its tail. Each series of thrusts displaced some sand and gravel and gradually a shallow depression was formed. A male might spawn and dig in this fashion for one or two days, but after completion of the spawning period digging usually ceased. Male green sunfish in the Gardner Ponds nearly always used the cinder and gravel areas to construct their nests and only rarely con- structed nests along the muck margins. When a muck substrate was used, the male dug a deep nest, exposing the underlying marl. The nests most commonly occurred in unshaded areas which received a maximum duration of sun- shine. The nests were constructed in shallow water seldom deeper than 35 cm.; small males constructed nests in water as shallow as 4 cm. If available, areas sheltered by rocks, logs and clumps of grass were nearly always used for nest sites. Occasionally, abandoned sunfish nests were used by a male green sunfish as a site for a new nest, particularly if the nest was large and deep. I induced males to colonize new areas of the spawning grounds by scooping out depres- sions in the gravel which were deeper and larger than those they themselves constructed. These artificial nests were used throughout the spawn- ing season. A day or two in advance of nest establishment green sunfish congregated near the spawning grounds. In the beginning these aggregations were composed primarily of large males but as nests were established and spawning com- menced, the area became congested with females and males of all sizes. When males commenced spawning many females and non-nesting males assembled near the nest. The largest concentrations were formed around the periphery of the nests of the first males that spawned. In Pond E, which had a large population, I counted 114 sunfish as- sembled near the nest of a spawning male. Such spawning aggregations were visited, at one time or another, by most of the non-nesting males on the spawning grounds. Eventually some of the males in the congregation commenced dig- ging nests in the vicinity of the original nest and a colony of nesting sunfish was established. As colonization began, the number of fish around individual nests decreased and became com- posed primarily of females. Territorial Behavior— Nearly all centrarchid males exhibit territorial behavior while they are occupying a nest. Witt & Marzolf (1954) re- ported that male long-ear sunfish, Lepomis megalotis megalotis, defended larger territories when their nests were isolated than when the nests were a part of a colony. I drew similar conclusions from my observations of nesting green sunfish. Within the colonies of Pond E, where nests were often less than 2 cm. apart, the males defended only the area encompassed by the nest. In Pond Theta, on the other hand, the distance between nests was as great as 30 meters and the males defended an area 1 to 1.5 meters in diameter. Sunfish collected around the nests of spawning males in Pond Theta but were not as close to the nests as they were in Pond E. Fighting between males in the small ponds was never observed, but combat between male sunfish often took place on the crowded spawn- ing grounds of the large ponds. The two male combatants pressed their open mouths to their opponent’s operculum and, in this position, they rotated (Text-fig. 1). Only when the males were engaged in constructing nests and spawning did fighting occur, although they could be artificially induced to fight at other times. When I covered the nests of two males with stones in such a manner that their territories overlapped, a battle ensued. Prior to spawning, nesting males sometimes permitted another male to swim through the nest or they ejected the male merely by nipping. As soon as the male commenced to spawn, he responded very aggressively to such intrusions and, with opercula spread wide, vigorously drove the trespassing fish from the nest. During spawning periods male green sunfish were more active than during any other segment of their reproductive cycle. When a male was not engaged in spawning or chasing intruding fish he was usually swimming in circles inside the nest and taking frequent brief excursions 1963] Hunter: Reproductive Behavior of Lepomis cyanellus 15 Text-fig. 1. Fighting posture of two male Lepomis cyanellus. outside. A male often punctuated his trips out- side by nipping or threatening sunfish which were nearby. I observed one male during a ten- minute period execute five spawning acts, make ten trips in and out of the nest, threaten his neighbor once and gyrate in the nest 39 times. Spawning Behavior.— If females were present on the spawning grounds, males usually com- menced spawning on the day they constructed their nests or on the following day. If no females were present a male might continue to occupy his nest intermittently for as long as a week. The spawning period of a male sunfish occa- sionally extended over three or four successive days but usually was restricted to one or two. Spawning was accomplished in the manner typi- cal of all centrarchids: the male and female circled in the nest side by side, paused momen- tarily and released sperm and eggs. The con- summatory act took place when the female re- clined on her side and vibrated while the male remained in an upright position. An isolated pair might circle and spawn in a nest for con- siderable periods of time but in crowded colonies the male frequently interrupted spawning to chase intruding fish. After spawning, the male expelled the female from the nest with a nip. Both sexes usually spawned with more than one individual. Occasionally a male spawned simul- taneously with more than one female. While a pair of sunfish were circling in the nest an- other female entered the nest, aligned itself with the male, and when the first female rotated on her side the intruding female also slid beneath the male and vibrated. Green sunfish did not spawn after dark but the aggregations of females and non-nesting males, along with the nesting males, remained on the spawning grounds overnight during spawning periods. Once spawning commenced, rain and thun- derstorms did not seem to curtail mating. I ob- served sunfish spawning on cloudy days and during thundershowers. This observation differs markedly from that made by Breder (1936) on the pumpkinseed, Lepomis gibbosus. He noticed that this species was so sensitive to changes in illumination it retreated to deep water during the passage of a cloud over the sun. I never saw green sunfish respond to clouds in this manner. Sexual Recognition. — In connection with studies on the behavior of Notropis umbratilis (in preparation) a realistically painted latex sunfish model, cast from a mold of a male sun- fish, was placed in various regions of the spawn- ing grounds. The model was rotated in a circle (30 cm. diameter) at a speed of 6 rpm. by means of a small electric motor located in a sub- merged plastic case. Occasionally a few male or female sunfish assembled near the model. In one case, after threatening the model, a male commenced to circle with it in a manner which suggested spawning. The male interrupted his circling to chase away intruders and to execute a series of rapid digging movements near the model. This suggests that the circling of a female in a nest may be one of the stimuli by which a male recognizes a female. That sex recognition on the part of the male is based on the behavior of the female green sunfish seems likely as the male does not appear to distinguish between males and females when they are outside of the nest. The approach of the female was nearly al- ways hindered, rather than facilitated, by the male green sunfish. Any fish near the nest was threatened, sometimes nipped, but a female, un- like a male, continued to approach. As the female swam up to the side of the male they began to circle slowly and spawning commenced. The presence of a male appeared to be suffi- cient stimulus to cause a female to enter a nest. Female green sunfish attempted to mate with nesting males in all phases of the male’s re- productive cycle. During the latter part of the nesting period I occasionally saw females move from nest to nest in old sunfish colonies, often being expelled from every nest. Females some- 16 Zoologica: New York Zoological Society [48: 2 times darted beneath a male, immediately ro- tated on their sides and vibrated. Sometimes mating was accomplished in this fashion but often the male remained sexually passive, in which case the female was eventually driven from the nest. Females were most strongly attracted to and at- tempted to mate most often with males that had already started to spawn. As I have mentioned, spawning males, and perhaps unmated males excited by spawning males, behaved in a unique fashion. They gyrated rapidly and made fre- quent trips in and out of the nest. It may be that these additional activities made the spawning males more attractive to females. Breder (1936) believes that the gyrations of a male sunfish over a depression are the stimulus to which the females respond. I suspect that odors which may be released during the spawning act might also play a role in the attraction of females to the nests of spawning male green sunfish. Breeding Cycles.— The breeding season of the green sunfish in the Gardner Ponds commenced in late May or early June, continued through June and July and terminated in early August. Daily tabulations of the number of nests con- structed in Ponds E and Delta revealed that most nests were constructed during definite periods (Text-figs. 2, 3 and 4). The average frequency of the periods of nest establishment was every eight days in Pond E during the 1960 season and nine days in Ponds E and Delta during the 1961 breeding season. Since male green sunfish commenced spawning during the first or second day of occupancy, the periods of nest establishment coincided with periods of in- tense spawning. In 1961, sunfish in Pond Delta (Text-fig. 4) commenced constructing nests three days later than the fish in Pond E (Text-fig. 3) and as a result the periods of nest construction of the two populations were out of phase. However, the nesting periods in the two ponds gradually came into phase and, by the seventh period, the day of maximum nest construction occurred on the same day. The daily mean water temperature for Pond E and the percentage of possible sunshine are shown in Text-figs. 2 and 3. The latter data were obtained from the U.S. Department of Commerce Weather Bureau at Truax Field, Madison. There appears to be no relationship between the daily amount of sunshine and the occurrence of nesting periods. Field observa- tions support this view; large numbers of green sunfish were observed constructing their nests and spawning on overcast as well as on sunny days. There does, however, appear to be a cor- respondence between water temperature and nesting periods. The peak of each period of nest establishment nearly always coincided with a rise in the mean water temperature. In Pond 1 v> 2 3 V> * a. 2 UJ flc UJ H* Vz to 4 inches stretched. In one hour the fishermen began pulling in the net. They found it to be full of bonnethead sharks, Sphyrna tiburo (Linnaeus), which lo- cally is called “shovelnose shark,” distinguishing it from any of the other hammerheads. Mr. Stanley estimates that well over 700 sharks were gilled and it took the two men six hours to re- move them. The hands of the men were sore and raw from handling the sharks even though they were practically all dead and hardly moved when handled. The sharks were between 2 and 3 feet long. Unfortunately none were saved. Three other unidentified sharks about 3 feet long and of a typical Carcharhinus body shape were tangled in the net along with 300 pounds of mackerel weighing about IV2 pounds each. The fishermen were disgusted with their poor catch but a few days later thought to report it to us. Mr. Stanley, who has been a local commercial fisherman for over forty years, regularly has seen, at least once or twice each year, schools of bonnethead sharks comprised of about 50 to 75 individuals. He informs me that large schools of bonnethead sharks, comprised of hundreds of individuals, were not uncommon before the severe “blooms” of Gymnodinium brevis (“red tide”) in 1946-47. These large schools of sharks occurred often enough, though at no particular time of year he can recall, so that mackerel fishermen were cautious to inspect carefully what appeared to be a large school of mackerel, in order to avoid netting a mass of these sharks. Since 1946-47, however, this caution was re- laxed as large schools of sharks no longer were seen until the present case reported above. Summary Two exceptionally large aggregations of elasmobranchs are reported from shallow water on the Gulf Coast of Florida at Sarasota. Rays, probably Rhinoptera bonasus, were photo- graphed from a plane at New Pass in July, 1 959. A study of the photograph reveals about 4,000 to 6,000 individuals in school-like formation. Over 700 bonnethead sharks, Sphyrna tiburo, were caught by commercial fishermen in a gill net near Lido Key in November, 1962. Observa- tions of other aggregations or schools of these species are reviewed. Acknowledgements I wish to thank James W. Atz, Charles M. Breder, Jr., and Stewart Springer for comments on this manuscript. Literature Cit Bigelow, H. B., & W. C. Schroeder 1953. Fishes of the Western North Atlantic. Part Two. Sears Foundation for Marine Research, New Haven, Conn., 558 pp. illus. 64 Zoologica: New York Zoological Society [48: 6: 1963] Breder, Jr., C. M. 1959. Studies on social groupings in fishes. Bull. Amer. Mus. Nat. Hist. 117 (6): 397-481. Coles, Russell J. 1910. Observations on the habits and distribu- tion of certain fishes taken on the coast of North Carolina. Bull. Amer. Mus. Nat. Hist. 28(28): 337-348. Springer, Victor G., & Kenneth D. Woodburn 1960. An ecological study of the fishes of the Tampa Bay area. Professional Papers Ser- ies (1), Fla. State Bd. Conservation Ma- rine Lab. EXPLANATION OF THE PLATES Plate I Plate II Fig. 1. Aerial photograph of a dense aggregation Fig. 2. Enlargement of a central area of the school of rays, probably Rhinoptera bonasus of rays. (Mitchill), in Big Pass, Sarasota, from a height of approximately 300 feet. (Lionel Murphy, photographer) CLARK PLATE I MASSIVE AGGREGATIONS OF LARGE RAYS AND SHARKS IN AND NEAR SARASOTA. FLORIDA CLARK PLATE II MASSIVE AGGREGATIONS OF LARGE RAYS AND SHARKS IN AND NEAR SARASOTA. FLORIDA NEW YORK ZOOLOGICAL SOCIETY GENERAL OFFICE 630 Fifth Avenue, New York 20, N. Y. PUBLICATION OFFICE The Zoological Park, Bronx 60, N. Y. OFFICERS PRESIDENT VICE-PRESIDENT SECRETARY TREASURER Fairfield Osborn Laurance S. Rockefeller George W. Merck David H. McAlpin SCIENTIFIC STAFF: William G. Conway. . Director, Zoological Park Christopher W. Coates. .Director, Aquarium John Tee-Van General Director Emeritus ZOOLOGICAL PARK Joseph A. Davis, Jr. . . Curator, Mammals Grace D avail Assistant Curator, Mammals and Birds William G. Conway. . Curator, Birds Joseph Bell Acting Assistant Curator, Birds Herndon G. Dowling . Curator, Reptiles Charles P. Gandal. . . Veterinarian Lee S. Crandall General Curator Emeritus Roland Lindemann .... Consultant in Mam- mal Management AQUARIUM Paul Montreuil Curator Carleton Ray Associate Curator Ross F. Nigrelli Pathologist & Chair- man of Department of Marine Biochem- istry & Ecology Klaus D. Kallman. . . .Geneticist C. M. Breder, Jr Research Associate in Ichthyology Harry A. Charipper. . . Research Associate in Histology Sophie Jakowska Research Associate in Experimental Biology Louis Mowbray ..... Research Associate in Field Biology GENERAL William Bridges . . Editor & Curator, Publications Dorothy Reville . . Editorial Assistant Sam Dunton Photographer Henry M. Lester . . Photographic Consultant DEPARTMENT OF TROPICAL RESEARCH Jocelyn Crane Director Associates: Jane van Z. Brower William K. Gregory Lincoln P. Brower Donald R. Griffin William G. Conway David W. Snow Julie C. Emsley John Tee-Van Michael G. Emsley AFFILIATE L. Floyd Clarke Director, Jackson Hole Biological Research Station EDITORIAL COMMITTEE Fairfield Osborn, Chairman William Bridges Lee S. Crandall Christopher W. Coates Herndon G. Dowling William G. Conway Si 6,S 13 ZOOLOGICA SCIENTIFIC CONTRIBUTIONS OF THE NEW YORK ZOOLOGICAL SOCIETY VOLUME 48 • ISSUE 3 • FALL, 1963 PUBLISHED BY THE SOCIETY The ZOOLOGICAL PARK, New York Contents PAGE 7. Experimental Studies of Mimicry. 7. Relative Palatability and Mullerian Mimicry among Neotropical Butterflies of the Subfamily Heliconiinae. By Lincoln Pierson Brower, Jane Van Zandt Brower & Charles T. Collins. Plate 1 65 8. A Morphological Study of Imagine Heliconiinae (Lep.: Nymphalidae) with a Consideration of the Evolutionary Relationships within the Group. By Michael Emsley. Plate I; Maps 1-17; Text-figures 1-153 85 9. Spontaneous Tuberculosis in Fishes and in Other Cold-blooded Verte- brates with Special Reference to Mycobacterium fortuitum Cruz from Fish and Human Lesions. By Ross F. Nigrelli & Henry Vogel. Plates I- VI. . 131 Zoologica is published quarterly by the New York Zoological Society at the New York Zoological Park, Bronx Park, Bronx, N. Y. 10460, and manuscripts, subscriptions, orders for back issues and changes of address should be sent to that address. Subscription rates: $6.00 per year; single numbers. $1.50, unless otherwise stated in the Society’s catalog of publications. Second-class postage paid at Bronx, N. Y. Volume 48, Issue 2 (Summer, 1963) was published on August 22, 1963 7 Experimental Studies of Mimicry. 7. Relative Palatability and Mullerian Mimicry among Neotropical Butterflies of the Subfamily Heliconiinae1,2 Lincoln Pierson Brower, Jane Van Zandt Brower & Charles T. Collins* * 3 Biology Laboratory, Amherst College, Amherst, Massachusetts (Plate I) [This paper is a contribution from the William Beebe Tropical Research Station of the New York Zoological Society at Simla, Arima Valley, Trinidad, West Indies. The Station was founded in 1950 by the Zoological Society’s Department of Tropical Re- search, under Dr. Beebe’s direction. It comprises 200 acres in the middle of the Northern Range, which includes large stretches of government forest re- serves. The altitude of the research area is 500 to 1,800 feet, with an annual rainfall of more than 100 inches. [For further ecological details of meteorology and biotic zones see “Introduction to the Ecology of the Arima Valley, Trinidad, B.W.I.,” by William Beebe, Zoologica, 1952, Vol. 37, No. 13, pp. 157-184], Contents Page I. Introduction 65 II. Acknowledgments 67 III. Materials and Methods 67 IV. Experimental Design 68 V. Results and Discussion 69 A. General Unpalatability of Heliconiine Butterflies 69 B. Specific Differences in Palatability... 70 C. Phylogenetic Relationships and Palatability 72 D. Mullerian mimicry 73 E. Evidence that Mullerian Mimicry Operates in Nature 74 1. Treatment of First Models 74 2. Treatment of Generalization Butterflies 76 F. Evidence that a Generalized Resem- blance Confers a Mimetic Advantage. 78 VI. Summary 80 VII. References 80 department of Tropical Research Contribution No. 1040. Supported by National Science Foundation grants G-6376 and G-20152 (see acknowledgments). 3Present address: Department of Biology, University of Florida, Gainesville, Florida. I. Introduction THE choice of the Heliconiinae for this in- vestigation is not without historical basis, for it was observations of these and other Neotropical butterflies that led naturalists in the latter half of the 19th century to formulate the theories known as Batesian and Mullerian mim- icry. According to the theory of Bates (1862), rare palatable species, called the mimics, have gradually evolved through natural selection to resemble common unpalatable species, the mod- els, of widely distinct taxonomic groups. This is brought about through the action of predators which, after trying a model insect, learn to asso- ciate its color-pattern with its noxious quality and so come to refuse it on sight. They then tend to confuse with the model and reject those naturally occurring variants in the palatable species which bear a resemblance to it. The early history and evidence for this phenomenon in many groups of insects and some vertebrates have been summarized by Carpenter & Ford (1933). Additional indirect support for the theory of Batesian mimicry has been accumu- lated over the years (Carpenter, 1920, 1949; Sheppard, 1959; Brower & Brower, 1962b), and it has been demonstrated in laboratory experi- ments for butterflies (Brower, J., 1958 a, b, c), artificial mimics (Muhlmann, 1934; Schmidt, 1958; Sexton, 1960; J. Brower, 1960) and flies (Mostler, 1935; Brower, Brower & Westcott, 1960; Brower & Brower, 1962a), with the use of toads, lizards and a variety of birds as caged predators. Further light has been shed upon the evolution of mimicry by the genetical studies of Ford (see review, 1953), Sheppard (1961, 65 66 Zoologica: New York Zoological Society [48: 7 1963), Clarke & Sheppard (1960, 1962) and Turner & Crane (1962). However, it was clear even to Bates (1862) that resemblances also existed among species belonging to what he assumed to be one large distasteful family. Because his hypothesis re- quired that mimicry occur between members of unrelated groups, he concluded that the likeness in these instances was due not to the adaptation of one to the other, but to the similar adaptation of all to the same local, probably inorganic, conditions. Wallace (1871) was also puzzled by the resemblances among related butterflies and suggested that the “distasteful secretion is not produced alike by all members of the family, and that where it is deficient, protective imita- tion comes into play” (p. 85). This statement was of the utmost importance because it initiated the idea of varying degrees of unpalatability within a group and in addition anticipated the line of reasoning later developed by Muller (1879). He, too, had had experience in the Neotropics, and from his observations on two butterflies, Thyridia and Ituna, arrived at a new hypothesis. Because of their similar appearance, these two genera had until that time been lumped in the family Danaidae. On several morphological bases, Muller separated them, leaving Ituna with the Danaidae but placing Thyridia with the Ithomiidae. He then realized that these two butterflies which superficially re- sembled each other both belonged to supposedly distasteful families. In addition species in the one genus sometimes outnumbered those in the other and vice versa in the natural environment. These facts did not meet the conditions of mimicry in the Batesian sense where one member of a similar pair is palatable and rare. Muller rea- soned that if each predator has to learn the dis- tinction between unpalatable and palatable spe- cies, then a certain number of individuals of both must fall victim to the inexperience of young enemies. But if two unpalatable species are sufficiently alike to be confused by predators, a lesson learned on one will also benefit the other. Thus the two will tend to converge upon a common color-pattern through selection by their insectivorous enemies, resulting in Miiller- ian mimicry. The evolution of the convergence was at first misunderstood, as evidenced by the arguments which the Mullerian hypothesis generated over the selective advantage of mimicry to the more and less numerous members of an unpalatable complex. Marshall (1908) held that if species A outnumbered species B, B could evolve towards A but the reverse would not occur be- cause any mutant of A that resembled B would be selected against by predators. Dixey (1908) countered this by saying that any mutant which was intermediate between A and B would gain the full advantage of both, and the two species would converge upon a mutual color-pattern. Fisher (1927, 1930 and 1958) pointed out the fallacies in both arguments by showing that while the less frequent species would derive the greater advantage, nevertheless the more abun- dant one would gain slightly by the pooled re- semblance. The result would be a tendency for the two to converge upon a mutual color-pattern, but at unequal rates. Thus even a very rare unpalatable species does contribute to the over- all effectiveness of Mullerian mimicry, is not detrimental to the common member, and should be considered a functional part of the complex. Fisher’s clarification of this has been overlooked in some important papers on Mullerian mimicry (Darlington, 1938; Linsley, Eisner & Klots, 1961). Huheey (1961) has opened a new and very promising aspect of the problem in a dis- cussion of the possible evolution of a Mullerian situation from a Batesian one. But in spite of the voluminous literature on the natural history and the theoretical implica- tions of Mullerian mimicry, very little experi- mental evidence has been produced, as was the case with Batesian mimicry until recently. The occurrence of potential models or Mullerian mimics in butterflies has been inferred the world over wherever their larvae eat the so-called poisonous foodplants, for example, those of the families Asclepiadaceae (milkweeds), Asara- ceae (birthworts) and certain of the Solanaceae (nightshades). However, this correlation does not always hold, since species of the Passiflor- aceae (passion flowers) are foodplants of the heliconiines (Alexander, 1961a) and these are generally not cited as being poisonous (Muen- scher, 1939). The early contributions discussing systematics and Mullerian mimicry in the heli- coniines include Muller (1877), Dixey (1897), Stichei & Riffarth (1905), Kaye (1906, 1916), Moulton (1908), Seitz (1913) and Eltringham (1916). Numerous further instances commonly cited as Mullerian mimicry occur in the Hemip- tera, Coleoptera and various families of moths. In these, there is a widespread repetition of orange or red and black coloration, together with the possession of noxious body fluids or defensive glands, and in the Hymenoptera there is, for example, the frequent occurrence of yel- low and black circular banding associated with a stinging apparatus. (See Nicholson, 1927, and Linsley, 1959, for valuable summaries). Some experimental evidence for the unpalatability and mimicry of beetles of the family Lycidae has been obtained by Carpenter (1921) in Africa 1963] Brower , Brower & Collins: Experimental Studies of Mimicry 67 with monkeys, Cercopithecus sp., as predators, by Darlington (1938) in Cuba with lizards, Anolis sagrei (Dumeril & Bibron), and by Linsley, Eisner & Klots (1961) in Arizona with a variety of vertebrates and invertebrates. The only evidence on palatability for the heliconiines (“Heliconii”) known to us is that obtained by Belt (1874, p. 242). He noted that a pair of birds bringing butterflies and dragonflies to their young never included these “Heliconii” which were extremely common in the area and he also showed that they were unpalatable to a tame White-faced Monkey ( Cebus sp.) . The purpose of this paper is to present the results of an experiment designed to ask the following basic questions about Mullerian mim- icry in the classical heliconiine butterflies: (A), Are these insects unpalatable to bird predators? (B), Do differences in unpalatability exist? (C), If so, do they correspond to the phylogenetic relationships of the butterflies? (D), Are heli- coniine butterflies which resemble each other effective Mullerian mimics? In addition the ex- periment provided unanticipated evidence bear- ing on two further important aspects of mimicry theory. Framed as questions, these are (E), Do wild-caught birds behave in the laboratory in such a way as to suggest prior experience with Mullerian mimics in nature? and (F), Do birds generalize with regard to color, pattern or shape of the butterflies by transferring their learned re- jection of a model to another heliconiine unlike the model-mimic pair? II. Acknowledgments This correlated laboratory and field experi- ment was carried out during the summers of 1961 and 1962 at Simla, the William Beebe Tropical Research Station of the New York Zoological Society in the Arima Valley of Trin- idad, W.I. Our thanks are extended to the lab- oratory assistants at Simla, Mesdames Susan Allan, Kathleen Campbell, Julie C. Emsley, Jessie Lai-Fook Hsu and Thomasina Lai-Fook, for their vast effort in rearing and preparing the butterflies, for help in familiarizing us with the environment, and for assistance in capturing the birds. We are especially grateful to Jocelyn Crane and the late Dr. William Beebe of the New York Zoological Society for facilitating the research in every possible way. Thanks are also due Dr. E. B. Ford, F. R. S., of Oxford University, Dr. P. M. Sheppard of the Univer- sity of Liverpool and Dr. E. G. Linsley of the University of California for reading the manu- script and offering helpful suggestions. Dr. John Pryor of the University of Pennsylvania gave us useful advice on statistical analysis. We also wish to thank Mr. Malcolm Barcant of Port of Spain for helping us locate excellent collecting areas. To Lee Boltin of New York City, thanks are due for advice on the color plate photog- raphy. Thomas E. Pliske and F. Gary Stiles aided in collecting the birds, as did Jonathan Reiskind, who also assisted in conducting the experiments. The program was generously sup- ported by the following research grants from the United States National Science Foundation: during 1961: N.S.F. G-6376; New York Zoo- logical Society, grantee; Jocelyn Crane, princi- pal investigator; during 1962: N.S.F. G-20152; Amherst College, grantee; Lincoln P. Brower, principal investigator. Pliske, Reiskind and Stiles were aided by Genetics Training Grant No. 2G- 306-C2 from the U. S. National Institutes of Health. III. Materials and Methods Eight species of Heliconiinae consisting of four visually similar pairs, Heliconius erato hydara Hewitson and Heliconius melpomene euryades Riffarth; Heliconius numata ethilla Godart and Heliconius Isabella isabella (Cramer); Heliconius doris doris (Linnaeus) and Heliconius sara thamar Hubner; Dryas iulia iulia (Fabricius) and Agraulis vanillae vanillae (Linnaeus) were tested for relative palatability and Mullerian mimicry (Plate I). All (except H. isabella) were reared in the laboratory and only males were used as test insects. The adults were killed by deep-freezing after they had aged for two days in an out-door flight cage (or shortly after capture in the wild for H. isabella) . They were then thawed for a few minutes and placed with the wings spread in an open position in individual cellophane or glassine envelopes and kept in the deep freezer until used. This was done to alleviate the uncertainties of obtaining sufficient quantities of the needed species at the time the experiments had to be conducted. The freezing method also assured that the specimens were fresh and in a uniform state of preserva- tion. Miriam Rothschild (in lift., April 19, 1963) has pointed out that acetylcholine, which is found concentrated in certain distasteful insects, is inactivated by freezing. According to her, “the function of acetylcholine is not understood but there can be no doubt I think that it plays some part in enhancing the effect of poisons or harmful substances.” Whether or not it will be found in quantity in the heliconiines remains to be discovered, but it should be emphasized here that the comparative palatability findings presented in this paper, based on individual butterflies which had been frozen, may be sub- ject to some revision in the light of future work in the field of palatability biochemistry. 68 Zoologica: New York Zoological Society [48: 7 Care was taken to prevent desiccation of the insects while kept in the deep-freeze; wet towel- ing was placed in the freezer box (beneath and on top of wire screening in such a way as not to make contact with the butterflies) and the box was sealed with Scotch masking tape. Some of the butterflies reared and frozen in the spring of 1961, were used in the summer of 1962, as well as in 1961; the rest used in 1962 were preserved in the spring or summer of 1962. Butterflies used as edibles (see below) belonged to the family Satyridae and included various species of the genus Euptychia which were rea- sonably uniform in size and appearance. Except for being wild-caught and including both sexes, they were otherwise processed and given to the birds in a manner identical to the heliconiines. The Silverbeak Tanagers, Ramphocelus carbo magnirostris Lafresnaye, which served as indi- vidually caged predators, were obtained by net- ting with Japanese mist nets at Cumuto Village, Waller Field and the Arima Valley. Mature individuals of both sexes, and birds born in the spring preceding the summers’ experiments, were used. According to Herklots (1961), the Silverbeak breeds from February to August with the peak in April. Some of the birds were there- fore quite young. They are a common species in Trinidad, and were suggested for experimental use by Dr. David Snow of Oxford University who informed us that they are omnivorous. We have observed them eating berries and in the early morning they were also seen on the Station grounds pecking up insects that had been at- tracted by laboratory lights the previous night. On June 21, 1963, a male Silverbeak was seen by Jogie Ramlal to capture a red and black Heliconius ( H . erato or H. melpomene) on the wing in the natural habitat at Waller Field. Several birds at a time (up to 10) were used in an experiment, and a surplus was maintained in a storage cage for replacements after it was found that mortality among them was high. Towards the end of the second summer it was found that deaths could be reduced by putting freshly-captured individuals in a flight cage with others which had become cage-adapted. The experimental bird cages were modified from our basic design used previously at the Archbold Biological Station, Florida (J. Brower, 1958a). Each was a 30-inch cube framed with galvanized steel and covered with 14 -inch gal- vanized wire mesh. The front was covered by a removable galvanized steel sheet into which was set at eye level a piece of one-way glass 8 inches by 8 inches. A small sliding door was present at the bottom center of the front. A 60-watt incandescent light was placed over the center of each cage. In this way the light was such that the inside could be seen by an observer looking in through the glass, but a bird occupying the cage could not see out. This helped to shorten the time taken for a bird to adapt and lessened distractions in the environment during an ex- periment. Each cage was equipped with a sand- covered floor, a water tube and a basic diet of commercial dog food, corn meal and banana mashed together plus one-half of a banana sliced longitudinally. This food was removed from the birds’ cages at 6:50 a.m., the experi- ments were conducted from 8:00—11:30 a.m. and the food was replaced thereafter. The ten cages were in a roofed, large, outdoor cage covered with screening to prevent individuals from accidentally escaping during transfer. The sand was cleaned approximately once a week by sifting. The butterflies were presented to the birds with 12-inch-long forceps. The sliding door was opened, the butterfly placed on the center of the sand floor, dorsal side up with wings outspread, the forceps were removed, and the door was shut. Each bird was allowed two minutes, timed with a stopwatch (or sweep-second wristwatch) to respond to each butterfly. The birds charac- teristically ate the Euptychia edibles by pecking them up and swallowing them whole. Butterflies not touched or dismembered were removed from the cage immediately after the two-minute period. Each bird was given at least 12 hours to become familiar with its own cage and was required to eat five or more Euptychia edibles in a one morning period before qualifying for the experiment. A large number of birds failed this initial test, even though worked with for several consecutive mornings. IV. Experimental Design Experimental procedure was as follows (see also Table 1 and Plate I). Individuals of one of eight species of heliconiines, consisting of four pairs with both members in each similar in size, shape and color-pattern, were offered one at a time to the singly-caged bird predators. Twenty males of one heliconiine species were given to a bird along with twenty satyrid edibles. The sequence of presentation of these models and edibles was determined randomly by pairs, as in earlier experiments (J. Brower, 1958a). In this way, no bird could learn on the basis of the order of presentation whether the next butterfly would be an edible or a model. Three to five trials (six to ten butterflies in total) were offered to a bird per day. As soon as a bird had been given the 20 models, the presumed Mullerian mimic was substituted for the model for five trials to 1963] Brower, Brower & Collins: Experimental Studies of Mimicry 69 test for mimicry. Initially it was thought that considerable variation in the treatment of the mimics would occur and for this reason five mimics were given to allow for variance anaylsis. However, the results were so consistent that the treatment of only the first of the five mimics is analyzed in this paper (see Table 5). Finally a single other heliconiine butterfly, which will be called the “generalization butterfly,” was offered to the bird. This differed in color and pattern from the model-mimic pair (Plate I) and was given to clarify the basis of rejection of the mimic heliconiine, that is, whether the bird would confuse only two very similar heli- coniines, or whether it would generalize and reject any heliconiine butterfly regardless of its degree of resemblance to the model. It was planned to run a series of 10 birds simultaneously with several different species of heliconiines. All birds in any one series were to receive the same random sequence. At the completion of one series of birds, a second would be initiated, with all receiving a second random Table 1. Experimental Procedure Example of one random sequence of presentation of a heliconiine model, its respective Mullerian mi- mic, standard edible insects ( Euptychia spp.), and the generalization heliconiine offered one at a time to individually caged Silverbeak Tanagers. la Edible b Model 2a Edible b Model 3a Model b Edible 4a Edible b • e Model Palatability Test © • 20a Model b Edible 21a Mimic b • Edible • • Mimicry Test* 25a Mimic b Edible 26a Generalization Heliconiine Generalization Test b Edible *Five mimics were given but analysis is based solely on the first one (see text). sequence. However, it was impossible to keep the birds in phase because some would eat more butterflies per day than others, some began to reject all edibles part way through the experi- ment and. had to be eliminated, while others died before completing the run. Thus in practice several different random sequences were run simultaneously and out of phase. It was also planned to repeat the series several times so that results from a total of 10 birds for each of the 8 heliconiine species and its corresponding mimic could be compared. Table 2 shows the actual number of birds and butterflies tested, which is somewhat less than hoped for but nevertheless substantial. (It was not possible to investigate the palatability of H. Isabella ). At the completion of the experiment the pal- atability of the butterflies was compared by statistically testing (F and t tests) the numbers of heliconiines not touched by the birds out of the 20 each was given, or less than 20 in the 9 instances where birds died or stopped eating edibles (Tables 3 and 4). With one exception (Table 3, superscript 6), birds which failed to complete less than 10 trials were disqualified so as to avoid biasing the data towards accepta- bility. Mullerian mimicry was tested by a two-step chi square analysis, using the birds as their own controls. First, if generalized rejection of all heliconiine-like butterflies occurs after the birds learn not to touch the models through the series of trials, the number of birds which reject the mimic should be greater than the number of the same birds which previously rejected their first model (Tables 5, 6a). Second, if detailed Mullerian mimicry is operative, the number of birds which reject the mimic should be higher than the number of the same birds which reject the generalization butterfly (Tables 5, 6b). V. Results and Discussion (A). General Unpalatability of Heliconiine Butterflies The data in Table 2 confirm the prediction made at the outset of the experiment that heli- coniine butterflies are generally unpalatable in- sects to avian predators. Whereas the Silverbeaks ate all the satyrid butterflies, they accepted only three heliconiine species as food and these only to a slight extent, the maximum number eaten being one-fourth of both Dry as iulia and Agrau- lis vanillae. The only other species they ate were Heliconius doris and H. melpomene, and these only 11% and 1% of the time, respectively. Moreover, an examination of the peck and kill categories, added together in Table 2, shows that the birds as a group were remarkably uniform 70 Zoologica: New York Zoological Society [48: 7 Table 2. Mean Reactions of 62 Singly Caged Silverbeak Tanagers to 1,177 Individuals of 7 Species of Neotropical Heliconiine Butterflies as Models. Butterfly Species Relative Frequencies of Reactions Numbers of Not Touch Peck Kill Eat Butterflies Birds Heliconius numata .91 .08 .01 .00 136 7 Heliconius melpomene .90 .08 .01 .01 167 9 Heliconius erato .82 .12 .06 .00 175 10 Heliconius sara .82 .10 .08 .00 160 8 Heliconius doris .71 .11 .07 .11 180 9 Dryas iulia .62 .07 .06 .25 201 H Agraulis vanillae .58 .08 .10 .25 158 8 Totals 1,177 62 in their behavior towards the butterflies. Either they learned not to take them in a few trials, ranging from 9% of the total trials for H. numata and H. melpomene to 13% for D. iulia, and to 1 8 % for H. erato, H. sara, H. doris and A. vanillae, or they found them palatable and ate them. In other words, if the birds found the insects unpalatable, they rapidly associated this with their appearance and learned to reject them on sight after an average of between approxi- mately 1.8 and 3.6 trials. (B) Specific Differences in Palatability In Table 3 the heliconiine species are ar- ranged in order of increasing acceptability from left to right, as shown by the individual and mean relative frequencies of butterflies not touched by the birds. The differences are ana- lyzed statistically in Table 4 and the logic of the analyses will now be presented. Dixon & Massey (1957) was consulted for statistical procedures, and the .05 level of formal significance was chosen. Examination of the data for individual birds as well as the variances for each group of birds shows that their treatment of the last three species was considerably more variable than that of the first four, which they more consistently rejected. Bartlett’s test for the homogeneity of the seven variances shows lack thereof (P < .001, Table 4a), indicating that the difference in variability of the birds’ behavior towards H. numata, H. melpomene, H. erato and H. sara as one group and H. doris, D. iulia and A. van- illae as a second group is real. This grouping is legitimate for two reasons. First, the variances within each group are homogeneous (.50 > P >.25 for both, Table 4a). Secondly, while the Table 3. Ranked Relative Frequencies, Means, and Variances of Heliconiine Butterflies Not Touched as Models by 62 Singly Caged Silverbeak Tanagers* For statistical analyses, see Table 4. Heliconius Heliconius Heliconius Heliconius Heliconius Dryas Agraulis numata melpomene erato sara doris iulia vanillae .95 .95 1.006 .95 .95 .95 .90 .95 .95 .85 .90 .90 .95 .8318 .95 .95 .85 .90 .85 .95 .80 .9416 .90 .85 .85 .85 .90 .80 .90 .90 .85 .80 .85 .80 .75 .85 .8817 .801° .75 .85 .75 .25 .85 .85 .8019 .75 .55 .7311 .20 .85 .80 .65 .50 .6010 .10 .8010 .79 .10 .15 .75 .10 .00 Means** .91 .90 .82 .82 .71 .62 .58 Variances .003 .004 .004 .010 .078 .135 .110 No. Birds 7 9 10 8 9 11 8 *Superscript figures represent total heliconiine models given to the bird when not 20, due to bird’s death or failure to continue eating edibles. **Means are calculated from No. Not Touched 4- No. Given for all birds as in Table 2, which explains discrepancy of .01 for H. melpomene, H. erato and D. iulia if means are calculated from individual frequency values in this table. 1963] Brower, Brower & Collins: Experimental Studies of Mimicry 71 larger variance of H. sara compared to the others in its group might suggest that it belongs to the second group, Bartlett’s test shows that it is illegitimate to include it therein (P < .025, Table 4a). Thus on the basis of variability of treatment, the three species of butterflies in the second group appear to be more palatable than the four in the first. The F-test applied to the first four species indicates that the differences of the means do not quite reach significance at the .05 level (Table 4b). The reason for this can be seen by examining the data and comparing the means of the four species by pairs with the t-test. These four themselves break into two subgroups. H. erato and H. sara were both rejected with a mean frequency of .82, while H. numata and H. melpomene were rejected with a mean fre- quency of .91 and .90, respectively. Compari- sons between members of these two groups are all statistically significant, P varying from less than .005 to less than .05 (Table 4c). From this it can be concluded that H. numata and H mel- pomene are nearly alike in palatability, but less acceptable than the similar H. erato and H. sara. The F-test for the last three species indicates that the means do not differ significantly from each other (.50 > P > .25, Table 4b). This is due to the large variances in the treatment of these three species by the birds. The indicated trend of increasing palatability from H. doris to A. vanillae will almost certainly prove to be significant when more data are available. Table 4. Statistical Analyses of Data in Table 3 a. Bartlett’s test for homogeneity of variances. 1. All seven species: F = 8.900 d.f. = 6/3200 PC.001 2. H. numata, H. melpomene, H. erato, and H. sara: F = .633 d.f. = 3/1667 .50>P>.25 3. H. doris, D. iulia, and A. vanillae: F = .336 d.f. = 2/1333 ,50>P>.25 4. H. sara, H. doris, D. iulia, and A. vanillae: F = 3.276 d.f. = 3/1667 .025>P>.01 b. Variance analyses of groups of means (F-test). 1. H. numata, H. melpomene, H. erato, and H. sara: F = 2.66 d.f. = 3/30 .10>P>.05 2. H. doris, D. iulia, and A. vanillae: F = .318 d.f. = 2/25 ,50>P>.25 c. Variance analyses of means by pairs within groups having homogeneous variances (t-test). t d.f. P H. numata vs. H. melpomene (not significant by inspection) H. erato vs. H. sara (not significant by inspection) H. numata vs. H. erato 3.00 15 P<.005 H. numata vs. H. sara 2.14 13 .05>P>.025 H. melpomene vs. H. erato 2.76 17 PC.01 H. melpomene vs. H. sara 2.00 15 .05>P>.025 H. doris vs. A. vanillae .88 15 ,90>P>.80 Variance analyses of means by pairs betweer i groups not having homogeneous variances (modified t-test, see text). t d.f. P H. numata vs. H. doris 2.06 9 .05 >P>.025 H. numata vs. D. iulia 2.59 11 .025>P>.01 H. numata vs. A. vanillae 2.77 7 .025>P>.01 H. melpomene vs. H. doris 2.00 9 .05 >P>.025 H. melpomene vs. D. iulia 2.37 11 .025>P>.01 H. melpomene vs. A. vanillae 2.69 7 .025>P>.01 H. erato vs. H. doris 1.15 9 .20 >P>.10 H. erato vs. D. iulia 1.79 11 .10 >P>.05 H. erato vs. A. vanillae 2.02 7 .05 >P>.025 H. sara vs. H. doris .9 10 .20 >P>.10 H. sara vs. D. iulia 1.75 13 .10 >P>.05 H. sara vs. A. vanillae 1.95 8 .05 >P>.025 72 Zoologica: New York Zoological Society [48: 7 Since the variances of the first four and last three differ so greatly, it is necessary to employ a modified t-test (Bennett & Franklin, 1954) to compare mean treatments by pairs between the two groups. When this is done, it is seen that with the exception of H. erato and H. sara, which do not differ significantly from H. doris or D. iulia, all other paired comparisons are significant below the .05 level (Table 4d). From this analysis, the general conclusion is that the heliconiines do differ in their paya- bility. On the basis of the more variable treat- ment and the lower mean numbers rejected of the last three species, this group as a whole is more palatable than the group including H. numata, H. melpomene, H. erato and H. sara. Within these four, it is clear that H. melpomene and H. numata are less palatable than H. erato and H. sara. (C) . Phylogenetic Relationships and Palatability It has long been known that the Lepidoptera represent a unique biological system for the measurement of evolutionary forces in nature. Bates (1863, P. 353) pointed this out graphically when he said nature writes on their wings “as on a tablet the story of the modifications of species, so truly do all changes of organization register themselves thereon.” Goldschmidt (1945) presented a review of the ontogenetic development of pigment patterns in the Lepidop- tera which summarized the facts and. clarified the physiological basis of Bates’ speculations. Briefly, the sequence of events that results in the development of pattern and color in the wings of these holometabolous insects does not begin until very late in the pupa, when the in- dividual has nearly completed its transformation to the adult stage. If a mutation occurs which affects a process in the early part of this se- quence, the resultant phenotype will be strik- ingly different, and conversely if it occurs later, the change in appearance will be correspond- ingly less. The most important functional con- sequence of this ontogenetic system is that both small and large changes in color-pattern can occur whose effect on other physiological proc- esses of the individual is but slight. In other words, centripetal selection (Haldane, 1959) against genes which affect the color-pattern is weak because their adverse pleiotropic effects on the physiology of the individual are small, or in Wright’s (1932) terminology, the valleys between adaptive peaks are shallow (Dobzhan- sky, 1951). The result of this is seen in the vast evolutionary diversification of color-pattern in the Lepidoptera and even more dramatically by the changes that can occur very rapidly in natural populations as actually observed in the instances of breakdown of mimetic pattern in the African nymphaline butterfly, Pseudacraea eurytus (Linnaeus) (Carpenter, 1920, 1949; Sheppard, 1959) ; and the modifications in color form of another nymphaline, Melitaea aurinia Rott. (Ford & Ford, 1930). Generally speaking, as Bates (1863) also emphasized, the color patterns of the wings are indicative of phylogenetic relationships in the Lepidoptera. But one of the outstanding facts of mimicry is that this principle is violated be- cause selection has favored the similarity of ap- pearance between forms whether they are re- lated, as is often the case in Mullerian mimicry, or not related as is always true in Batesian mim- icry. In Mullerian situations, it is important to consider the difficulty alluded to by Fisher (1958, p. 173), of deciding whether the re- semblance of two unpalatable species which are congeneric is the result of ( 1 ) convergent evolu- tion in appearance due to Mullerian advantage, (2) parallel evolution, or lack of divergence, in appearance due to Mullerian advantage, or (3) parallel evolution, or lack of divergence, in ap- pearance without Mullerian advantage being involved. Darlington (1938, P. 686) struggled with this problem in lycid Beetles when he said, “The great similarity of the three Cuban species of Thonalmus may possibly be an example of Mullerian mimicry, but on the other hand, it may be due merely to their close relationship.” As such, he considered only the first and third alternatives. The second possibility apparently did not occur to him, namely, that the beetles may have derived a Mullerian advantage with the result that any mutations causing a diver- gence in their appearance were prevented from becoming established. The point to be empha- sized is that close affinity does not preclude Mullerian relationships since the selective proc- ess in preventing divergence can be basically the same as that bringing about convergence of widely different unpalatable organisms. Fox (1956, p. 10) also failed to appreciate the three possible alternatives in his revision of the Itho- miidae. He noted that pairs of distantly related species which are congeneric, or even those in different genera, occasionally are so similar that it is impossible to tell them apart by superficial examination, and said, “These are cases of par- allel evolution, and whether ‘mimicry’ causes them or not I cannot say, but I am doubtful that it does.” Once Mullerian advantage is dem- onstrated experimentally in any given instance, the third possibility becomes less probable. The choice between the first and second alternatives then rests on the determination of the phylo- 1963] Brower, Brower & Collins: Experimental Studies of Mimicry 73 genetic relationships by taxonomic characters more conservative than color-pattern, i.e., those characters on which the forces of centripetal selection resist change to a greater degree. Classi- cally, these are the external morphological char- acters of eggs, larvae, pupae and adults, and the characters of the adult genitalia, but they should also include behavioral patterns, as pointed out by Crane and her co-worker for the Heliconiinae (Crane, 1957; Alexander, 1961a, b) as well as in the reviews of Hinde & Tinbergen (1958) and Mayr (1958) for animals in general. The study of differences in palatability among re- lated species should also provide valuable evi- dence for their phylogenetic relationships. Al- though not emphasized previously, this is to be expected because the evolution of unpalata- bility may be autotoxic, which requires major biochemical readjustments (Roth & Eisner, 1962) that are bound to proceed at a rate slower than change in color. Phylogenetic conclusions based on comparative studies of morphology, behavior and palatability may therefore be ex- pected to produce a considerable degree of con- cordance. As shown by the present experimental study, the Heliconiinae, long assumed to be unpala- table to birds, are in fact so. These butterflies are a specialized subfamily of the large and diverse family Nymphalidae (Michener, 1942). On the basis of a large number of feeding exper- iments (Carpenter, 1921; Jones, 1932; Marshall, 1902, Pocock, 1911; Swynnerton, 1919) and extensively developed cryptic coloration (Cott, 1957) , it is clear that the more primitive Nymphalidae (the subfamily Nymphalinae) are generally tasteful insects to avian predators, al- though their palatability characteristics should be considered relative rather than absolute, as discussed in theory by Fisher (1927, 1930, 1958) , Nicholson (1927) and Carpenter & Ford (1933), and demonstrated by J. Brower (1958a, b, c) . From these considerations it was predicted at the outset of the experiment that the heli- coniine species phylogenetically closest to the Nymphalinae would be the most palatable. De- tailed morphological studies of the immature stages of the Trinidad species by Fleming (1960) and Beebe, Crane & Fleming (1960) indicated that Agraulis vanillae and Dryas iulia, and also probably Heliconius doris, are closest to the nymphaline stock of the seven species tested in the present study. The more limited conclusions of Alexander (1961a, b), based on the comparative behavior of the immature stages, also agreed with this. It is therefore of the greatest interest that these three species were in fact found to be the most palatable (Tables 2, 3 and 4, and see above) . Crane and her co-workers have also given evidence that H. numata, H. melpomene and H. erato form a close group within which the former two species are more closely related than either is to H. erato, in spite of the fact that H. melpomene and H. erato are nearly indistin- guishable as adults. The palatability data statis- tically confirm this since the birds treated H. numata and H. melpomene in a similar manner whereas their treatment of both of these differs significantly from H. erato (P < .005, P < .01, respectively, Table 4c). The birds’ treatment of H. erato and H. sara is also consistent with their scheme. Thus the palatability characteristics of the adult male heliconiines in this study are re- markably concordant with the phylogenetic con- clusions based on morphology and behavior. Now that the relationships of H. numata, H. melpomene and H. erato have been partially elucidated, it would be of the greatest interest to initiate a program of hybridization in an at- tempt to reconstruct further the evolutionary changes that led, for example, to the converg- ence in color and pattern of H. melpomene and H. erato, or as another alternative, to the diver- gence of H. numata from the melpomene-erato color-pattern through its convergence with the H. Isabella color-pattern. (D). Mullerian Mimicry It may be seen in Table 5 that 21 out of 62 (34% ) of the birds did not touch the first model given, although all but one subsequently pecked, killed or ate at least one model in their individual series of 20. Taking these initial rejections of models as a base line for comparison, we should expect that the birds would not touch a higher proportion of mimics after experiencing the series of 20 models if mimicry is effective. Of the 62 birds which began the experiment, 10 died and 8 either found the heliconiines palatable or failed to learn to avoid them on sight, leaving a total of 44 birds. Of these, 42 (95%) did not touch their first mimics (Table 5). In other words, 61% more of the birds rejected their mimics than their first models. This difference is highly significant (P < .001, Table 6a). It can be seen in Plate I that the difference in appearance between the satyrid edibles and the heliconiine models and mimics is greater in size, shape, contrast and brightness of color than among the heliconiines themselves. The possi- bility therefore existed in the experiment that the birds, having discovered the difference in palatability between the two, would form a gen- eralized rejection response towards all helico- niine-like butterflies. If this were true, it would be expected that the birds which learned to reject 74 Zoologica: New York Zoological Society [48: 7 Table 5. Comparison of the Number and Frequency of Birds which Rejected Their First Models Compared to the Same Birds which Subsequently Rejected Their First Mimics and Generalization Butterflies After Having Experienced 20 Models For statistical analyses, see Tables 6-9. Generalization Butterflies Numbers and Frequencies of Birds Not Touching Models Mimics First Model First Mimic Generalization Butterfly H. numata H. melpomene H. erato H. sara H. doris D. iulia A. vanillae II. isabella H. erato H. melpomene H. doris H. sara A. vanillae D. iulia ) doris \ vanillae vanillae vanillae vanillae vanillae doris doris 4/7 (.57) 4/9 (.44) 5/10 (.50) 0/8 (.00) 3/9 (.33) 3/11 (.27) 2/8 (.25) 5/6 (.83) 7/7 (1.00) 6/6 (1.00) 7/8 (.88) 7/7 (1.00) 6/6 (1.00) 4/4 (1.00) ) 1/2 (.50) )2/4 (.50) 3/7 (.43) 2/5 (.40) 6/8 (.75) 1/7 (.14) 6/6 (1.00) 4/4 (1.00) Totals 21/62* (.34) 42/44* (.95) 25/43** (.58) ♦Discrepancy of 18 birds due to the death of 10, plus 8 which did not learn to reject models before being given mimics. ♦♦Discrepancy of 1 bird due to death prior to being given the generalization butterfly. the models would reject their mimics and gen- eralization heliconiines to approximately the same extent. This they did not do; 95% of them in fact rejected the mimics as compared to 58% for the generalization insects (Table 5). This difference of 37% greater protection for the mimics is highly significant (P < .001, Table 6b). Since it has been shown that all seven of the heliconiine butterflies studied were distaste- ful, it is concluded that detailed Mullerian mim- icry is highly effective under the conditions of the experiment. Moreover, an examination of the data for individual birds in Table 5 shows that they were extremely consistent in reducing their attacks on the mimics; in no model-mimic pair was the percent not touching the mimics less than that not touching first models. Reasons why a considerable proportion of the birds re- jected their first models and generalization heli- coniines will be considered below. (E). Evidence that Mullerian Mimicry Operates in Nature 1. Treatment of First Models All the birds used in these experiments were captured in the wild and used in the tests within one week after being caught. In so far as the heliconiine butterflies studied are among the most abundant diurnal Lepidoptera in Trinidad, it seems likely that the birds may have had prior experience with them in nature. It has been shown above that all the birds, with a single exception, attacked at least one of the helico- niines given to them in the series of 20. How- ever, one-third of the birds (21/62) rejected the initial model (Table 5). On the hypothesis that these rejections were based partly on the birds’ remembrance of a prior experience in the wild with the unpalatable butterflies, it is to be expected that the heliconiines most rejected ini- tially would be those which are the commonest in the habitats where the buds occur, since it would be these with which the birds would most likely have come in contact. Now in the lower montane and savanna forest where the Silver- beak Tanagers breed and are abundant, without doubt the most common distasteful butterfly seen is Heliconius erato. Moreover, although H. numata itself is not generally abundant, there exists a whole assemblage of classical Mullerian mimics similar to it in color and pattern which fly together. These include not only H. numata and H. Isabella, but at least seven species belong- ing to the Ithomiidae and also Lycorea ceres ceres (Cramer), a member of the Danaidae. Assuming that these other species are in fact un- palatable, as the heliconiines are, we can then say that the birds should, when brought into the laboratory and tested, reject a higher proportion of H. numata, H. Isabella, H. erato and the lat- ter’s very close Mullerian mimic, H. melpomene, than the other four species. The data in Table 7a, extracted from Table 5, fully confirm this ex- pectation (except for H. isabella, for which palatability tests were not made). Thus 50% of the birds as a group did not touch the initial models when these were H. numata, H. melpo- mene and H. erato, whereas only 22% of them rejected the initial individuals of H. sara, H. doris, D. iulia and A. vanillae. This difference is statistically significant (P < .05). 1963] Brower, Brower & Collins: Experimental Studies of Mimicry IS Table 6a. Statistical Analysis of the Reactions of All Birds to Their First Model vs. the Same Birds’ Reactions to Their First Mimic, Showing that Mullerian Mimicry is Highly Effective Either Through Detailed Mimicry or Through Generalized Rejection of All Heliconiine-like Butterflies. (Data from Table 5). Category of Reaction Reaction of Birds to First Model First Mimic Totals Not Touch Peck, Kill, or Eat 21 (34%) 41 42 (95%) 2 63 43 Totals 62 44 106 Exact chi square = 37.74; d.f. = 1; P < .001 Table 6b. Statistical Analysis of the Reactions of All Birds to Their First Mimic vs. the Same Birds’ Reactions to Their Generalization Butterfly, Showing that Detailed Mimicry Confers Protection Beyond that Resulting from Generalization. (Data from Table 5). Reaction of Birds to Category of Reaction Generalization First Mimic Butterfly Totals Not Touch 42 (95%) 25 (58%) 67 Peck, Kill, or Eat 2 18 20 Totals 44 43 87 Exact chi square = 15.06; d.f. = 1; P < .001 An alternative explanation for the greater ini- tial rejection of H. numata, H. melpomene and H. erato is that the birds had tried all seven spe- cies in nature, but had remembered their experi- ence to a greater extent for these three species because of their demonstrated high unpalata- bility. This explanation seems the less likely be- cause, if it were correct, then H . sara should have been rejected initially to an extent as great as H. erato whose palatability characteristics it shares (Tables 3 and 4), and it clearly was not (Table 5). Moreover, if palatability were the basis, there should be some tendency for the birds to reject H. sara and H. doris initially to a greater extent than D. iulia and A. vanillae. This is definitely not so, as shown statistically in Table 7b. However, no matter which of these explanations is correct, both are based on prior experience. Therefore, the hypothesis is support- ed that these birds actually were involved as selective agents for the evolution of Mullerian mimicry in Trinidad when they were captured. Two other potential explanations exist which are not based on prior experience. It might be argued that the rejection of more of these first three species could be the result of a size differ- ential between them and the last four. This, how- ever, is excluded because the size range of the former group is included completely within that of the latter (see Plate I). Secondly, the birds might have an innate tendency to reject them. This is unlikely for several reasons. First of all, one of the characteristics of innate behavior is its consistency, and if operating here we should expect the birds to behave uniformly towards the model species, either all rejecting or all accept- ing them. Considering the treatment of first models again, we see that only in the instance of H. sara were the birds uniform (Table 5), and on the average 34% attacked them, which is clearly neither consistent rejection nor accept- ance. Furthermore, all the birds except one at- tacked at least one model in the series of 20. Finally, as will be discussed in a future publica- tion, innate compared to learned rejection re- sponses towards potential food items bearing the kinds of patterns that are involved in mim- icry are highly inefficient from an ecological viewpoint in animals that have a reasonable capacity to learn. Briefly, this is because in Ba- tesian mimicry the predators would be deprived of a valuable food supply should the mimic species come greatly to outnumber the model. 76 Zoologica: New York Zoological Society [48: 7 Table 7a. Statistical Analysis of the Reactions of Birds to Their First Model, Comparing H. numata, H. melpomene and H. erato vs. H. sara, H. doris, D. iulia and A. vanillae. See Text for Interpretation. (Data from Table 5). Category of Reaction Reaction of Birds to First Model of the Species n., m.t e. s., d., i., v. Totals Not Touch Peck, Kill, or Eat 13 (50%) 13 8 (22% ) 28 21 41 Totals 26 36 62 Exact chi square = 4.03; d.f. = 1; .05 > P > .025 Table 7b. Statistical Analysis of the Reactions of Birds to Their First Model, Comparing H. sara and H. doris vs. D. iulia and A. vanillae. See Text for Interpretation. (Data from Table 5). Category of Reaction Reaction of Birds to First Model of the Species s., d. L, V. Totals Not Touch 3 (18%) 5 (26%) 8 Peck, Kill, or Eat 14 14 28 Totals 17 19 36 Exact chi square = .05; d.f. = 1; P > .20 This is bound to occur occasionally as animals typically fluctuate in abundance (Lack, 1954). Moreover, because palatability is a relative phe- nomenon, as discussed above, depending among other things on the degree of the predator’s hun- ger, to be predisposed never to take warningly- colored insects and those involved in Mullerian mimicry seems similarly inefficient. Thus on the basis of the data presented in this paper and from more general considerations, the hypothesis of innate rejection of these heliconiine butterflies is discarded (see also Brower & Brower, 1962a, where similar findings were obtained with toads as experimental predators of bees and mimetic flies) . 2. Treatment of Generalization Butterflies The birds’ responses to the generalization but- terflies, H. doris and A. vanillae, compared to their treatment of the first models, as well as a comparison between the two generalization spe- cies, provide an additional line of evidence that they had had prior experience with these heli- coniines in nature. In Table 8a, it can be seen that the birds as a group rejected the generalization butterflies to a greater extent (58%) than the first models (34%). This difference of 24% is statistically significant (P < .025). Tables 8b and 8c break down Table 8a and show that the significance is due to the birds’ rejection of H. doris (Table 8b) as the generalization butterfly, but not A. vanillae (Table 8c), and Table 8d shows that the differ- ence between H. doris and A. vanillae is indeed significant (P < .025). In other words, after the birds received their series of distasteful H. numata, H. melpomene, H. erato, H. sara and H. doris, they did not reject A. vanillae as the generalization insect (Table 8c) ; but after their series of distasteful A . vanillae and D. iulia, they did reject H. doris as the generalization insect (Table 8b). The most probable explanation of the treatment of A. vanillae as the generalization insect is that the birds did not associate it with the bicolored Heliconius spp. The fact that the birds’ rejections of A. vanillae and D. iulia as first models did not differ significantly from their rejections of A. vanillae when it was the general- ization insect (P > .20, Table 9a) further sup- ports this view. On the other hand, it seems most probable that the birds’ rejection of H. doris as the generalization insect after their series of A. vanillae or D. iulia is based on the fact that dis- tasteful monocolored heliconiines in some way recalled prior experience with H. doris, or H. sara, or with the bicolored Heliconius spp. in general which they had learned in nature were even more distasteful than D. iulia or A . vanillae. The fact that the birds’ rejections of H. doris (and H. sara) as first models did differ signifi- cantly from their rejection of H. doris as the generalization insect (P < .001, Table 9b) sup- ports this view. 1963] Brower, Brower & Collins: Experimental Studies of Mimicry 77 Table 8a. Statistical Anaylsis of Reactions of All Birds to Their First Model vs. the Same Birds’ Reactions to Their Generalization Butterfly, Showing that the Birds Do Generalize. (Data from Table 5). Reaction of Birds to Category of Reaction First Model Generalization Butterfly Totals Not Touch Peck, Kill, or Eat 21 (34%) 41 25 (58%) 18 46 59 Totals 62 43 105 Exact chi square = 5.13; d.f. = 1; .025 > P > .01 Table 8b. Statistical Anaylsis of Reactions of Birds to Their First Model vs. The Same Birds' Reactions to Their Generalization Butterfly When Models Are D. iulia and A. vanillae and the Generalization Butterfly is H. doris, Showing that Birds Do Generalize to H. doris. (Data from Table 5). Reaction of Birds to Category of Reaction First Model (/. & V.) Generalization Butterfly (d.) Totals Not Touch Peck, Kill, or Eat 5 (26%) 14 10 (100%) 0 15 14 Totals 19 10 29 Exact chi square = 11.45; d.f. = 1; P < .001 Table 8c. Statistical Analysis of Reactions of Birds to Their First Model vs. the Same Birds’ Reactions to Their Generalization Butterfly When Models Are H. numata, H. melpomene, H. erato, H. sara and H. doris and the Generalization Butterfly is Agraulis vanillae, Showing that Birds Do Not Generalize to A. vanillae. (Data from Table 5). Reaction of Birds to Category of Reaction First Model (n., m., e., s., & d.) Generalization Butterfly (v.) Totals Not Touch 16 (37%) 14 (45%) 30 Peck, Kill, or Eat 27 17 44 Totals 43 31 74 Exact chi square = .20; d.f. = 1; P > .20 Table 8d. Statistical Analysis of Reactions of Birds to Their Generalization Butterfly, Show- ing Greater Generalization to H. doris than to A. vanillae. (Data from Table 5). Reaction of Birds to Category of Reaction Generalization Butterfly T ofals (v.) id.) Not Touch 14 (45%) 11 (92%) 25 Peck, Kill, or Eat 17 1 18 Totals 31 12 43 Exact chi square = 5.90; d.f. = 1; .025 > P > .01 78 Zoologica: New York Zoological Society [48: 7 Table 9a. Statistical Analysis of Reaction of Birds to A. vanillae and D. iulia as First Models*, Compared to the Reactions of Birds to A. vanillae as Their Generalization Butterfly After Experiencing H. numata, H. melpomene, H. erato, H. sara or H. doris As Models. See Text for Interpretation. (Data from Table 5). Reaction of Birds to Category of Reaction First Model (v. & i.) Generalization Butterfly (v.) Totals Not Touch Peck, Kill, or Eat 5 (26% ) 14 14 (45%) 17 19 31 Totals 19 31 50 Exact chi square = 1.07; d.f. — 1; P > .20 * Since the birds treated A. vanillae and D. iulia as Mullerian mimics, as well as H. doris and H. sara, it is legitimate to lump each pair as first models and consider the first as the “ vanillae visual species” and the second as the “doris visual species.” Table 9b. Statistical Analysis of Reactions of Birds to H. doris and H. sara as First Models*, Compared to the Reactions of Birds to H. doris as Their Generalization Butterfly After Experiencing A. vanillae and D. iulia as Models. See Text for Interpretation. (Data from Table 5). Reaction of Birds to Category of Reaction First Model ( d . & s.) Generalization Butterfly (d.) Totals Not Touch Peck, Kill, or Eat 3 (18%) 14 10 (100%) 0 13 14 17 10 27 Exact chi square = 13.96; d.f. = 1; P < .001 *Since the birds treated A. vanillae and D. iulia as Mullerian mimics, as well as FI. doris and H. sara, it is legitimate to lump each pair as first models and consider the first as the “ vanillae visual species” and the second as the “doris visual species.” (F). Evidence that a Generalized Resemblance Confers a Mimetic Advantage If the species of the genus Heliconius (i.e., excluding Agraulis and Dryas) are carefully ex- amined, it is clear to a human observer that they are similar in shape, body form and details of morphology such as wing venation, antennae and legs. Wallace (1871, p. 85) referred to this “uniformity of type with great diversity of colouring,” and suggested that a predator would tend to recognize them as a unit of unpalatability. This statement was important because it alluded to the idea that a resemblance other than detailed similarity in color-pattern might be sufficient for a predator to associate the unpalatability of any one species with the others. Some experimental evidence has indicated that bird predators do tend to generalize from an unpleasant experience. The work of Lloyd Mor- gan (1900) was the first to demonstrate this. He showed that young chicks which were fed qui- nine-treated meal on a striped glass slip associ- ated the striped condition with the unpleasant food, because later they would not eat untreated meal from the banded slip. These same birds then refused to peck a striped Cinnabar cater- pillar which they had never seen before. In an- other experiment he showed that chicks trained to reject Cinnabar larvae would not touch wasps which they had never experienced. Windecker’s (1939) results confirmed the Cinnabar larva- wasp generalization. Miihlmann’s (1934) study with artificial models and mimics (painted meal- worms) also showed generalization by the bird predators. In experiments with butterflies which were offered to caged Scrub Jays, Aphelocoma c. coerulescens (Linnaeus)4, J. Brower (1958c) found that jays which had experienced the model Danaus plexippus (Linnaeus) later refused it 4Scrub Jays were previously referred to as Cyanocitta c. coerulescens (Bose) (J. Brower, 1958a, b, c) after Amadon (1944). 1963] Brower, Brower & Collins: Experimental Studies of Mimicry 79 and its mimic Limenitis archippus archippus (Cramer) on sight. Moreover, these birds also rejected on sight a different geographic race of the same species, L. a. floridensis, (Strecker) which mimics the much darker Danaus gilippus berenice (Cramer), and then even the latter. In addition, Schmidt (1958) found that domestic chicks learned to reject artificial models and then artificial mimics which were painted so as to be considerably different from the models in color- pattern. These experimental studies of generalization suggest that birds in nature are likely to treat incipient mimics conservatively. However, as Swynnerton (1915) was the first to emphasize, vertebrate predators which have associated the coloration of an insect with its distastefulness nevertheless characteristically make errors and attack the species again. Where incipient Muller- ian mimicry is involved, the predator’s mistake results in another unpleasant experience and so tends to lessen further attacks on both model and mimic at least temporarily. But even more im- portant was Swynnerton’s (1915) discovery that once a given warning pattern is learned, simply seeing the insects which bear the pattern, with- out attacking them, leads to a further reduction in the number of errors they make. The phe- nomenon in fact represents a general principle of animal behavior known as secondary rein- forcement (Thorpe, 1956). In his independent discovery of this, Swynnerton deduced an im- portant new principle of Mullerian mimicry, namely that the greater the numbers of un- palatable species and individuals which bear a common warning color-pattern, the fewer the mistaken attacks will be made. To take an ex- treme hypothetical example, if 100 attacks are made on 1,000 individuals, only 90 might be made on 2,000. It should be noted that the be- havioral principle (secondary reinforcement) in- volved here results in a type of mathematical death rate relationship which population biolo- gists recognize as “inversely density-dependent” (Holling, 1961), or in Nicholson’s (1954) termi- nology, “density-disturbing” (see also Varley, 1957). In view of this, one might wonder why all sympatric members of the Heliconiinae do not share a single color-pattern. The answer to this appears to lie in the balance between the protec- tive advantage of Mullerian mimicry, as opposed to mere warning coloration, and the courtship disadvantage that would result from interspecific interference among several sympatric species should they all bear the same visual cues (Poul- ton, 1907; L. Brower, 1959). Further work along these lines will possibly elucidate why certain of the heliconiines are polymorphic, which, as Shep- pard (1963) has pointed out, is contrary to pre- diction of Mullerian mimicry theory. On the other hand, it may well be that the large amount of convergence that has occurred in butterflies involved in Mullerian mimicry complexes (reaching its zenith in the “tiger-stripe” complex of the South American Ithomiidae, Heliconiinae and Lycoreinae; see Kaye, 1906, and Moulton, 1908) has been made possible by the greater importance of scent than sight stimuli in their courtship. Without exception, they all have ela- borate odor-disseminating organs, which is not true of those species which are Batesian mimics. This is discussed in detail elsewhere (L. Brower, 1963). It is well to remember that errors reinforce the lesson of distastefulness only if the situation is Mullerian; in Batesian mimicry the predator may be rewarded for his mistake by an edible insect, and if the frequency of a mimic becomes high enough, the predator will begin to take it regularly, and mimicry will tend to become of much less advantage, as demonstrated directly by experiment (J. Brower, 1960) as well as in- directly, as reviewed by Brower & Brower (1962b) and Sheppard (1959). Fisher, (1958, p. 166) has concisely described this aspect of Batesian and Mullerian mimicry as follows: “The Batesian mimic gains its advantage at the expense of the predator which it deceives, and of the model whose life it endangers. In the Mullerian system both species alike are mimic and model, each reaps an advantage of the same kind, and both cooperate to confer an advantage upon the predator by simplifying its education. The predator which requires to frustrate the wiles of a Batesian mimic should develop a keen and sceptical discrimination; while he will best take advantage of the Mullerian situation by general- ization, and reasoning from analogy.” This last phrase appears to fit the behavior of the Silver- beak predators used in this experiment. The line of reasoning developed in the last section (E-2) showed that a series of experiences with distaste- ful monocolored orange butterflies (A. vanillae and D. iulia) caused the birds to reject bicolored blue and yellow ones (H. doris). This finding, which suggests fascinating further research, is of the greatest importance to mimicry theory. It shows that a similarity in shape and size alone (compare H. doris to D. iulia and A. vanillae in Plate I) can result in a substantial selective advan- tage by provoking generalized rejection responses in birds which presumably have had considerable experience in the wild. As such, the data nullify experimentally for the first time with actual mimetic butterflies the argument of Punnet 80 Zoologica: New York Zoological Society [48:7 (1915) and Goldschmidt (1945), who main- tained that mimicry can not arise by the accumu- lation of small variations because the initial changes would not be at a selective advantage with regard to predators which had experienced the potential models. The contrary may now be stated as an experimentally demonstrated fact, namely, that even a remote resemblance between heliconiine butterflies can be advantageous. VI. Summary 1. Seven species of heliconiine butterflies (Heliconius numata, H. melpomene, H. erato, H. sara, H. doris, Dry as iulia and Agraulis vanil- lae) were shown to be unpalatable to 62 indi- vidually caged passerine bird predators, the Silverbeak Tanager. 2. Differences in unpalatability exist among the species, and in general correspond to the phylogenetic relationships of the butterflies. This supports the prediction of mimicry theory that palatability evolves more slowly than color and pattern. 3. Heliconius numata and H. melpomene are probably more closely related to each other than either is to H. erato, even though H. melpomene and H. erato are nearly indistinguishable as adults (see Plate I). 4. Under controlled procedure in experimental cages, four pairs of heliconiine butterflies which resemble each other (see Plate I) are highly effective Mullerian mimics. 5. Evidence is presented that the birds used in these experiments had experienced heli- coniines in nature and that Mullerian mimicry among these butterflies is conferring a protective advantage in Trinidad at the present time. 6. Data are presented which discard the hypo- thesis of innate rejection of warningly-colored heliconiines by the Silverbeak Tanager. 7. Evidence was found that even a generalized similarity in shape and size between two un- palatable species can result in a substantial selec- tive advantage, thus nullifying the hypothesis of Punnet (1915) and Goldschmidt (1945). VII. References Alexander, Anne J. 1961a. A study of the biology and behavior of the caterpillars, pupae and emerging butter- flies of the subfamily Heliconiinae in Trini- dad, West Indies. Part I. Some aspects of larval behavior. Zoologica, 46: 1-24. 1961b. A study of the biology and behavior of the caterpillars, pupae and emerging butter- flies of the subfamily Heliconiinae in Trini- dad, West Indies. Part II. Molting, and the behavior of pupae and emerging adults. Zoologica, 46: 105-123. Bates, H. W. 1862. Contributions to an insect fauna of the Amazon Valley, Lepidoptera: Heliconi- dae. Trans. Linnaean Soc. London, 23: 495-566. 1863. The naturalist on the River Amazons. Re- print of the unabridged edition, 1892. John Murray, London, 395 pp. Beebe, William, Jocelyn Crane, & Henry Fleming 1960. A comparison of eggs, larvae and pupae in fourteen species of heliconiine butter- flies from Trinidad, W.I. Zoologica, 45: 111-154. Belt, Thomas 1874. The naturalist in Nicaragua. E. P. Dutton, New York. 306 pp. Bennett, C. A., & N. L. Franklin 1954. Statistical analyses in chemistry and the chemical industry. John Wiley and Sons, New York. 724 pp. Brower, Jane Van Zandt 1958a. Experimental studies of mimicry in some North American butterflies. Part I. The Monarch, Danaus plexippus and Viceroy, Limenitis archippus archippus. Evolution, 12: 32-47. 1958b. Experimental studies of mimicry in some North American butterflies. Part II. Battus philenor and Papilio troilus, P. polyxenes and P. glaucus. Evolution, 12: 123-136. 1958c. Experimental studies of mimicry in some North American butterflies. Part III. Dan- aus gilippus berenice and Limenitis archip- pus floridensis. Evolution, 12: 273-285. 1960. Experimental studies of mimicry. IV. The reactions of Starlings to different propor- tions of models and mimics. American Naturalist, 94: 271-282. Brower, Jane Van Zandt, & L. P. Brower 1962a. Experimental studies of mimicry. 6. The reaction of Toads ( Bufo terrestris ) to Honeybees ( Apis mellifera) and their Dronefly mimics (.Eristalis vinetorum). American Naturalist, 96: 297-307. Brower, L. P. 1959. Speciation in butterflies of the Papilio glaucus group. II. Ecological relationships and interspecific sexual behavior. Evolu- tion, 13: 212-228. 1963. The evolution of sex-limited mimicry in butterflies. Proc. XVIth International Con- gress of Zoology, 4: 173-179. Brower, L. P., & Jane V. Z. Brower 1962b. The relative abundance of model and mimic butterflies in natural populations of the Battus philenor mimicry complex. Ecology, 43: 154-158. 1963] Brower, Brower & Collins: Experimental Studies of Mimicry 81 Brower, L. P., Jane Van Zandt Brower, & P. W. Westcott 1960. Experimental studies of mimicry. 5. The reactions of Toads (Bufo terrestris) to Bumblebees (Bombus americanorum) and their Robberfly mimics (Mallophora bom- boides), with a discussion of aggressive mimicry. American Naturalist, 94: 343- 355. Carpenter, G. D. H. 1920. Pseudacraea eurytus hobleyi, its forms and its models on the islands of L. Victoria and the bearing of the facts on the explana- tion of mimicry by natural selection. Trans. Entomological Soc. London, 1920: 84-98. 1921. Experiments on the relative edibility of insects, with special reference to their coloration. Trans. Entomological Soc. London, 1921: 1-105. 1949. Pseudacraea eurytus (L.) (Lep. Nympha- lidae): a study of a polymorphic mimic in various degrees of speciation. Trans. Royal Entomological Soc. London, 100: 71-133. Carpenter, G. D. H„ & E. B. Ford 1933. Mimicry. Methuen and Co., Ltd., London. 134 pp. Clarke, C. A., & P. M. Sheppard 1960. Super-genes and mimicry. Heredity, 14: 175-185. 1962. The genetics of Papilio dardanus Brown. IV. Data on race ochracea, race flavicornis and further information on races poly- trophus and dardanus. Genetics, 47 : 909- 920. Cott, H. B. 1957. Adaptive coloration in animals. Methuen and Co., Ltd., London. 508 pp. Crane, Jocelyn 1957. Imaginal behavior in butterflies of the family Heliconiidae: changing social pat- terns and irrelevant actions. Zoologica, 42 : 135-145. Darlington, P. J., Jr. 1938. Experiments on mimicry in Cuba, with suggestions for future study. Trans. Royal Entomological Soc. London, 87: 681-696. Dixey, F. A. 1897. Advances in Mullerian mimicry in South America. Proc. Entomological Soc. Lon- don, 1897: xx-xxxii and xxxiv-xlvii. 1908. On Mullerian mimicry and diaposematism. Trans. Entomological Soc. London, 1908: 559-583. Dixon, W. J., & F. J. Massey, Jr. 1957. Introduction to statistical analysis, second edition. McGraw-Hill Book Co., Inc., New York. 488 pp. Dobzhansky, Theodosius 1951. Genetics and the origin of species, third edition revised. Columbia University Press, New York. 364 pp. Eltringham, Harry 1916. On specific and mimetic relationships in the genus Heliconius. Trans. Entomologi- cal Soc. London, 1916: 104-148. Fisher, R. A. 1927. On some objections to mimicry theory; statistical and genetic. Trans. Entomologi- cal Soc. London, 75: 269-278. 1930. The genetical theory of natural selection. Clarendon Press, Oxford. 272 pp. 1958. The genetical theory of natural selection. Second revised edition. Dover Publica- tions, Inc., New York. 291 pp. Fleming, Henry 1960. The first instar larvae of the Heliconiinae (Butterflies) of Trinidad, W. I. Zoologica, 45: 91-110. Ford, E. B. 1953. The genetics of polymorphism in the Lepi- doptera. Advances in Genetics, 5: 43-87. Ford, H. D., & E. B. Ford 1930. Fluctuation in numbers, and its influence on variation in Melitaea aurinia, Rott. (Le- pidoptera). Trans. Entomological Soc. London, 78: 345-351. Fox, R. M. 1956. A monograph of the Ithomiidae (Lepi- doptera). Part 1. Bull. American Museum of Natural History, 111: 1-76. Goldschmidt, R. B. 1945. Mimetic polymorphism, a controversial chapter of Darwinism. Quarterly Review of Biology, 20: 147-164 and 205-230. Haldane, J. B. S. 1959. Natural selection. In: Darwin’s Biological Work, Some Aspects Reconsidered. Ed. by P. R. Bell. University Press, Cambridge. 343 pp. Herklots, G. A. C. 1961. The birds of Trinidad and Tobago. Collins, London. 287 pp. Hinde, R. A., & N. Tinbergen 1958. The comparative study of species-specific behavior. In: Behavior and Evolution. Ed. by Anne Roe and G. G. Simpson. Yale University Press, New Haven. 557 pp. Holling, C. S. 1961. Principles of insect predation. Annual Re- view of Entomology, 6: 163-182. Huheey, J. E. 1961. Studies in warning coloration and mimicry. III. Evolution of MUllerian mimicry. Evo- lution, 15: 567-568. 82 Zoologica: New York Zoological Society [48: 7 Jones, F. M. 1932. Insect coloration and the relative accept- ability of insects to birds. Trans. Entomo- logical Soc. London, 80: 345-386. Kaye, W. J. 1906. Notes on the dominant Mullerian group of butterflies from the Potaro district of British Guiana. Trans. Entomological Soc. London, 1906: 411-439. 1916. A reply to Dr. Eltringham's paper on the genus Heliconius. Trans. Entomological Soc. London, 1916: 149-155. Lack, David 1954. The natural regulation of animal numbers. Clarendon Press, Oxford. 343 pp. Linsley, E. G. 1959. Ecology of Cerambycidae. Annual Review of Entomology, 4: 99-138. Linsley, E. G., T. Eisner, & A. B. Klots 1961. Mimetic assemblages of sibling species of Lycid beetles. Evolution, 15: 15-29. Marshall, G. A. K. 1902. Five years’ observations and experiments (1896-1901) on the bionomics of South African insects, chiefly . . . mimicry and warning colours. Trans. Entomological Soc. London, 1902: 287-584. 1908. On diaposematism with reference to some limitations of the Mullerian hypothesis of mimicry. Trans. Entomological Soc. Lon- don, 1908: 93-142. Mayr, Ernst 1958. Behavior and systematics./n: Behavior and Evolution. Ed. by Anne Roe and G. G. Simpson. Yale University Press, New Haven. 557 pp. Michener, C. D. 1942. A generic revision of the Heliconiinae (Le- pidoptera Nymphalidae). American Mu- seum Novitates, 1197: 1-8. Morgan, Lloyd P. 1900. Animal behavior. Edward Arnold, Lon- don. 344 pp. Mostler, G. 1935. Beobachtungen zur Frage der Wespen- Mimikry. Zs. Morph. Oekol. Tiere, 29: 381-455. Moulton, J. C. 1908. Some principal mimetic combinations of tropical American butterflies. Trans. En- tomological Soc. London, 1908: 585-606. Muhlmann, H. 1934. In Modellversuch kiinstlich erzute Mimi- kry und ihre Bedeutung fur den “Nacbah- mer”. Zs. Morph. Oekol. Tiere, 28: 259- 296. Muller, Fritz 1877. The “Maracuja (or Passion-flower) butter- flies.” Stettin Ent. Zeit., 38: 492-496. Translated in Longstaff, G. B., 1912. But- terfly-hunting In Many Lands. Longmans, Green, and Co., London, pp. 651-654. 1879. Ituna and Thyridia; a remarkable case of mimicry in butterflies. (Translated by R. Meldola). Proc. Entomological Soc. Lon- don, 1879: xx-xxix. Muenscher, W. C. 1939. Poisonous plants of the United States. Macmillan Co., New York. Nicholson, A. J. 1927. A new theory of mimicry in insects. Aus- tralian Zoologist, 5: 10-104. 1954. An outline of the dynamics of animal populations. Australian Jour. Zoology, 2: 9-65. Pocock, R. I. 1911. On the palatability of some British insects, with notes on the significance of mimetic resemblances. Notes by E. B. Poulton. Proc. Zoological Soc. London, 1911: 809- 868. Poulton, E. B. 1907. The significance of some secondary sexual characters in butterflies. Proc. Entomologi- cal Soc. London, 1907: xl-xliii. Punnet, R. C. 1915. Mimicry in butterflies. University Press, Cambridge. 188 pp. Roth, L. M., & T. Eisner 1962. Chemical defenses of Arthropods. Annual Review of Entomology, 7 : 107-136. Schmidt, R. S. 1958. Behavioural evidence on the evolution of Batesian mimicry. Animal Behavior, 6: 129-138. Seitz, A. 1913. Subfamily: Heliconiinae. In Macrolepi- doptera of the World. The American Rho- palocera, 5: 375-402, Stuttgart. Sexton, O. J. 1960. Experimental studies of artificial Batesian mimics. Behavior. 15: 244-252. Sheppard, P. M. 1959. The evolution of mimicry; a problem in ecology and genetics. Cold Spring Harbor Symposia Quant. Biol. 24: 131-140. 1961. Some contributions to population genetics resulting from the study of Lepidoptera. Advances in Genetics, 10: 165-216. 1963. The genetics of mimicry. Proc. XYIth In- ternational Congress of Zoology, 4: 150- 156. 1963] Brower, Brower & Collins: Experimental Studies of Mimicry 83 Stichel, H„ & H. Riffarth 1905. Heliconiidae. Das Tierreicb, Lief. 22, 290 pp. SWYNNERTON, C. M. F. 1915. A brief preliminary statement of a few of the results of 5 years’ special testing of the theories of mimicry. Proc. Entomological Soc. London, 1915: 21-44. 1919. Experiments and observations bearing on the explanation of form and colouring, 1908-1913, Africa. Jour. Linnaean Soc. Zoology, 33: 203-385. Thorpe, W. H. 1956. Learning and instinct in animals. Methuen and Co., Ltd., London. 493 pp. Turner, J. R. G. & Jocelyn Crane 1962. The genetics of some polymorphic forms of the butterflies Heliconius melpomene Linnaeus and H. erato Linnaeus. I. Major genes. Zoologica, 47: 141-152. Varley, G. C. 1957. Ecology as an experimental science. Jour, of Ecology, 45: 639-648. Wallace, A. R. 1871. Contributions to the theory of natural se- lection. Second edition. Macmillan and Co., London. 384 pp. Windecker, W. 1939. “Euchelia jacobeae L. und das Schutz- trachten-problem.” Zs. Morph. Oekol. Tiere, 35: 84-138. Wright, S. 1932. The roles of mutation, inbreeding, cross- breeding, and selection in evolution. Proc. Sixth International Congress of Genetics, I: 356-366. 84 Zoologica: New York Zoological Society [48: 7: 1963] EXPLANATION Plate I Representatives of the species of butterflies of- fered to caged Silverbeak birds in the experimental studies of relative palatability and Mullerian mim- icry. The butterflies are arranged to elucidate the experimental procedure. From left to right, the ver- tical columns are: (1) various species of satyrids which served as standard edible insects (those illus- trated here are related species from various parts of South and Central America, by courtesy of the OF THE PLATE American Museum of Natural History); (2) seven species of models; (3) their respective mimics; (4) the generalization butterflies (see text for explana- tion). Note that the specimen 5th from the top in the 4th column bears the beak-marks of a bird on its wings. The models, mimics, and generalization butterflies illustrated were captured in the wild in Trinidad during 1961 and 1962. Some of the heli- coniine individuals are represented several times in the plate. (Approximately .4 natural size). BROWER, BROWER & COLLINS PLATE I Euptychta sp Hehconius sar_a_ Helicomus dons Aerauhs vantMae. EXPERIMENTAL STUDIES OF MIMICRY. 7. RELATIVE PALATABILITY AND MULLERIAN MIMICRY AMONG NEOTROPICAL BUTTERFLIES OF THE SUBFAMILY HELICONIINAE 8 A Morphological Study of Imagine Heliconiinae (Lep.: Nymphalidae) with a Consideration of the Evolutionary Relationships within the Group1,2 Michael Emsley Department of Zoology, Faculty of Agriculture, University of the West Indies, Trinidad (Plate I; Maps 1-17; Text-figures 1-153) [This paper is a contribution from the William Beebe Tropical Research Station of the New York Zoological Society at Simla, Arima Valley, Trinidad, West Indies. The Station was founded in 1950 by the Zoological Society’s Department of Tropical Re- search, under Dr. Beebe’s direction. It comprises 200 acres in the middle of the Northern Range, which includes large stretches of government forest re- serves. The altitude of the research area is 500 to 1,800 feet, with an annual rainfall of more than 100 inches. [For further ecological details of meteorology and biotic zones see “Introduction to the Ecology of the Arima Valley, Trinidad, B.W.I.,” by William Beebe, Zoologica, 1952, Vol. 37, No. 13, pp. 157-184], Contents I. Introduction and Acknowledgments .... II. Systematic Synopsis, with Special Refer- ence to Distribution Philaethria dido Dryadula phaetusa Agraulis vanillae Dione juno D. moneta D. glycera Podotricha euchroia P. telesiphe Dryas iulia Heliconius aliphera H. isabella H. numata H. doris H. wallacei H. melpomene 85 86 87 87 88 89 90 91 91 91 92 94 94 95 95 95 95 ’Contribution No. 1041, Department of Tropical Re- search, New York Zoological Society. 2This study has been supported by the National Science Foundation (G21071) (see p. 86). H. erato 95 H. sara 95 H. ricini 95 III. Key to the Trinidad Species 104 IV. Morphology 105 Methods of Morphological Study 105 Head: Head capsule 105 Mouthparts 105 Antennae 106 Thorax: Thoracic and axillary wing sclerites 106 Prothoracic legs 106 Meso- and meta-thoracic legs 106 Pretarsi 108 Wings 108 Venation and tracheation 108 Androconia and distribution 110 Abdomen: Female scent glands 118 Male genitalia 119 Female genitalia 121 Internals 124 V. Discussion 124 VI. Conclusions 128 VII. Summary 128 VIII. References 128 I. Introduction and Acknowledgments Research on the Heliconiinae by both ama- teur and professional lepidopterists . reached its first peak around the turn of the last century. The group was popular, not only because of the exhibition of brilliant colors which made for spectacular collections, but also because of a surge of interest in the biological problems posed by polymorphism and what has been interpreted as intra- and inter-generic mim- icry. 85 86 Zoolog ica: New York Zoological Society [48: 8 Jocelyn Crane, the Director of the New York Zoological Society’s Department of Tropical Re- search, has been responsible more recently for the promotion of a program of research on the Heiiconiinae which has included studies on rear- ing technique (Crane & Fleming, 1953), the morphology of the eggs, larvae and pupae (Fleming, 1960; Beebe, Crane & Fleming, 1960), larval and pupal behavior and biology (Alexander, 1961a, b), spectral reflectance of wings (Crane, 1954), imaginal behavior (Crane, 1955, 1957), occurrence and genetics of im- aginal polymorphism (Beebe, 1955; Turner & Crane, 1962; Sheppard, 1963), and on paya- bility and Mullerian mimicry (Brower, Brower & Collins, 1963). The purpose of this paper is to compare the morphology of the adult butterflies and estimate the proximity of the evolutionary relationships among them. It is fortunate that Trinidad has six of the seven genera recognized by Michener (1942a) and that the nine local species of Heliconius are drawn from nine of the twenty- one infra-generic groups erected by Stichel & Riffarth in 1905. H. Martin Brown3 is currently making a revision of Heliconius so the only species of that genus included in this study are the nine species that occur in Trinidad, though some aspects of H. telesiphe are considered as it appears to be biologically associated with Podotricha telesiphe. These boundaries have been defined to avoid overlap with subsequent publications on the genus Heliconius and to present a paper which will be complete for use in Trinidad. In the course of this work the collections of Heiiconiinae in the museums of the eastern United States, England and Paris were examined, and field work was undertaken in Colombia and eastern and western Ecuador as well as in Trini- dad. The support of the National Science Foun- dation and the University of the West Indies made possible the trips to North and South America. The author is grateful to Jocelyn Crane for stimulating interest in this topic, to Julie Emsley for the drawings, and to the trustees and staff of the British Museum (Natural History), the American Museum of Natural History, the United States National Museum, the Museum of Comparative Zoology at Harvard University, the Hope Department of Zoology at Oxford, the University Museum of Cambridge and the Paris Museum of Natural History, for study facilities and the loan of material. 3H. Martin Brown, Fountain Valley School, Colorado Springs, Colorado, U.S.A. II. Systematic Synopsis, with Special Reference to Distribution In 1827, Swainson (Philos. Mag. Ser. 2, 1:187) proposed a new family, the Nymphali- dae, one of whose constituent subfamilies was the “Heliconinae.” He limited the Heiiconiinae to Heliconius in the strict sense, though subsequent authors included firstly Eueides (e.g., Stichel & Riffarth, 1905) and later Michener (1942a) included species previously allocated to the gen- era Colaenis, Philaethria, Dione and Agraulis. The rather superficial characters given by Doubleday & Westwood (1846) and Stichel & Riffarth (1905) are not peculiar to the group nor do they allow the inclusion of genera other than Heliconius. Characters of value are, cell R of the lorewing (discal cell) always closed, the basal branch of Sc of the hindwing recurrent and unforked, androconia always present on two or more wing veins, odiferous glands developed between segments eight and nine in females. The larvae are typically nymphalid (Fracker, 1915) and feed on various species of Passiflora (Passi- floriaceae). The group has been given status varying from tribe (Zerny & Beier, 1936) to full family (Stichel & Riffarth, 1905), but when their char- acters are considered within the framework of the Nymphalidae, subfamily is the upper accept- able limit. Though primarily endemic to the neotropics, where they occur on both sides of the Andes and in the east extend as far as 35° South, they are also incursive in the Nearctic region and in ex- ceptionally warm summers may reach as far as 50° North, although 36° North is their normal limit. Their range also includes the Bahamas Islands, Bermuda, the Greater and Lesser Antilles and the Galapagos Islands. The maps not only reflect the distribution of the insects but also the itineraries of collectors. Most noticeable is the apparent dearth of Heii- coniinae from the savannas of the Matto Grosso and Golias of Brazil. This could be a real phe- nomenon due to the vegetation and climate, or could be due to inaccessibility to collectors, though there are a few localities within this area where Dryas iulia and Heliconius aliphera are known. Seaport localities are suspect as they may be only the ports of exit of collectors or collections. Personal experience in the Andes has shown that the mountain cities like Bogota, Quito and Ambarto are usually the localities of the hotels in which the collectors stayed and give no indication whether the insects were taken on the eastern or western slopes. In most cases the authentic localities are sparsely distributed and 1963] Emsley: Morphological Study of Imagine Heliconiinae 87 do not allow the boundaries of species or sub- species to be defined with accuracy. Lists of acceptable localities taken from specimens in the museums mentioned in the acknowledg- ments have been deposited with each museum. Important taxonomic papers for the group are Stichel (1903 and 1938), Stichel & Riffarth (1905), Neustetter (1929) and Michener (1942a). Philaethria dido (Clerck) (Text-figs. 4, 23, 44, 62, 87, 98, 107, 124, 142, 153; Map 1; PI. I, Fig. 5) Philaethria Billberg 1820, Monobasic, Enum. Ins. in Mus. Blbg., p. 77. Genotype: Papilio dido Clerck 1764, designated by Scudder 1875, Proc. Amer. Acad. Arts Sci., 10:248. — Metamandana Stichel 1907, Gen. Ins., fasc. 63, p. 6, pi. 1, figs. 1, 2, 3a and 3b. = Metamorpha (part) Hiibner 1818. Verz. bek- annt. Schmett., p. 43. Philaethria dido (Clerck 1764), as Papilio dido, leones, Sect. 2, Register pi. 30. This large black and green butterfly (see Seitz, 1913, pi. 84a) extends from 17° North in Guatemala through Central America to South America east of the Andes at lat. 28° South. Its apparent absence from the llanos of Ven- ezuela and the savannas of eastern Brazil is possibly real, for it normally inhabits the upper canopy and margins of rain forests. On the other hand it is easily overlooked, as it flies high and is very hard to catch. There are no records west of the Andes, which is surprising for though it is rarely found above 800 metres, it does occur in northern Colombia. There is a specimen in the M.C.Z. labelled “Cuba cl. Wright,” but though the species is alleged to have occurred in Hispaniola, Bates (1935) doubted its authen- ticity. However de la Torre y Callejas (1949) reported a specimen being seen in Havana province. The sexes are alike. Variation between specimens from any one locality is almost as great as between specimens from the extremities of its range, and moreover, even in life, the green ground color fades rapidly. It is presum- ably the capture of specimens of different ages which has led to the description of forms such as Metamorpha dido var. ostara Rober 1906 (Soc. Ent., 20: 177) from Cauca which is alleged to be pale and large, and Metamandana dido diatonica Fruhstorfer 1912 (Ent. Rdsch., 29: 14-15) from Honduras (B.M. 1937-285) which is alleged to be smaller, but neither of these can be regarded as good subspecies. There are, how- ever, two clearly distinguishable forms which are regarded here as subspecies, though there are data in museum collections which suggest that they can occur sympatrically. The known localities for each form are included on the dis- tribution map. More detailed and accurate data are required to clarify the position. There seem no good grounds for suggesting that P. dido and Victorina steneles form a mim- etic pair, for though in museum collections they are somewhat similar, in life their habitats rarely overlap, though their territory could be covered by a single avian predator. Their habits make each clearly recognizable to human observers. Philaethria dido dido (Clerck 1764) The typical form occupies the whole range of the species with the possible exception of some of the southern localities. Philaethria dido wernickei (Rober 1906) as Metamorpha wernickei, Soc. Ent., 20: 177. [B. M. 1937-285, Obidos], = Metamorpha dido pygmaleon Fruhstorfer 1912, Ent. Rdsch., 29:14. In this variety both sexes lack the rust-colored markings on the underside of the wings. It ap- pears to occur sympatrically with typical dido south of the Amazon and is possibly a genetic polymorph. It is unfortunate that no series of specimens is known from one locality, by one collector, which contains both forms. Museum collections do not normally warrant quantitative consideration, but the relative abundance of wernickei seems to increase towards the southern limits of the species and Hayward (1952) states that it is the only form known from north- ern Argentina, though there are Paris museum records of dido dido from near Rio de Janeiro and Rio Grande do Sul. The specimen in the Hope collection labelled “Bogota” is probably in error, for not only is the altitude excessively high but Dr. E. Schmidt-Mumm4, a contem- porary resident and experienced collector in Colombia, has never seen it. Dryadula phaetusa (Linnaeus) (Text-figs. 3, 24, 45, 69, 88, 94, 104, 106, 125, 145, 153; Map 2; PL I, Fig. 3) Dryadula Michener 1942, Monobasic, Amer. Mus. Novit. No. 1197, p. 4, figs. 5 and 10. Genotype: Papilio phaetusa Linnaeus 1758. = Colaenis Hiibner 1819 (part), Verz. bekannt. Schmett., p. 32. Dryadula phaetusa (Linnaeus 1758), as Papilio (nymphalis) phaetusa, Syst. Nat. (10 ed.) 1, p. 478. This large orange and black butterfly (Seitz, 1913, pi. 84c) extends from Mexico at 23° North, and Florida (Martin & Truxal, 1955) 4Dr. E. Schmidt-Mumm, Optometra, Bogota, Colom- bia. 88 Zoological New York Zoological Society [48: 8 through Central America to South America, where on the eastern side of the Andes it extends as far as 35° South and on the western side at least as far south as Guayaquil. Over its whole range it is very local, rarely occurring above 800 metres and seems to prefer open damp low-lying land. Its absence from the Amazon Basin and the dry savannas of eastern Brazil is not unexpected in view of its ecological preferences elsewhere, but the full extent of its range may not be known yet, on account of its normally restricted localities, fast erratic flight and the paucity of collections from some areas. Males can be distinguished from females by the more orange ground color and the more intense and precise dark markings. Variation within specimens from any one locality is nearly as great as the variation within the whole range of the species, so no good geographical sub- species can be distinguished. This variability has in the past led to the description of such forms as D.p. stupenda Stichel 1907 (as Colaenis phaetusa forma stupenda, Gen. Ins. fasc. 63, p. 13) from Panama, which has a particularly red ground color, and deleta ($) and lutulenta (?) which were described from Paraguay by Stichel in the same paper as having more dull coloration. Agraulis vanillae (Linnaeus) (Text-figs. 5, 38, 39, 61, 68, 81, 97, 108, 132, 151, 153; Map 3; PI. I, Fig. 2) Agraulis Boisduval & Le Conte 1836, Monobasic, Hist. Gen. Lep. Chen. Amer. Sept., p. 142-43. Genotype: Papilio vanillae Linnaeus 1758, = Dione Hiibner 1818 (part), Verz. bekannt. Schmett., p. 31. Agraulis vanillae (Linnaeus 1758), as Papilio (nymphalis) vanillae Syst. Nat. (10 ed.), 1. p. 482. In exceptionally warm years this orange and black butterfly (Seitz, 1913, pi. 84f) ranges from British Columbia at lat. 50° North, but more normally from 36° North on both sides of the continent, through the southern States to Central America, and through the Bahamas and the Greater and Lesser Antilles to South Amer- ica. It reaches 33° South on the eastern side of the Andes and at least as far as Lima (12° South) on the western side. It seems limited to altitudes below 1,500 metres. There are no records from the savannas of eastern Brazil in spite of the fact that elsewhere it is a common and conspicuous butterfly which is easy to catch. It usually inhabits forest margins and open scrub or young secondary growth forests. The review of the subspecies by Michener (1942b) is accepted and followed here. Subspecies (1) Agraulis vanillae vanillae (Lin- naeus 1705), as Papilio vanillae figured in Merian, Metam. Ins. Surinam, p. 25, pi. 25. The typical subspecies occurs from eastern Panama throughout the whole of South America east of the Andes as far as about 20° South and it also occurs in Trinidad, Tobago, Barbados, Grenada, the Grenadines, St. Vincent and St. Lucia, where it grades into A. v. insular is, which is the characteristic form of the Greater and northern Lesser Antilles. It has also been re- corded from Bermuda, but since insularis is naturally nearer, it was probably transported on a ship or plane. Subspecies (2) Agraulis vanillae insularis Mayn- ard 1889, as Agraulis insularis Contrib. Sci. Philad. Acad. Sci., 1 :89. With the type locality “Bahama Island,” the range of this variable subspecies includes Nassau, Andros and New Providence (Michener 1942b), North and South Bimini (Rindge 1952), Exuma Cay, Wandereck Well Cays, Staniard Cay, Little and Great Farmers Cay, Derby Island, Cat Island, Great Inagua, West Caicos, Grand Turk, Cay 3.5 miles S.W. of N. Caicos, Maninguana Island, Crooked Island, Long Island, San Salvador Island, Fortune (Long Cay), Fish Cay, Dead Mans Cay, Eleu- thera Island, Berry Island, Albow Cay, Abaco Cay, Great Abaco and Grand Bahama (Rindge 1955) ; Cuba, Jamaica, Grand Cayman, Cayman Brae, Little Cayman, Hispaniola, Puerto Rico, St. Croix, St. Thomas, St. Bartholomew, St. John, St. Kitts, Montserrat, Anguilla, Guade- loupe, Dominica and Martinique. This form can be distinguished with certainty from typical vanillae from the southeastern Antilles only v/hen long series of specimens are compared. It may not breed on all islands from which it is recorded, for this butterfly is capable of consid- erable flights over water, as evidenced by a British Museum specimen taken at sea south of Panama at lat. 6°44' N. by long. 79°26' W., that is 75 miles from the nearest land. It is in- teresting to notice how A. vanillae, though vari- able in the Antilles, has not differentiated into forms comparable with those of Dryas iulia. Subspecies (3) Agraulis vanillae nigrior Mich- ener 1942, Amer. Mus. Novit. No. 1215, p. 7. This subspecies occurs in the southeastern United States and in exceptional summers as far north as New York, but usually from North Carolina through South Carolina, Georgia, Alabama to Florida and its Keys, and westward through Tennessee, Mississippi, Louisiana, Arkansas and Missouri where it intergrades with incarnata. The distinction between the Greater Antillean insularis is clear, even though 1963] Emsley: Morphological Study of Imagine Heliconiinae 89 separated by only 75 miles of water. De la Torre y Callejas (1949) records a specimen taken from Cuba in 1945, but which is surely an immigrant. Gunder (1929, Bull. Brooklyn Ent. Soc. (n. ser.) 24: 327, p. 31, fig. 7) described a melanic variety from Ontario as hewlettae. The life history in the southern States has been studied by Randolph (1922). Subspecies (4) Agraulis vanillae incarnata (Riley 1926), as Dione vanillae incarnata, Entomolo- gist, 59:243. This subspecies, whose type locality is Dur- ango City, Mexico, has in exceptional years been taken as far north as British Columbia and Wisconsin, but its more normal distribution is from California at lat. 37° North through Ariz- ona, New Mexico and Texas to Mexico and Cen- tral America as far as Panama. Wright (1896) maintained that its range was extended north through California when the Southern Pacific Railroad was opened in 1885. Gunder described a number of aberrant melanic varieties under the infra-subspecific names comstocki (1925, Ent. News Philad., 36: 5, pi. 1, fig. T), fumosus (1925, Ent. News Philad., 38: 137, pi. 2, fig. 9) and margineapertus (1928, Canad. Ent. 60: 163, pi. A, fig. 3a) , all from Los Angeles. Subspecies (5) Agraulis vanillae forbesi Mich- ener 1942, Amer. Mus. Novit. No. 1215, p. 3. This subspecies with the type locality of Lima forms the southern limit of the species on the western slopes of the Andes and in northwestern Colombia it grades into typical vanillae. Subspecies (6) Agraulis vanillae galapagensis Holland 1889, in Howard, Proc. U. S. Nat. Mus., 12:194. This distinct subspecies is confined to the Galapagos Islands from which it has been re- corded on Chatham (type locality), Albemarle, James, Charles and Indefatigable Islands. Some specimens of forbesi are very similar in size, pattern and color but differ in that the forewing spots which lie antero-distal to the discal cell are not contiguous, as they are in galapagensis. Doubtless it is from a population on the Peruvian coast that the Galapagos Islands have been colonized. Subspecies (7) Agraulis vanillae maculosa (Stichel 1907), as Dione vanillae maculosa, Gen. Ins. fasc. 63, p. 18. This subspecies is characteristic of the south- eastern regions of the Andes and occurs as far south as Uruguay and northern Argentina. It has also been recorded from Chile at Limache but this seems very unlikely to be natural, for it is on the western slopes. Towards the north in Brazil this form grades into typical vanillae but in the northwest towards the tributaries of the Upper Amazon, though there are few records, it seems to grade through catella to lucinia. The form superargentata described by Giacomelli (1925, Rev. Chilen. Hist. Nat., 29: 228) has not been seen. Subspecies (8) Agraulis vanillae lucinia C. and R. Felder 1862, as Agraulis lucinia Wein. Ent. Monatschr., 6:110. The status of this very distinct form is still in doubt, for though it appears to be confined to the tributaries of the Upper Amazon at a higher altitude than typical vanillae there is in- sufficient field data to be sure that they do not occur sympatrically. Apart from color and pat- tern, lucinia is morphologically indistinguishable from other forms of vanillae and the existence of individuals intermediate in color and pattern like catella demonstrates that it is not completely reproductively isolated. The variable form catella was described by Stichel in 1907 (as Dione vanillae catella, Gen. Ins. fasc. 63, p. 18) and is known only by a small number of speci- mens. Agraulis vanillae varies over its range prin- cipally in size and the development of the dark markings, and considering the substantial sea- sonal variation in specimens from any one lo- cality and the similarity of trend in specimens from localities with similar climatic conditions the main causes of these differences may be environmental, though there is no experimental evidence. The form lucinia differs substantially from the remainder of the subspecies in the con- solidation of the dark markings, and the reduc- tion of silver spots which produces an effect very similar to that of Dione juno, with which it is grossly sympatric. There is no evidence that there is a mimetic association between A. lucinia and D. juno though the similarity is re- markable. It is unfortunate that the range of lucinia is in one of the least-collected areas of the continent and it is not known whether lucinia in the field flies with either D. juno or other forms of vanillae. However, the differen- tiation of lucinia is complex enough to assume that it is a genetic variety and not an environ- mental form. Dione Hiibner Dione Hiibner 1818, Verz. bekannt. Schmett. p. 31. Genotype: Papilio juno Cramer 1779, designated by Scudder, 1875, Proc. Amer. Acad. Arts Sci., 10:157. Dione juno (Cramer) (Text-figs. 11, 34, 35, 58, 63, 84, 96, 109, 129, 148, 153; Map 4; PI. I, Fig. 1) Dione juno (Cramer 1779), as Papilio juno, Pap. Exot., 3:38, pi. 215, figs. B and C. 90 Zoologica: New York Zoological Society [48: 8 This orange and black butterfly (Seitz, 1913, pi. S4e) occurs from Mexico at lat. 28° North through Central to South America, where on the east of the Andes it extends as far as lat. 35° South and on the west as far as southern Peru at lat. 17° South. It is allegedly known from His- paniola and there is one unconfirmed record from Cuba (Hall, 1925). In the Lesser Antilles it is known only from the islands south of and including Martinique. The sexes differ in that the females are usually larger. In habits, habitats and. continental distribution it is very similar to Agraulis vanillae. Subspecies (1) Dione juno juno (Cramer 1779), as Papilio juno (loc. cit.). The typical subspecies occurs in South Amer- ica and is generally distributed from north- western Colombia, where it grades to the north into huascama, throughout the whole of South America east of the Andes as far as 35° South, and includes the islands of Trinidad, Tobago, Grenada, the Grenadines, St. Vincent, St. Lucia and Martinique. Throughout its range it is very uniform and the sexes are similar. Hayward (1931, Rev. Soc. Ent. Argent., 4: 40) described suffumata, which has not been seen. It is doubt- ful if it normally occurs above 1,500 metres. The early stages have been studied by d’Almeida (1944). The absence of records from the savan- nas of eastern Brazil is probably real, for it is usually a common insect where it occurs at all and is easy to catch. Subspecies (2) Dione juno huascama (Reakirt 1866), as Agraulis huascama, Proc. Acad. Nat. Sci. Philad., pp. 243-244. This subspecies ranges from northern Mexico at lat. 28° North through Central America to Colombia where east of the Magdalena Valley it grades into juno. It differs from the typical form in that it is larger, usually paler, with the dark border to the posterior margin of the hindwing spotted with ground color, and is more variable. Sexual dichromatism is pronounced, the females being lighter in color, and with the dark markings less precise. Rarely above 1,500 metres. Subspecies (3) Dione juno andicola (Bates 1864), as Agraulis andicola, Journ. Ent., 2:187. This subspecies extends from western Colom- bia along the western slopes of the Andes below 2,200 metres, through Ecuador to southern Peru at lat. 17° South. It differs from huascama prin- cipally in its smaller size, and in that the dark markings of both sexes are paler. The early stages have been studied by Brown (1944). A specimen from Lima shows typical juno mark- ings but may have been taken on the eastern slopes. The form miraculosa described by Hering from Huacho, Peru (1926, Deutsch Ent. Zeit. Ivies, 40: 196-201, figs. 2 & 5), has not been seen. Dione moneta Hiibner (Text-figs. 9, 37, 60, 82, 111, 128, 149, 153; Map 5) Dione moneta Hiibner (& Geyer) 1825, figured in Samml. Exot. Schmett. 2, pi. 20, figs. 1 & 2. This orange and black butterfly (Seitz, 1913, pi. 84e) ranges from Mexico at lat. 25° North through Central and South America east of the Andes as far as 30° South. On the western slopes it occurs at least as far as 3° South. The sexes are similar. Subspecies (1) Dione moneta moneta Hiibner 1825 (loc. cit.). The typical subspecies forms the southern extremity of the range extending northwards from latitude 30° South as far as about 20° South, where in Bolivia it grades into butleri, from which it may be distinguished by its smaller size and medium sized spots of ground color on the posterior border of the hindwing. It has not been recorded from central or eastern Brazil so it appears to be confined to the eastern slopes and foothills of the Andes. The early stages have been studied by Brown (1944). Subspecies (2) Dione moneta butleri Stichel 1907, Gen. Ins., fasc. 63, p. 19. This form intergrades with moneta around 20° South and extends northwards along the eastern slopes of the Andes into poeyii. Speci- mens taken from the western slopes of the Andes are intermediate between butleri and poeyii in that they are medium sized but have the spots on the posterior border of the hindwing inter- mediate between the small ones characteristic of butleri and the large ones of poeyii. There is a record by Wallengren (1863) of a specimen from the Galapagos Islands, but even if correct then it is certainly not established there now. Subspecies (3) Dione moneta poeyii Butler 1873 as Dione poeyii, Ann. Mag. Nat. Hist. (ser. 4), 12:227. This northern subspecies ranges from about lat. 27° North, where on occasions it has been recorded from Texas, through Mexico and Cen- tral America to Panama. It can be distinguished by the larger size and by the very large spots of ground color on the posterior border of the hindwing. Over-all there is a north-south cline of de- creasing size and darkening of posterior border to the hindwing, a tendency which is reversed slightly at the southern extremity of the range. Hall (1921) is of the opinion that it does not often occur below 1 ,000 metres in Central America and it has certainly attained 3,500 metres in Costa Rica. From locality data and 1963] Emsley: Morphological Study of Imagine Heliconiinae 91 field observations this may be true over its whole range and explains the similarity between the forms taken on both sides of the Andes. The map shows only the gross range within which it may be expected to occur, for museum local- ities are sparse. Dione glycera (C. & R. Felder) (Text, figs. 10, 36, 59, 64, 83, 110, 127, 150, 153; Map 4) Dione glycera (C. & R. Felder 1861), as Agraulis glycera Wein. Ent. Monatschr., 5:102-103. = Dione moneta forma gnophota Stichel 1907, Gen. Ins., fasc. 63, p. 30, pi. 1, fig. 4. This orange and black butterfly (Seitz, 1913, pi. 84f) occurs in South America from western Venezuela along the eastern slopes of the Andes through Ecuador, Peru and Bolivia to northern Argentina (Hayward, 1952). This is an upland species and rarely descends below 1 ,000 metres (Hall, 1921) and there has been no differentia- tion into subspecies. The sexes are similar. Pre- sumably due to the transposition of the plates in Seitz (1913) with those of D. moneta, a con- siderable quantity of museum material has been incorrectly identified and naturalists’ field notes are difficult to assign to the correct species. The map indicates the gross range within which gly- cera has been found; it does not necessarily occur everywhere within it, for museum data are scanty. Podotricha Michener Podotricha Michener 1942, Amer. Mus. Novit. No. 1197, p. 3, figs. 2, 11. Genotype: Colaenis euchroia Doubleday 1847, = Colaenis Hiibner 1819 (Part), Verz. bekannt. Schmett., p. 32. The distribution of the species of this genus is handicapped by the paucity of authentic localities, for many data labels only reveal the headquarters of collectors and not the sites of capture. Suspect localities are indicated as such on the maps, which contain all the indentifiable localities of specimens in the museums visited, together with information communicated by Cornell University. Both species seem local and solitary. The food plants and immature stages are unknown. They are upland butterflies, but they do not reach the higher peaks and are probably limited to between 1,200 and 2,400 metres. Of the approx- imately 150 specimens examined, less than 5% were females. There is no sexual dichromatism, so presumably the habits of the females prevent them from coinciding with the paths of collec- tors. The terrain inhabited by these species is rugged and precipitous, so the sites of the food plants may be quite inaccessible to the general collector, though the males would be taken feed- ing on flowers after the females had retired to seek sites for oviposition. Podotricha euchroia (Doubleday) (Text-figs. 8, 48, 65, 86, 112, 130, 141, 143, 153; Map 6) Podotricha euchroia (Doubleday 1847), as Colaenis euchroia, Gen. Biurn. Lep. p. 149, pi. 20, fig. 3. This butterfly (Seitz, 1913, pi. 84c), which has a yellow or orange ground color with black markings, occurs in South America on the Andean highlands from just inside the Venezu- elan border in the Cord de Merida, through Colombia and Ecuador to Peru at lat. 5° South. The locality “Cuzco” on two specimens in the Paris Museum is suspect, for it is 800 miles south of the nearest other record. A specimen in the Hope collection labelled “Para” is almost cer- tainly in error. The sexes are alike. Subspecies (1) Podotricha euchroia euchroia (Doubleday 1847) (loc. cit.)- This subspecies has a deep orange ground color and occurs only in the northern half of the range of the species. In the Cauca Valley the ground color may be more yellow and was described as caucana by Riley (1926, Entomolo- gist, 59: 242), though it seems to occur sym- patrically with the typical form and may be a seasonal variety. Subspecies (2) Podotricha euchroia mellosa (Stichel 1906), as Colaenis euchroia mellosa, Ins. Borse, 23:208. This subspecies occupies the southern half of the range and has a straw-colored ground color with more extensive dark markings than the typical form. The transverse light yellow bar on the hindwing is white at the base, though this is variable and may be white along almost its whole length, a form to which the name stram- inea was given by Riley ( 1926, ibid) . As mellosa and straminea do not seem to be geographically or ecologically isolated, it is possible they also are seasonal forms. The only geographical feature separating the distribution of the subspecies euchroia and mellosa is the valley of the Rio Patia, which does in fact separate them exactly. It is unfortunate that not only are there few museum specimens available for study, but of those there are even fewer which have precise locality data. Field observations suggest that this is a species pre- ferring altitudes in the range 1 ,000-2,000 metres and such records as Guayaquil are probably ports of embarkation and not sites of collection. Podotricha telesiphe (Hewitson) (Text-figs. 7, 26, 47, 66, 113, 131, 153; Map 7) 92 Zoologica: New York Zoological Society [48: 8 Podotricha telesiphe (Hewitson 1867), as Colaenis telesiphe, Trans. Ent. Soc. Lond. (Ser. 3), 5:564. This dark brown butterfly (Seitz, 1913, pi. 84d) with orange markings on the forewings occurs on the eastern slopes of the Andean high- lands from northern Ecuador to Bolivia at 17° South. The sexes are similar. Two forms may be distinguished by the color of the transverse band on the upper surface of the hindwing. Subspecies (1) Podotricha telesiphe telesiphe (Hewitson 1867) ( loc . cit.). This subspecies, which has a white transverse band on the hindwing, occupies the southern part of the range from about lat. 2° South to 18° South. It is uniform over its range and occurs sympatrically with Heliconius telesiphe telesiphe Doubleday 1847 (Map 8), which is very similar in appearance. Subspecies (2) Podotricha telesiphe tithraustes (Salvin 1871), as Colaenis tithraustes, Ann. Mag. Nat. Hist. (Ser. 4), 7:415. This form may be distinguished from P. t. tele- siphe by the bar on the hindwing, which is yellow instead of white. It occurs between lat. 1° North and 2° South, a range it shares with Heliconius telesiphe sotericus Salvin 1871 (Map 8), which also has the bar of the hindwing yellow. Many museum specimens have the names of the two forms of P. telesiphe transposed, presumably be- cause Seitz (1913) made this error and subse- quent workers have overlooked the correction on pages 1134 and 1 139 of his text. In the collec- tion of the University of Central Ecuador in Quito there are some specimens of P. telesiphe from Puyo which have the transverse bar cream. These are the only known intermediates between the two color forms and Puyo is on the mutual boundary of their ranges. There is a specimen of H. t. telesiphe in the British Museum labelled “Bogota” and a specimen of H. t. sotericus in the British Museum (Tring) labelled “British Gui- ana,” both of which are certainly in error. There are no biological data available on the distastefulness of either P. telesiphe or H. tele- siphe, and though this probable example of inter- generic mimicry has been known for many years, a full understanding seems no nearer. The sig- nificant features are that these two genera are not very closely related, yet not only are these species generally similar in appearance but the two color forms of each have an identical distri- bution and, according to field reports, fly togeth- er. There are no conspicuous geographical fea- tures separating the two subspecies of P. tele- siphe and H. telesiphe but east of the Gulf of Guayaquil the Andes are invaded by deeper east-west valleys than elsewhere, though the minimum altitude is still within the normal range of the two species. Dryas iulia (Fabricius) (Text-figs. 1, 2, 6, 22, 25, 42, 43, 46, 67, 79, 85, 89, 95, 99, 114, 126, 144, 153; Map 9; PI. I, Fig. 4) Dryas Hiibner 1807, Monobasic, figured in Samml. Exot. Schmett., 1, pi. 43, 4 figs. Genotype: Papilio iulia Fabricius 1775, desig- nated by Hemming, 1934, Entomologist, 67:156. = Colaenis Hiibner 1819, (Part), Verz. bekannt. Schmett., p. 32. Genotype: Papilio iulia Fabricius 1775, desig- nated by Scudder 1875, Proc. Amer. Arts Sci., 10:146. Dryas iulia (Fabricius 1775), as Papilio iulia, Syst., Ent., p. 509. This bright orange butterfly with black mark- ings on the upper surface of the wings (Seitz, 1913, pi. 84b) occurs from Florida and eastern and western Mexico at lat. 30° North, through the Bahamas, the Greater and Lesser Antilles and Central America to South America. East of the Andes it extends to 35° South, and on the western slopes it has been recorded as far south as Loja (4° South). It is doubtful if it occurs much above 1,500 metres, though it occupies very varied habitats below this altitude. It is a common and conspicuous butterfly which is fair- ly easy to catch, both in flight and during its habit of resting in the sun on damp earth. Throughout its range it has become differenti- ated into geographical subspecies which differ in their ground color, the intensity and extent of the black markings and in the distribution of the androconia on the forewing veins of males. The sexes can be distinguished by the presence of a second dark bar on the forewings of females and the generally more diffuse nature of the pattern. Subspecies (1) Dryas iulia iulia (Fabricius 1775), as Papilio iulia, (loc. cit.). The typical subspecies ranges from the east- ern and western coasts of Mexico at lat. 30° North through Central America to South America where, on the eastern side of the Andes, it extends throughout the whole of the Amazon Basin and Brazilian savannas and is generally distributed as far as 35° South. It also occurs in Trinidad and Tobago. The ground color when fresh is a rich orange with intense dark markings on the upper surface of the wings, though spec- imens from Central America and Mexico are lighter in color and have less distinct markings. The androconia on the forewings of males are present only on veins Cula, Culb and 1A. Subspecies (2) (?) Dryas iulia moderata (Stichel 1907), as Colaenis iulia delila forma moderata, Gen. Ins., fasc. 63, p. 12. 1963] Emsley: Morphological Study of Imagine Heliconiinae 93 Originally described from a male from Hon- duras, this pale, and in males almost immaculate, form occurs in eastern and western Mexico through Central America to the western slopes of the Ecuadorian Andes at least as far south as Loja. Grossly, its range appears to overlap that of the typical form in Mexico and Central America, but in southwestern Colombia and western Ecuador it replaces it completely and is subject to a small amount of variation. The distri- bution of androconia is similar to that of typical iulia. Museum locality data cannot be treated quantitatively and are not always reliable, but the wide range of moderata and its apparent overlap with iulia suggests it is neither ecolog- ically isolated nor is it the result of environ- mental effects on the larvae, though there is no experimental evidence to indicate whether mod- erata characters are heritable or not. The most plausible explanation is that the immaculate form is typical of the southwestern extremities of the range of the species and the genes or loss of genes responsible for the immaculate appearance have spread into the northwest where they form a proportion of a polymorphic population. The similarity in appearance, habits and habi- tat between Dryas iulia and Heliconius aliphera has been noticed for many years. Though the range of H. aliphera is more restricted in the north, elsewhere they almost invariably fly to- gether. The association of D. i. moderata with an almost equally immaculate form of H. ali- phera, which is known only from sympatric localities, has suggested a mimetic association but little is known about their relative payabili- ties. D. iulia titio (Stichel 1907) (as Colaenis iulia titio, Gen. Ins., fasc. 63, p. 12) is an al- legedly fiery red form from Youngas de la Paz, Bolivia, which occurs sympatrically with the typical form and from which it cannot be separ- ated on the museum specimens (Riley 1926) . Subspecies (3) Dryas iulia cillene (Cramer 1779), as Papilio cillene, Pap. Exot., 3:38, pi. 215, figs. D and E. This subspecies from Florida and the neigh- boring Keys is more pale than the typical form and has the dark markings reduced. The an- droconia of males are prominent on forewing veins Cula, Culb, and 1A but on some speci- mens from the Keys there are small numbers on one or more of the veins Ml, M2 and M3. The locality data of Cramer’s original speci- men (“Dutch Guiana”) is certainly in error, for his figures, which are without description, are similar to the Cuban forms, but variation within the populations on neighboring islands could include this type. Had Cramer figured the males more accurately and included the black andro- conia on the forewing veins, then these would have assisted in deducing the exact locality of his specimens. It is not known whether the type is still in existence or not, so Stichel’s allocation of the name nudeola to the Cuban form must stand until reference to the type can prove Cramer’s original specimen was also Cuban. Subspecies (4) Dryas iulia nudeola (Stichel 1907), as Colaenis iulia cillene forma nudeola, Gen. Ins., fasc. 63, p. 12. This subspecies from Cuba, the Isle of Pines and Grand Cayman is similar to cillene but in males the forewing bar is represented by a pair of dark spots which are, or are just not, in con- tact. In the dozen specimens examined from east- ern Cuba the forewing androconia are abundant on veins Ml, M2, M3, Cula, Culb and 1A. Subspecies (5) Dryas iulia carteri (Riley 1926), as Colaenis iulia carteri, Entomologist, 59:240, pi. 2, fig. 1 [B.M. RH. 9223 and 4, Nassau]. This subspecies from the Bahamas Islands is similar to cillene in color and in the extent of the dark markings of the forewings, which in males are clearly separate. Androconia are present on forewing veins Ml, M2, M3, Cula, Culb and 1A, a feature shared with nudeola, but some specimens from the western islands show only traces of androconia on the median veins, in which respect they grade into cillene from Flor- ida. It has been taken from Nassau, Long Island, Cat Island, Eleuthera Island, Berry Island and New Providence (Rindge, 1955). Subspecies (6) Dryas iulia delila (Fabricius 1775), Syst. Ent., p. 510. First figured by Sloane, 1725, Nat. Hist. Jam. IT, p. 215, pi. 239, figs. 21, 22, as Papilio major. The males of this exclusively Jamaican sub- species are entirely immaculate above and are similar to extreme examples of moderata, but can be distinguished by the lighter and broader wings which lack the narrow black margin, and by the very heavy investment of androconia on forewing veins Ml, M2, M3, as well as on Cula, Culb and 1A. Subspecies (7) Dryas iulia hispaniola (Hall 1925), as Colaenis iulia hispaniola, Entomolo- gist. 53: 186. This subspecies from Hispaniola is similar to nudeola but has a slightly greater development of the dark markings, so that in males the fore- wing spots are fully confluent, making an incom- plete bar. From the small number of specimens available, it seems there is variation in the dis- tribution of androconia, for some have them strongly developed on six forewing veins whereas the others have the three more anterior veins only sparsely invested. 94 Zoologica: New York Zoological Society [48: 8 Subspecies (8) Dryas iulia juncta Comstock 1944, Sci. Surv. Puerto Rico, 12:441, figs. This subspecies from Puerto Rico and St. John is similar to hispaniola except that the dark mark- ings are more fully developed and the forewing is traversed by a complete, through irregular, bar. The androconia of the forewing seem to be con- fined to the posterior three veins, though this observation is based on an examination of only three specimens. Subspecies (9) Dryas iulia warneri (Hall 1936), as Colaenis julia warneri, Entomologist, 69:276. [B.M. 1936-736, St. Kitts], This form from St. Kitts has not been exam- ined. Subspecies (10) Dryas iulia dominicana (Hall 1917), as Colaenis julia var. dominicana, En- tomologist, 50:161. This subspecies from Dominica and Guade- loupe has a ground color similar to that of the Greater Antillean forms but has the bar of the forewing complete and forewing is deeper than in any of the other subspecies. The forewing androconia are well developed on Ml, M2, M3, Cula, Culb and 1A. Subspecies (11) Dryas iulia lucia (Riley 1926), as Colaenis iulia lucia, Entomologist 59:241, pi. 2, fig. 4. [B.M. RH. 10115, St. Lucia], This subspecies from St. Lucia and Martini- que has a rich red ground color similar to that of the southern mainland forms, but with reduced dark markings so the forewing bar is represented only by two distinct small spots. It appears to differ also from dominicana in the absence of androconia on the median veins of the forewing, though this observation is based on an examina- tion of only three specimens. Subspecies (12) Dryas iulia framptoni (Riley 1926), as Colaenis iulia framptoni, Entomolo- gist, 59:241, pi. 2, fig. 5, [B.M. RH. 10116-7, St. Vincent], This last subspecies from St. Vincent, Barba- dos (where it is probably a migrant), Grenada and the Grenadine Islands has the upper side ground color, dark markings and distribution of androconia similar to the mainland iulia, but the underside is a more dark purplish brown. Subspeciation in the area around Cuba, Flor- ida, the Bahamas Islands and Hispaniola is in a very incipient state and a long series of speci- mens from each locality would be necessary to distinguish them with certainty. Though males from all localities have androconia on the two most anterior veins of the hindwing, there seems to be a center in this area of forms which have androconia on six forewing veins too, a feature found elsewhere only in specimens from Guade- loupe and Dominica, Outside these localities fore- wing androconia occur only on the three poster- ior veins of the forewing (Cula, Culb and 1A), though in marginal areas like Florida Keys, eastern Bahamas and Hispaniola they may occur sparsely on the three more anterior veins (Ml, M2 and M3 ) . The explanation of the occurrence of the androconia on six forewing veins in Dom- inica and Guadeloupe is handicapped by a short- age of specimens, but if the absence of known intermediates on the neighboring islands is valid it suggests that the populations are more isolated on the eastern Caribbean Islands than elsewhere, a suggestion that is corroborated by the higher degree of subspeciation in that region. The con- trast in the appearance of specimens from the eastern and western slopes of the Andes demon- strates that the mountains form a barrier that can only be circumvented round the spurs of north- ern Colombia. Elsewhere the lowest pass that could offer an east-west corridor is 2,500 meters high, that is, nearly 1,000 meters above the high- est altitude Dryas is normally known to inhabit. Heliconius Kluk Heliconius Kluk 1802, Zwierz. Hist. nat. pocz. gospod., 4:82. Genotype: Papilio charitonia Linnaeus 1767. Designated by Hemming, 1933, Entomologist, 66:223. The only species of Heliconius included in this paper are those that occur in Trinidad, and as the genus is to be the subject of a later publication the detailed distribution of subspecies and other forms will be deferred and no nomenclatorial or taxonomic changes will be suggested. Heliconius aliphera (Godart 1819) (Text-figs. 20, 41, 57, 77, 122, 133, 134, 147, 153; Map 10; PL I, Fig. 7) This orange and black butterfly (Seitz, 1913, pi. 80a) is very similar to a small Dryas, with which it flies over almost all of its range. The variations in the intensity and extent of the black markings parallel those of Dryas, with which they occur sympatrically. In Central America there are a number of closely allied forms which may or may not be conspecific. Heliconius Isabella (Cramer 1781) (Text-figs. 19, 40, 56, 78, 92, 101, 123, 135, 146, 153: Map 11; PI. I, Fig. 6) Though fairly constant in Trinidad, this black and orange butterfly (Seitz, 1913, pi. 80d) is variable elsewhere and without a more detailed study it is difficult to define its limits with ac- curacy. Its habitat includes both forest and forest margins, so the absence of records from the llanos of Venezuela and the savannas of eastern Brazil is probably real. 1963] Emsley: Morphological Study of Imagine Heliconiinae 95 Heliconius numata (Cramer 1780) (Text-figs. 15,27, 49,71,90, 116, 136, 153; Map 12; PI. I, Fig. 9) This yellow and/or orange and black butter- fly (Seitz, 1913, pi. 72), which is frequently con- sidered to be a Mullerian mimic of members of the Danaidae and Ithomiidae, occurs in Trinidad in two polymorphic forms, one with a predomin- antly orange ground color, and one with a greater proportion of yellow, which is particularly no- ticeable on the hindwing. On the mainland the diversity of numata, or its very close relatives, is extremely great, so pending a revision of the genus the distribution map can only include those forms which are similar to those of Trinidad. It seems likely that further study will show that many of the named varieties and geographical forms will subsequently be shown to be conspeci- fic with numata, and its range will include the western slopes of the Andes and more southerly regions of eastern South America. Heliconius doris (Linnaeus 1764) (Text-figs. 13, 29, 52, 72, 117, 139, 153; Map 13; PI. I, Fig. 14) This black and yellow butterfly (Seitz, 1913, pi. 77c) is known to be polymorphic, both in Trinidad and elsewhere, and commonly exhibits blue, red or green on the hindwing. It is a forest butterfly and unlikely to occur in the savanna areas. Heliconius wallacei Reakirt 1862 (Text-figs. 12, 28,50, 70,91, 115, 138, 153; Map 14; PI. I, Fig. 13 This blue, black and yellow forest butterfly (Seitz, 1913, pi. 77e) is relatively constant over its whole range, which is similar to that of H. sara, with which it frequently flies. There is a similarity also in that in some localities there is a delicate white margin to the posterior border of the hindwings. Specimens are known from diverse localities within the range of the species in which the yellow markings are replaced by white. Heliconius melpomene (Linnaeus 1702). (Text-figs. 14, 30,51,73, 100, 118, 137, 153; Map 15; PI. I, Fig. 8) In Trinidad this butterfly is monomorphic and is black with a broad red patch just distal to the center of each forewing (Seitz, 1913, pi. 76b). In the Amazon Basin it is highly polymorphic and its pattern may include a red base to the forewing and red radiating lines on the hindwing. There is also great diversity in the expression of the red patch, which may be entire or broken into spots, broad or narrow, red or yellow or a combination of the two (Seitz, 1913, pis. 75, 76). Towards the extremities of its mainland range the degree of polymorphism declines and geographical localities have characteristic forms. It is impossible to treat museum data quantita- tively, so without personal experience of each locality it is not possible to state reliably which are dominant morphs, but museum material probably indicates the number of patterns that are present. On the western slopes of the Andes the form known as H. cythera is conspecific with melpomene and grades round the tips of the Andean spurs in Colombia through such types as modesta and vulcanus. H. xenoclea is also conspecific with melpomene. The breeding ex- periments upon which these statements are based will be the subject of a later paper. Heliconius erato (Linnaeus 1758) (Text-figs. 16, 21, 31, 53, 74, 80, 103, 119, 140, 152, 153; Map 15; PI. I, Fig. 10 The remarkable relationship between H. mel- pomene and H. erato has aroused the interest of biologists for many years and is currently a prin- cipal topic of investigation by workers both in the Americas and in Europe. The two species, though systematically and biologically quite dis- tinct, show a similarity to each other both in color and pattern which follows their profound geographical and polymorphic variation (Seitz, 1913, pi. 78). Grossly their range appears to be identical, and they frequently fly together, though melpomene tends to prefer the interior of the forest and erato the margins. The very di- verse appearance of some of the forms, as with melpomene, led earlier taxonomists to erect many more species than should in fact be the case and there is now no doubt that forms like cyrbia, venus and microclea are all conspecific with erato. The breeding evidence for this will be published later. Heliconius sara (Fabricius 1793) (Text-figs. 18, 32, 54, 75, 102, 120, 153; Map 16; PI. I, Fig. 12) This black, blue and yellow butterfly (Seitz, 1913, pi. 77f) is fairly constant over its range though some specimens, which in some locali- ties form the predominant or only form, have the posterior margins of the hindwings white. It is a forest butterfly so the lack of records from the llanos of Venezuela and the savannas of eastern Brazil may be correct. Heliconius ricini (Linnaeus 1705) (Text-figs. 17, 33, 55, 76, 121, 153; Map 17; PI. I, Fig. 11) This black, yellow and. red butterfly (Seitz, 1913, pi. 79d) is very constant over its range, and is apparently restricted broadly to the coastal strip of northeastern South America. 96 Zoologica : New York Zoological Society [48: 8 Map 2. Dryadula phaetusa. 1963] Emsley: Morphological Study of Imagine Heliconiinae 97 Map 3. Agraulis vanillae. 98 Zoologica: New York Zoological Society [48: 8 Map 5. Dione moneta. Map 6. Podotricha euchroia. 1963] Emsley: Morphological Study of Imagine Heliconiinae 99 Map 9. Dryas iulia. 100 Zoological New York Zoological Society [48: 8 Map 11. Heliconius isabella. Map 12. Heliconius numata. Map 13. Heliconius doris. 102 Zoologica: New York Zoological Society [48: 8 Map 15. Heliconius melpomene and erato. 1963] Emsley: Morphological Study of Imagine Heliconiinae 103 Map 16. Heliconius sara. Map 17. Heliconius ricini. 104 Zoologica: New York Zoological Society [48: 8 III. Field Key to the Adults of Trinidadian Heliconiinae 1. Humeral vein of hindwing recurrent and unbranched (Key-fig. A1) Heliconiinae Humeral vein of hindwing otherwise Other Groups 2. Discal cell of hindwing open (Key-fig. A2) Discal cell of hindwing closed (Key-fig. B1) Heliconius 3. Green ground color with black markings Philaethria dido Orange ground color with black markings 4. Underside with pearly-silver spots Underside without pearly-silver spots 5. Androconia of males absent on hindwing veins; distal margin of forewings smooth; dark band on posterior border of hindwing spotted with ground color Agraulis vanillae Androconia of males present on five veins of the hindwing (Ml, M2, M3, Cula & Culb) (Key-fig. C); distal margins of forewings scalloped; dark band on posterior border of hindwing complete, unspotted Dione juno 6. Androconia of males absent on hindwing; upper and lower surface of hindwing traversed by median dark bar; wings broad Dryadula phaetusa Androconia of males present on two anterior veins of hindwing, (Sc + R1 and Rs), (Key -fig. D); hindwing with dark border only, wings narrow. .Dry as iulia 7. Ground color predominantly black Ground color predominantly orange or orange and yellow 8. Forewing with single red patch Forewing with two yellow patches or bars 9. Base of underside of hindwing with 3 red spots (Key-fig. E) H. melpomene Base of underside of hindwing with 4 red spots (Key-fig. F) H. erato 10. Base of upper side of forewing with blue sheen Base of upper side of forewing without blue sheen 11. On the underside of the hindwing a semicircular red streak interrupted by the bases of the hindwing veins, not extending towards the centre of the wing (Key-fig. G) H. wallacei On the underside of the hindwing a semicircle of red spots, which curve towards the centre of the wing (Key-fig. H) H. sara 12. Anterior half of hindwing red, with a boundary parallel with posterior margin H. ricini Base of hindwing red, blue or green breaking up postero-distally into radiating streaks H. doris 13. Dorsal ground color orange; wings dorsally edged with black, forewings crossed with two narrow black bars only. Similar to Dryas in appearance but smaller, wing span less than 6 cm when spread H. alipliera Dorsal ground color orange and yellow with black spots, some coalesced; dorsal and ventral pattern similar 14. Underside of forewing with a pair of discrete round dark spots about the middle of the wing; the three anterior white spots on the distal margin of the underside of the hindwing approximately equal in size; and which if expressed on the dorsal surface are not yellow H. isabella Underside of forewing, though with dark markings, without a conspicuous pair of round dark spots; the two anterior white spots on the anterior margin of the underside of the hindwing conspicuously larger than the succeeding ones and one or more are expressed on the dorsal surface as a yellow spot H. numata 2 3 7 4 8 13 9 10 11 12 14 In Trinidad the vernacular names for the Heliconiinae are: Silver Spotted Flambeau— Dione juno and Agraulis vanillae; Flambeau— Dryas iulia; Caroni Flambeau —Dryadula phae- tusa; Small Flambeau— Heliconius aliphera; Grecian —H. wallacei, H. doris, H. sara and H. ricini; Postman—//, erato and H. melpomene; Tiger —H. isabella and H. numata. */~i \D 1963] Emsley: Morphological Study of Imagine Heliconiinae 105 IV. Morphology Methods of Morphological Study Unless otherwise stated, the drawings and conclusions are the result of the study of at least fifteen examples of each structure, from indi- viduals taken from diverse geographical locali- ties. All the locally available material was killed, examined, and drawn in alcohol, but in the case of some of the exotic species reliance had to be placed on dry pinned museum specimens. Semi- permanent preparations were mounted in poly- vinyl alcohol and permanent preparations in clear mount or CMC. Where necessary, material was macerated in potassium hydroxide prior to detailed examination, for which a binocular dis- secting microscope with magnifications up to XlOO and a spot lamp was found satisfactory for all but the smallest structures. A monocular with oil immersion objectives was used for mi- nute structures, such as androconia. For accuracy of proportion the drawings were made with an eye-piece grid and squared paper. Pupal trachea- tion was obtained from living material, three- quarters through development, dissected under glycerine. De-scaling was found to be most easy in water to which detergent had been added. The examination of the copulatory mechanism was accomplished by the killing of copulating pairs with the electrocuting technique described by Emsley (1958). The object of a paper of this kind is the dis- covery of features common to distinct species which will unite them at higher level, not their separation into smaller groups, hence biometry has little pertinence. In principle, qualitative rather than quantitative characters have been sought. External Anatomy Head (Text-figs. 1-20) Head Capsule: The head capsule of Dryas, when compared with the heads of other genera, revealed no structures of taxonomic value. From the drawings by Ehrlich & Ehrlich (1962) it appears that the head capsule musculature char- acters are similar in Dryas iulia and Heliconius charitonius, and these two differ from Agraulis vanillae only in the degree of development of two muscles. Though these are the only members of the Heliconiinae discussed in that paper, no other described members of the Nymphalidae are as similar. Mouthparts: In all the species studied, each galea has a row of erect ovoid tubercles on the anterior surface of the distal fifteenth of its length. Each tubercle has a small terminal papilla (Text-fig. 1). Taylor (1957) showed that the [48: 8 106 Zoologica: New York Zoological Society I; Text-fig. 1. Papillate tubercle of proboscis of Dry as iulia. Text-fig. 2. Left view of left maxillary palp of Dryas iulia. proboscis of Lepidoptera has little systematic value below family level, a view supported here, for no differences could be detected either be- tween or within genera. The palps are held erect, closely applied to the sides of the base of the proboscis, but the statement by Doubleday & Westwood (1846) that their origins are widely separate cannot be confirmed. In both sexes of all genera the palps are three- jointed and densely clothed posteriorly and lat- erally with elongate scales and anteriorly with erect hairs. Though no special structures of sys- tematic value were observed, the degree of hairi- ness is least in Philaethria, Dryadula and Dryas (Text-fig. 2) and increases in density through Heliconius, Agraulis and Dione to Podotricha. Antennae: (Text-figs. 3-20). The antennae of all species differ either in the shape of the club or in relative length, but no special structures were noticed and neither the distribution of the investment of the scales nor the shape appear to have much taxonomic value. This general con- clusion was reached by Bodine (1896) and sup- ported by Michener (1942a). Philaethria (4), Agraulis (5), Dione (9, 10, 11) and Podotricha (7, 8) have a greater development of the club than Dryas (6), Dryadula (3) and Heliconius (12-20). Thorax An examination of the thorax and axillary wing sclerites revealed no differences of value either within or among genera. The prothoracic legs (Text-figs. 21-41) are sexually dimorphic. In males the tarsus consists of only one sclerite, bears no evidence of a pre- tarsus, and is fused immovably to the tibia (Text- fig. 2 1 ). As noticed by Godman & Salvin (1901), the proportionate lengths of the leg segments of some species are specifically characteristic, though these do not aid the understanding of specific relationships. In females the reduction of the forelegs is principally due to compaction of the tarsi (Text- fig. 22) , which are severely limited in their move- ment and are normally held closely applied to the ventral surface of the meso-thorax. Com- parison of the foretarsi shows that the least modi- fied and presumably the most primitive are Philaethria (23), Dryadula (24), Dryas (25), Podotricha (26), Heliconius numata (27), H. wallacei (28), H. doris (29), H. melpomene (30), H. erato (31) and H. sara (32), which are all basically similar, with the proximal tarsal segment of nearly normal length and with tarsal segments 2, 3, 4 and 5 reduced almost to annuli. The most distal segment bears a terminal spine which presumably represents the degenerate pre- tarsus. Within Dione, D. juno (34, 35) has the terminal spine reduced to a prominence, D. gly- cera (36) has the prominence finer and set in a shallow vertical groove and D. moneta (37) has the prominence absent and the groove deep- er, a condition almost identical with that of Agraulis vanillae (38, 39). Heliconius isabella (40) and H. aliphera (41) have only four tarsal segments, and the latter species also lacks the terminal spine. The way in which the fifth seg- ment has been lost may be indicated by H. ricini (33), which exhibits an intermediate state with incomplete separation of tarsal segments one and two, though at this stage the stout ventral spines are still present, of which there are nor- mally a pair on each segment with the exception of the most distal. In all the female foretarsi examined there is a special association between the ventral spines and the specialized hairs which arise from cir- cular areas of differentiated cuticle. The view that the female forelegs are functionless (Imms, 1957) should be qualified, for though unsuited to assist locomotion, the specialized arrangement of the hairs on the tarsi does not suggest a func- tionless organ. The investment of stout hairs and weak spines on the lateral and dorsal sur- faces of the tarsi may be subject to specific ar- rangement, but it is very difficult to descale the tarsi without removing at least some of the spines as well, and once removed their origins are diffi- cult to detect. Careful examination of Philae- thria revealed no spinous structures on the proxi- mal tarsal segment. Meso- and Metathoracic Legs (Text-figs. 42, 43 ) : The structure of the legs is orthodox, simi- 1963] Emsley: Morphological Study of Imagine Heliconiinae 107 3 4 5 6 1 12 14 <5 15 IO i cm 20 Text-figs. 3-20. Left view of left antennae of Heliconiinae. Dryadula phaetusa, 3; Philaethria dido, 4; Agraulis vanillae, 5; Dryas iulia, 6; Podotricha telesiphe, 7; P. euchroia, 8; Dione moneta, 9; D. glycera, 10; D. juno, 11; Heliconius wallacei, 12; H. doris, 13; H. melpomene, 14; H. numata, 15; H. erato, 16; H. ricini, 17; H. sara, 18; H. isabella, 19; H. aliphera, 20. 108 Zoologica: New York Zoological Society [48: 8 p mm Text-fig. 21. Left view of left male prothoracic leg of Heliconius erato. Text-fig. 22. Left view of left female prothoracic leg of Dry as iulia. lar in both sexes, and shows no features of spe- cial interest except that Dione and Podotricha are alone in having hairs on the femora. In Trini- dad Heliconiinae frequently have the translators of Asclepias (milkweed) attached to the spines of the meso- and metathoracic tibiae, and are presumably important pollinators of this wild herb. The pretarsi (Text-figs. 44-61) are similar on the meso-and metathoracic legs of both sexes. All genera except Dione and Agraulis have basically similar pretarsi with a pair of long curved claws, between which arise a large arolium and a pair of bifid paronychia. The dorsal and ventral proc- esses of the paronychia (Text-fig. 45, Dpp and Vpp) exhibit variation in relative length, though the dorsal processes are consistently the more strongly sclerotized and are closely associated with the claws. In Philaethria (44), Dryadula (45 ),Dryas (46) , Podotricha (47,48) and some species of Heliconius (49-52) the dorsal and ven- tral paronychial processes are nearly equal in length, whereas in the other species of Heliconius (53-55) they are widely different in length and in Dione (58-60) and Agraulis vanillae (61) the paronychia are vestigeal. In H. numata (49), H. wallacei (50), H. mel- pomene (51) and if. dor is (52) the ventral paro- nychial processes are more than half as long as the dorsal processes but in H. erato (53) , H. sara (54) and H. ricini (55) the ventral processes are less than a third as long as the dorsal ones. The paronychia of H. isabella ( 56) and H. aliph- era (57) have much broader tips than any other species studied but are otherwise similar to other Heliconius, most particularly the group to which H. numata belongs. Dione juno (58) and Agrau- lis vanillae (61) have a pair of similar, long, medi- ally straight claws but lack the arolium and have poorly developed paronychial lobes. That the lobes are bifid in origin is shown more clearly in D. glycera (59) and D. moneta (60). Pretarsal differentiation can be expected to be closely adapted to specific habits and are probably among the less useful taxonomic characters for establishing interrelationships, but from field ob- servations no habits common to Agraulis and Dione, which differ from the remainder of the Heliconiinae, have been observed. The wings (Text-figs. 62-80) of Heliconiinae are recognised by their high aspect ratio, though this is pronounced only in Podotricha (65, 66), Dryas (67) and Heliconius (70-78). Genera like Dryadula (69) are nearer the normal nympha- line proportions. The wings may have rounded distal margins as in Dryadula (69), Agraulis (68) and most species of Heliconius (70-78) or they may be scalloped as in Dione (63-64) and some other species of Heliconius not figured. The substantial emargination of the forewing of Podotricha (65-66) in the region of M3 and Cula may be seen developed to a lesser extent in Dione (63-64) and is just perceptible in Phil- aethria (62), Dryas (67) and Agraulis (68). The venation (Text-figs. 62-80) of the Heli- coniinae is unique for the exhibition on the hind- wing of an unforked recurrent humeral branch of Sc. The subfamily may be divided into two groups, for though in all genera the discal cell of the forewing is closed by the crossveins M2- M3 and M3-Cula (Text-figs. 67, 74), only in Heliconius is the crossvein M2-M3 present on the hindwing too (Text-fig. 74). The absence of this crossvein in the other genera leaves the discal cell open (Text-fig. 67). The extent to which the vestiges of the stems of R4 + R5 and M are visible in the adult forewing is subject to considerable variation in each species, but in all cases only the base of Cu2 can be identified, and on the hindwing all trace of the base of M and Cu2 has been lost, except Cu2 in some speci- mens of H. numata (71). The homologies of the veins labelled in the drawings of Dryas iulia (67) and Heliconius erato (74) can be confirmed by reference to the pupal tracheations which are shown in Text-figs. 79 and 80. In the past, taxo- nomic use has been made of the point of origin of R1 of the forewing relative to the antero- distal angle of the discal cell, but it is not a good character as it is subject to considerable variation and even the sexual dimorphism of Agraulis cited by Michener (1942a) cannot be substan- tiated. This variation is not surprising, for the pupal tracheation shows a complex association 1963] Emsley: Morphological Study of Imagine Heliconiinae 109 Text-figs. 23-33. Right view of right prothoracic leg of female Heliconiinae. Philaethria dido, 23; Dry- adula phaetusa, 24; Dryas iulia, 25; Podotricha telesiphe, 26; Heliconius numata, 27; H. wallacei, 28; H. doris, 29; H. melpomene, 30; H. erato, 31; H. sara, 32; H. ricini, 33. of trachea in this region (Text-figs. 79 and 80) and the critical point is where the tracheae which precede R2 + 3 and R4 + 5 first meet. Apart from the separation of Heliconius by the closure of the discal cell on the hindwing, the only other venational feature of systematic interest is the similarity of the unusual course of Sc + R1 and M2 in Dione glycera and D. moneta which is associated with the pattern of silver spots on the ventral surface; D. juno is almost unmodified in this respect. The androconia (Text-figs. 81-92) of nearly 110 Zoologica: New York Zoological Society [48: 8 all the genera can be distinguished by then- shape, though their basic structure seems uni- form. The odor-disseminating region is probably confined to the distal zone where the scales are finely divided and highly refractive. Dryadula (88), Dryas (hindwing) (89), and Heliconius (90-92) are similar in having squat rectangular androconia, and those of isabella (92) and H. aliphera are almost square. The androconia of Agraulis vanillae (81), Dione moneta (82), D. glycera (83), D. juno (84), Dryas iulia (forewing) (85), Podotricha (86), Philaethria dido (87), Dryadula phaetusa (88) and Heliconius (90-92) form a series which decreases regularly in length. The andro- conia of some Heliconiinae were studied and figured by Muller (1877a; 1877b). Dryas is es- pecially interesting as the forewing androconia are elongate and similar to those of Philaethria, Podotricha and Dione juno, whereas the andro- conia of the hindwing are short and similar to those of Heliconius and have a similar distribu- tion. The distribution of the androconia (Text-figs. 62-78) on the wings of male Heliconiinae is an important systematic character and will be de- scribed first under each genus and then as a whole. In Philaethria dido (62), all the distal veins of the forewings except C, Sc, Rl, and R2, and Text-figs. 34-41. Right view of right prothoracic leg of female Heliconiinae. Dione juno, 34, 35; D. glycera, 36; D. moneta, 37; Agraulis vanillae, 38, 39; Heliconius isabella, 40; H. aliphera, 41. Text-fig. 42. Right view of right mesothoracic leg of Dryas iulia. Text-fig. 43. Right view of right metathoracic leg of Dryas iulia. 1963] Emsley: Morphological Study of Imagine Heliconiinae 111 «- 9 0-5 mm Text-figs. 44-61. Heliconiine mesothoracic pretarsi. Philaethria dido, 44; Dryadula phaetusa, 45; Dryas iulia, 46; Poclotricha telesiphe, 47; P. euchroia, 48; Heli- conius numata, 49; H. wallacei, 50; H. melpomene, 51; H. doris, 52; H. erato, 53; H. sara, 54; II. ricini, 55; H. isabella, 56; H. aliphera, 57; Dione juno, 58; D. glycera, distal lateral margin of paronychium only, not to scale, 59; D. moneta, ditto, 60; Agraulis vanillae, 61. Ventral views shown. Legend: Dpp— Dorsal paronychial process. Vpp— Ventral paronychial process. Cl— Claw. P— Pulvillus. 58 6! 112 Zoologica: New York Zoological Society [48: 8 Text-figs. 62-65. Dorsal view of right fore and hind wings of Heliconiinae. Twice natural size. Androconia are shown as solid black lines on the veins. Philaethria dido, 62; Dione juno, 63; D. glycera, 64, D. moneta similar; Podotricha euchroia, 65. 1963] Emsley: Morphological Study of Imagine Heliconiinae 113 Text-figs. 66-69. Dorsal view of right fore and hind wings of Heliconiinae. Twice natural size. Androconia are shown as solid black lines on the veins. P. telesiphe, 66; Dry as iulia, 67; Agraulis vanillae, 68; Dryadula phaetusa, 69. 114 Zoologica: New York Zoological Society [48: 8 Text-figs. 70-73. Dorsal view of right fore and hind wings of Heliconiinae. Twice natural size. Androconia are shown on the veins in black, and on the membrane stippled. Heliconius wallacei, 70; H. numata, 71; H. doris, 72; H. melpomene, 73. 1963] Emsley: Morphological Study of Imagine Heliconiinae 115 Text-figs. 74-78. Dorsal view of right fore and hind wings of Heliconiinae. Twice natural size. Androconia are shown on the veins in black, and on the membrane stippled. H. erato, 74; H. sara, 75; H. ricini, 76; H. aliphera, 77; H. isabella, 78. 116 Zoologica: New York Zoological Society [48: 8 Text-fig. 79. Pupal wing pads of Dryas iulia showing tracheae as solid lines and the adult venation dotted. Forewing on left, hindwing on right. Text-fig. 80. Pupal wing pads of Heliconius erato showing tracheae as solid lines and the adult venation dotted. Forewing on left, hindwing on right. all the distal veins of the hindwings except 1A and 2A have androconia along almost their whole length. This is contrary to the statement by Michener (1942a) that androconia are ab- sent on the wing veins. For the nomenclature of the venation see the wings of Dryas iulia (Text- fig. 67). The distribution of androconia in Dione juno (63) is similar to that of P. dido except that they are also absent on R3 of the forewings, and Sc + R1 and Rs on the hindwings. In D. glycera (64) and D. moneta, androconia are absent from hindwing Culb as well. On the forewings of Podotricha (65, 66), an- droconia are present only on veins Ml, M2, M3, Cula, Culb and 1A, and on the hindwings P. euchroia has them on wingveins Ml, M2, M3, Cula and Culb, and P. telesiphe only on veins Ml, M2, and M3. Only vein 1A of the forewing has a heavy investment of androconia; on the re- maining veins of both pairs of wings they are very sparse indeed. In Dryadula phaetusa (69), androconia occur on all the forewing veins except C, Sc, Rl, R2, R3 and R4 and are entirely absent from the hindwing. Michener (1942a) overlooked the androconia. The distribution of androconia in Agraulis vanillae (68) is similar to that of Dryadula ex- cept they are also absent from R5 of the fore- wing. There is geographic differentiation in the dis- tribution of the forewing androconia of Dryas (67), an account of which is given under the Systematic Synopsis. On the continental forms, androconia are present only upon forewing veins Cula, Culb and 1A and on hindwing veins Sc + R and Rs, but some Greater and Lesser Antillean specimens have androconia also on forewing veins Ml, M2 and M3. It is likely that the inheritance of the androconial pattern is con- trolled by a simple genetic mechanism. In addi- tion to the forewing androconia, they are present also on the two anterior hindwing veins Sc + Rl and Rs, and their arrangement in transverse rows which alternate with normal scales produces an effect very similar to that seen in Heliconius, which also has androconia on these veins. 1963] Emsley: Morphological Study of Imagine Heliconiinae 117 Text-figs. 81-92. Heiiconiine androconia: Agraulis vanillae, 81; Dione moneta, 82; D. glycera, 83; D. juno, 84; Dryas iulia forewing, 85; Podotricha euchroia, 86; Philaethria dido, 87; Dryadula phaetusa, 88; Dryas iulia, hindwing, 89; Heliconius numata, 90; H. wallacei, 91; H. isabella, 92. In most of the species of Heliconius studied for this paper, androconia are confined to veins Sc + R1 and Rs of the hindwing, on the neigh- boring membrane and on vein 1A of the fore- wing, but H. wallacei (70) and some species allied to numata, but not represented in Trinidad, have in addition androconia on forewing veins M2, M3, Cula and Culb and hindwing veins Ml, M2, M3, Cula, Culb and sometimes 1A. The androconia that can be found occasionally on the posterior margin of the forewing have probably been dislodged from the hindwing. Michener (1942a) does not describe androconia in Heliconius. The species available in Trinidad fall into five groups. (a) Those which have a dense investment of androconia on hindwing veins Sc + R1 and Rs, and over a substantial portion of the membrane around them; have some andro- conia on other hindwing veins; and on some forewing veins additional to 1 A. H. wallacei (70) is the only representative of this group from Trinidad. (b) Those with a dense investment of andro- conia only on hindwing veins Sc + R1 and Rs and on the membrane around them, and on forewing vein 1A; Heliconius numata (71), H. doris (72) and H. melpomene (73) belong to this group. (c) Those with a distribution similar to (b) but in which the investment of androconia on the membrane around Sc + R1 and Rs is more restricted and much less dense, emphasizing the contrast between vein and membrane. The androconia on 1A of the forewing are also less obvious. H. erato (74) , H. sara (75) and H. ricini (76) be- long to this group. (d) Those with androconia only on hindwing veins Sc + R1 and M and Cu. There are no androconia on the membrane. H. aliphera (77) is the only representative from Trini- dad. (e) Those with the androconia restricted en- tirely to veins Sc + R1 and Rs of the hind- Text-fig. 93. Generalized diagram of female reproductive system and female abdominal scent glands and processes. Legend: ace. gl.— accessory gland; d. sc. gl— dorsal scent gland; afod. pr.— abdominal process; eop. p.— copulatory pore; cop. d.— copulatory duct; ovd.— oviduct; ©v.— ovariole; ©v. p.— oviducal pore; sig. — signum; b. e©p.— bursa copulatrix; sp. gl.— spermatheca gland; sp. div.— spermathecal diverticulum; sp. d. — spermathecal duct. wing. H. Isabella (78) is the only Trinidad representative. Assuming that the most complete pattern, as exhibited by Philaethria (62), is primitive, then ignoring minor variations, the distribution of androconia in Dryadula (69) and Agraulis (68) can be achieved by the loss of androconia from the hindwing veins. The condition in Dione (63, 64) and Podotricha (65, 66) can be achieved by the loss of androconia on hindwing veins Sc + R1 and Rs, and that of Dry as (67) by the loss of androconia on all the hindwing veins ex- cept Sc + R1 and Rs. That the genetic constitu- tion of the Heliconiinae is compatible with the suggestion that discrete groups of veins can lose their androconia is supported by the variation demonstrated by the forewings of Dryas. Heli- conius (70-78) shows some diversity in distri- bution but they all have in common the alternate transverse rows of dense androconia on hind- wing veins Sc + R1 as in Dryas. Abdomen The female scent glands (Text-figs. 93-103) are the principal structures of interest on the pregenital abdominal segments and characterize the subfamily. They are medianly divided struc- tures which are a development of the dorsal membrane separating abdominal segments eight and nine (Text-fig. 93). The glands consist of a pair of highly infolded cuticular pouches whose lining is presumably secretory, and which are capable of eversion, apparently by hydraulic pressure. The exposed surface of the gland is highly sculptured, presumably to increase the surface area (Text-figs. 94, 95). There are at least generic differences in gland sculpture but the difficulties of preparation and accurate in- terpretation make them unreliable for systematic purposes. The females of Philaethria dido (98), Dryas iulia (99), Agraulis vanillae (97), Dione (96), Podotricha and Heliconius each have a pair of ventro-lateral processes developed from the pos- terior margin of the eighth segment which pro- ject dorsally (Text-fig. 93), and which in repose lie within the dorsal scent glands. The processes are not articulated at their base but are rigid outgrowths of the sternum, and with ventral flex- ing of the abdomen the capitate heads are with- drawn from the gland. The shape of the proc- esses and their clothing of scales show generic 0-25 mm Text-figs. 94 & 95. Detail of infolding of female dorsal abdominal glands. Dryadula phaetusa, 94; Dryas iulia, 95. 1963] Emsley: Morphological Study of Imagine Heliconiinae 119 Text-figs. 96-103. Abdominal processes of female Heliconiinae. Details of specialized scales inset to right. Dione juno, 96; Agraulis vanillae, 97; Philae- thria dido , 98; Dryas iulia, 99; Heliconius mel- pomene, 100; H. isabella, 101; H. sara, 102; H. erato, 103. features, some of which are figured by Muller (1878). In Philaethria dido (Text-fig. 98) the process is short with a spherical tip, densely clothed with scales which are entire and blad- der-like. Dryas iulia (99) has a more club- shaped process with a more sparse clothing of laterally flattened apically dentate scales. Dione juno (96), moneta, and glycera, Podotricha euchroia and telesiphe and Agraulis vanillae (97) are similar in that the processes are strong- ly capitate with a slender pedicel and the scales are excessively elongate and hair-like. The deep- ly bifid condition of A. vanillae is developed to a lesser extent in many of the scales of Dione, but the scales of Podotricha are unbranched. Heliconius (100-103) shows considerable di- versity in the shape of the processes but in all the species studied the scales are like an inverted hollow cone with deeply divided walls. Dryadula phaetusa has no processes, though the dorsal scent glands are more highly developed. The complement of scales on the capitate heads of the processes varies according to whether they are examined before or after copulation, for during copulation the appendages are withdrawn from the scent glands by the depression of the tip of the abdomen and fit into grooves on the inner face of the male genital valves; this may be an involuntary movement due to the depression of the abdomen during copulation. The male genitalia (Text-figs. 104-123) has in the past been the chief non-alary character used in papilionoidian taxonomy, though the in- terpretation to be placed on the diversity of valvular form is only recently becoming under- stood. Studies like those of Lorkovic (1956) and Turner, Clarke & Sheppard (1961) are re- jecting the lock and key concept of the function of the valves. Examination of specimens electro- cuted in the act of copulation, using the tech- nique described by Emsley ( 1958) , shows clear- ly that it is the uncus and gnathos (Text-fig. 105) that are the principal grasping organs together with the inflatable tip of the aedeagus (Text-fig. 104). The inflatable pouches at the base of the valves are in intimate contact with the female but seem to have a function other than that of Text-fig. 104. Left view of aedeagus of Dryadula phaetusa to show obliquely truncate tip. 120 Zoologica: New York Zoological Society [48: 8 Text-fig. 105. Diagram to illustrate mechanism of copulation. Legend. AedL— aedeagus; Cop. pore— copulatory pore; g no.— gnathos; one.— uncus. prehension. The distal portions of the valves of the male have little or no contact with the female and are independently free to exploit genetic variability, hence the development of the bizarre extremities exhibited by Dryadula (106) and Philaethria (107). That this is the method of copulation could have been deduced from the manipulation of living and preserved material, for the uncus is flattened laterally for insertion into the female egg pore, and the gnathos is flattened dorso-ventrally to grasp the roof of the copulatory pore, which is locally heavily sclerotized. The aedeagus (104) is obliquely truncate and fits closely against the lower sur- face of the gnathos, which acts as a guide for its introduction into the copulatory pore (105). The aedeagus is inserted approximately three- quarters of the length of the ductus bursa, the remaining distance being accomplished by ever- sion of the lining of the ejaculatory duct, which expands within the bursa copulatrix and assists in preventing accidental withdrawal. Dryas iulia is peculiar in that it has at the dorsal tip of the aedeagus a group of approximately ten strong spines whose function is unknown. The male genital valves (Text-figs. 106-123). Text-figs. 106-114. Inner aspect of left genital valves of male Heliconiinae. Dryadula phaetusa, 106; Philaethria dido, 107; Agraulis vanillae, 108; Dione juno, 109; D. glycera, 110; D. moneta, 111; Podo- tricha euchroia, 112; P. telesiphe, 113; Dryas iulia, 114. 1963] Emsley: Morphological Study of Imagine Heliconiinae 121 From a study of the valves, the erection by Michener of numerous genera seems justified, particularly in view of the similarities within genera like Dione (109-111) and Podotricha (112-113). Though in general the valves do not suggest intergeneric relationships, there is a striking similarity between the Heliconius type of valve (e.g., 119-121) and that of Dryas iulia (114) , and they are of considerable value in erecting species groups. Within Heliconius three groups can be recognized. Firstly: H. wallacei (115) , H. numata (116), H. doris (117) and H. melpomene (118), are united by the elon- gate and spinose development of the dorsal process of the valve which makes it considerably longer than the conical and smooth ventral proc- ess. Secondly: H. erato (119), H. sara (120), and H. ricini (121) have the dorsal process re- duced and smooth so the rounded ventral proc- ess is the more prominent, though H. erato ap- proaches the condition seen in melpomene. Thirdly: H. aliphera (122) and H. isabella (123) have both the upper and lower processes approximately equally developed but the lower process is, or has a tendency to be, bifid. These two species each have a spinose region on the inner surface of the dorsal process, a feature not developed in the H. erato, H. sara, H. ricini group, but which is seen in some other species of Heliconius, like H. wallacei, and in Dione. No characters of systematic value were de- tected on the other components of the male geni- talia. The female genitalia (Text-figs. 93, 124-152) of ditrysic lepidoptera include internal ectoder- mal structures which are lined with cuticle. The relationships of the component parts are illus- trated in Text-fig. 93. The important features are the bursa copulatrix (b. cop), into which the sperm are deposited as a spermatophore during copulation; the spermatheca (sp.d.), to which the sperm migrate after the rupture of the sper- matophore; and a pair of accessory glands (acc. gl.) which are responsible for the secretion of the adhesive which secures the egg to the sub- strate. The bursa copulatrix has a shape which is subject to considerable variation in each species due to its state at the time of the capture of Text-figs. 115-123. Inner aspect of left genital valves of male Heliconiinae. Heliconius wallacei, 115; H. numata, 116; H. doris, 117; H. melpomene, 118; H. erato, 119; H. sara, 120; H. ricini, 121; H. aliphera, 122; H. isabella, 123. 122 Zoologica: New York Zoological Society [48: 8 Text-figs. 124-126, 130-132, 137-139. Right view of bursa copulatrices of Heliconiinae. The right signum is shaded. Philaethria dido, 124; Dryadula phaetusa, 125; Dryas iulia, 126; Podotricha euchroia, 130; P. telesiphe, 131; Agmulis vanillae, 132; Heliconius melpomene, 137; H. wallacei, 138; H. doris, 139. the insect (i.e., pre-copulation, post-copulation, before or after the rupture of the spermato- phore) and due to methods of preservation and subsequent treatment. For these reasons it was found that the shape, though potentially of value, if given homogenous material, is in practice un- satisfactory. In all species, other than some Heli- conius, there is a strongly chitinized signum (sig.) on each side of the bursa copulatrix, whose function is assumed to be the rupture of the 1963] Emsley: Morphological Study of Imagine Heliconiinae 123 Text-figs. 127-129, 133-136, 140 & 141. Dione glycera, 127; D. moneta, 128; D. juno, 129; Heliconius aliphera, 133; left signum as seen from the right side, 134; H. Isabella, 135; H. numata, 136; H. erato, 140, H. sara and H. ricini similar; detail of interior of right signum of P. euchroia, 141. spermatophore with the subsequent release of the sperm. The signa consist of a number of sharp chitinous spines (Text-fig. 141) which project into the lumen of the bursa copulatrix. The shape of the signum is reasonably constant within species but considerable and valuable dif- ferences are apparent among species. Its value in generic classification is small, for the differ- ences within Heliconius are considerably greater than those between genera like Philaethria, Dry- 124 Zoologica: New York Zoological Society [48: 8 adula and Dry as (Text-figs. 124-126) , yet within Dione and Podotricha the signa of the constitu- ent species are very similar (127-131). Agraulis vanillae (132) is unique in that it has a lateral vertical constriction of the bursa copulatrix which passes through the signa, and the chitinous teeth are coarser than those of any other species examined. Within Heliconius few conclusions can be drawn without a full survey of the genus but the signa of H. isabella (135) and H. ali- phera (133, 134) are more like Dryas iulia (126) or Philaethria dido (124) than any other member of Heliconius studied. H. aliphera is unusual in that the signa are asymmetrical; on the right side it resembles P. dido and on the left Dryas iulia. The signa of H. wallacei (138) and H. melpomene (137) are alike and similar to H. numata (136) , which is larger, and H. doris (139) which is smaller. H. erato (140), H. sara and H. ricini have no signa at all. The spermatheca (Text-figs. 142-152) is prone to damage both during preservation and in dis- section but it gives some characters which per- sist even in ill-treated material. A diverticulum is attached to the spermatheca in Philaethria (142), and Podotricha (143) by a very narrow duct, which is slightly wider in Dryas (144) and wider still in Dry adula ( 145) , H. isabella ( 146) , H. aliphera (147) and Dione (148-150). In Agraulis vanillae (151) and the other species of Heliconius studied, the diverticulum is attached directly without the differentation of a duct. The bicornuate accessory glands (Text-fig. 93) are lined with chitin and are clearly recog- nizable in dried material. They appear uniform throughout the group, though due to different preservation techniques and differences in their physiological state at the time of capture, their appearance is variable. Internals The internal anatomy of the genera available in Trinidad was examined but no features of sys- tematic interest were recognized. The nervous system and gut are typically nymphalid. The male reproductive system exhibits a median globular testes from which two vasa deferentia emerge like the aortae of a mammalian heart, showing the fused testes have been rotated through 180°. The one specimen of Philaethria dido that was available for study did not show this rotation and one Heliconius numata out of the six examined had two separate testes. In all the species examined, a pair of accessory glands open into the vasa deferentia just proximal to the point where they join each other. The ecto- dermal internal female reproductive organs have been described earlier under female genitalia. Each of the two ovaries is composed of four ovarioles. V. Discussion Over eighty-five years ago Muller (1877a) suggested that the genera Colaenis (which in- cluded Philaethria), Dione (which included Agraulis and Podotricha ) and Heliconius (which included Eueides) should be considered a tax- onomic unit. He united these genera on many characters, some morphological and some bio- logical involving eggs, larvae, pupae, and adults. Subsequent attempts that have been made to divide the group have been based primarily on the presence or absence of the hindwing cross- vein M2-M3 which separates off Heliconius from the other genera. This division does not seem any more valid than to isolate those genera in which there are androconia on the hindwing veins Sc + R1 and Rs, which would differentiate Philae- thria, Dryas and Heliconius from the rest. Sim- ilarly, when characters other than venation and color-pattern are considered, no case can be made for species groupings such as those of Stichel (1938) who placed Dryas iulia and Dry- adula phaetusa (as species of Colaenis) in the section Apotorneuthes, and contrasted them with Podotricha euchroia and P. telesiphe (also as species of Colaenis) in the section Apotomemati. However, his separation of Dione juno as the section Goniosimi away from the section Stron- gylotypici, which contained Agraulis vanillae, Dione moneta and D. glycera (all as species of Dione), is more realistic. The recognition of seven distinct genera by Michener (1942a) is reasonable and acceptable, through several ge- neric groupings can be identified, but for which no new names are proposed. On consideration of the characters examined in this paper, the peculiar features the adults have in common are, the recurrent Sc of the hindwing, the dorsal abdominal glands and ven- tral processes of females, and the wing vein androconia of males. These seem to be diagnos- tic group characters. Other systematic charac- ters of value include venation, the structure and distribution of androconia, the pretarsi, the fe- male foretarsi, the signa of the bursa copulatrix, the spermatheca and, to a more limited extent, the male genitalia. In the following discussion it will be shown that there are three generic groupings within the subfamily. Reference should be made to the family-tree (Text-fig. 153). Sub-group ( 1 ) : Philaethria, which has a unique color-pattern, has a wider distribution of wing-vein androconia than any other member of the Heliconiinae. The pretarsi and female foretarsi are typically nymphalid and apparently 1963] Emsley: Morphological Study of Imagine Heliconiinae 125 Text-figs. 142-152. Heliconiine spermathecae, with the proximal portion of the spermathecal duct and the distal spermathecal gland removed; d is the spermathecal diverticulum. Philaethria dido, 142; Podo- tricha euchroia, 143; Dryas iulia, 144; Dryadula phaetusa, 145; Heliconius Isabella, 146; Ii. aliphera, 147; Dione juno, 148; D. moneta, 149; D. glycera, 150; Agraulis vanillae, 151; Heliconius erato, 152. unspecialized. The palps are the least hairy. The androconia are of the most common shape. The signa of the bursa copulatrix has both lateral and vertical limbs well developed, and is of a a boomerang shape from which all the other shapes seen in the subfamily could have been derived by a differential reduction. The male genitalia show a bizarre development of the distal extremities but this is of little value in establishing inter-generic relationships, for, as has been shown, the valves, or claspers, play no part in the prehension of the female and do not form part of a lock and key mechanism to ensure specific isolation. They have become free to ex- ploit genetic variability to the full, for, as far as can be seen, their characters are non-adaptive. Philaethria should be regarded as the most con- servative member of the Heliconiinae, for it ex- 126 Zoologica: New York Zoological Society [48: 8 Text-fig. 153. Family tree. hibits several subfamily characters in their most generalized form and has no relevant specializa- tions. Sub-group (2): The Dryadula - Agraulis- Dione-Podotricha group. Apart from the posses- sion of androconia on at least six forewing veins there is no single character which unites these genera, though they may be linked in successive pairs and are more closely related to each other than to any other members of the subfamily. Dryadula and Agraulis share a similarity of forewing shape though the hindwing of Dryadula is more rounded distally. They have a similar distribution of forewing androconia and both lack androconia on the hindwings. That these two are not very closely related is indicated by the differences in the shape of the androconia and signa, the reduction of the pretarsi and terminal spines of the female foretarsi in Agrau- lis and the absence of female abdominal proc- esses in Dryadula. The male genitalia also show considerable differences, but these need not be stressed. Agraulis and Dione are linked by at least the following characters: the similar pattern of silver spots on the underside of the wings and the principal elements of the upper surface wing pattern, a likeness which is reinforced by the form A. v. lucinia, the reduction of the meso- and metathoracic pretarsi, the reduced terminalia of the female foretarsi, the strongly capitate female abdominal processes and their hair-like bifid scales, the high degree of hairiness on the palps, the broad duct to the spermatheca diverticulum, and the elongate character of the androconia. There are minor differences in wing shape in that Dione has the distal margin of the forewing more strongly emarginate and there is slight scalloping of the posterior margin of the hind- wing. The principal difference is in the distribu- tion of androconia, for Dione has them on some hindwing veins, but not on Sc+Rl or Rs, where- as Agraulis has no hindwing androconia at all. The difference in the signa is due principally to the median constriction that is peculiar to Agrau- lis. The male genitalia are distinct but this is not considered of great significance. Within Dione, in addition to differences in male genitalia and signa of an order expected between distinct species, there is a considerable difference in the shape of the androconia, for D. moneta has androconia which resemble those of Agraulis, D. juno has androconia of more normal shape, and D. glycera is intermediate. This sequence is seen again in the structure of the terminal joint of the female foretarsi. How- ever the characters of the male genitalia, signa, spermatheca and androconial distribution com- bine the three species of Dione more closely together than any one of them can be joined with Agraulis, though D. moneta seems more close to Agraulis than either of the other species, a relationship suggested by Stichel though with- out evidence. Dione and Podotricha have many common characters which include wingshape, though the emargination of the forewing noticed in Dione is even more highly developed in Podotricha, and the posterior margin of the hindwing is more heavily scalloped. The distribution of the an- 1963] Emsley: Morphological Study of Imagine Heliconiinae 127 droconia is similar, though the over-all density is less in Podotricha, and the structure of the androconia is similar when D. juno is used for comparison. The pretarsi, female foretarsi, fe- male abdominal processes and their scales are similar, though the signa of Podotricha is re- duced in size. The male genital valves of the two species of Podotricha can be distinguished from each other and are substantially different from those of Dione. The relationships between Agraulis, Dione and Podotricha are complex. On the small amount of evidence presented it seems likely that the mutual ancestor, already distinct from Proto-Dryadula, differentiated into two species, one of whose distinguishing characters was a ten- dency to have elongate androconia, and a reduc- tion of the terminalia of the female foretarsi. Subsequently this latter group differentiated into an upland species which changed very little and still possesses the principal Dione characters, as D. moneta, and a principally lowland species which diverged markedly, losing the hindwing androconia and becoming Agraulis vanillae. A case could be made for returning Agraulis to the genus Dione but insufficient weight can be placed on the present evidence to warrant such a major taxonomic change. D. glycera is prob- ably a conservative member of the D. moneta line which has retained some of the features possessed by Proto-moneta during its differen- tiation from Proto-juno. In addition to the an- droconial and female prothoracic leg characters already mentioned, D. glycera and D. moneta share the similar peculiar path of the hindwing veins Sc+Rl and M2. The two species of Podo- tricha are very close and are probably an offshoot of the juno side of the Dione bifurcation. Sub-group (3): Dry as and Heliconius are united by the shape of the wings and the posses- sion of similarlv-arranged androconia on the hindwine veins Sc+Rl and Rs. No other genus except Philaethria has androconia on these veins. The lack of the crossvein M2-M3 in Dryas has prevented previous taxonomists from consider- ing these two genera closely related, but not only is the distribution of androconia similar, but the structure of the hindwing androconia is similar, as are the pretarsi, female foretarsi, signa and female abdominal processes. Heliconius can be divided into two groups, one of which can be subdivided. In the material studied, the Trinidad members of the old genus Eueides, that is, Heliconius aliphera and H. Isabella , can be separated off from the rest on a number of characters. Their signa are alike and of the boomerang shape seen in Dryas and Philaethria, in particular the signa of H. aliphera is asymmetrical and resembles Philaethria on one side and Dryas on the other. Also the andro- conia are similar in structure to those of Dryas though somewhat more squat, and as in Dryas occur only on the veins of the hindwing. In all the other species of Heliconius studied they occur on the membrane around Sc+Rl and Rs as well. H. aliphera has some androconia on branches of hindwing M and Cu as well as Sc+Rl and Rs, a condition which resembles Philaethria though H. Isabella has them re- stricted to Sc+Rl and Rs. Moreover, the duct to the spermatheca is unlike that of any other species of Heliconius and like that of Dryas and Philaethria, in that it is narrow and not broad. Also the shape of the female abdominal processes is more pedicelate than the advanced species of Heliconius, a feature seen elsewhere in Agraulis, Dione and Podotricha. Against this evidence one must recognize in both H. aliphera and H. isabella the reduction of the female foretarsi and the peculiar shape of the parony- chia which, though they resemble the generalized pattern of Philaethria and Dryas, have spatulate tips. In view of the gross similarities among H. aliphera and H. isabella and other genera like Philaethria and Dryas, it is reasonable to assume that these two species are among the more prim- itive in Heliconius, but are not on the direct line of descent of the more highly evolved species. Hitherto these members of the old genus Eueides have been placed last in taxonomic lists, suggesting that they are among the most ad- vanced, but in future, if confirmed by a more thorough study of Heliconius, they should be placed near the beginning. Within the remainder of Heliconius there is a clear division separating H. wallacei, H. doris, H. numata and H. melpomene from H. erato, H. sara and H. ricini. The first group have the following characters in common which contrast with the second group. (i) Dense androconia on the membrane around Sc + Rl and Rs of the hindwing. H. wallacei and some species (?) of numata that do not occur in Trinidad have andro- conia on branches of M and Cu on both fore- and hindwings, and in view of the possession of androconia in these positions by other genera this is probably a primitive feature. In H. erato, H. sara and H. ricini the androconia are only sparsely distributed over the membrane around Sc + Rl and Rs. (ii) The possession of a signa on the bursa copulatrix. Though these vary specifically in shape, those of H. numata and H. mel- 128 Zoological: New York Zoological Society [48: 8: 1963] pomene are very much alike and differ from both H. wallacei and H. doris. There are no signa in H. erato, H. sara and H. ricini, but it is possible that the signa have been lost independently. (iii) The male genitalia have a spinose orna- mentation of the elongate dorsal process of the valve, in contrast to the abbreviated rounded shape of H. sara and H. ricini, though H. erato resembles H. melpomene in that it is slightly spinose apically. (iv) The pretarsi have the ventral processes of the paronychia at least half as long as the dorsal processes. In H. erato, H. sara and H. ricini they are less than a third as long. If these criteria are valid, then the wallacei, numata, doris, melpomene group are more prim- itive than the erato, sara, ricini group, for the wallacei group shows a more extensive distribu- tion of androconia, the possession of a signa, and the almost equal development of the dorsal and ventral processes of the paronychia, which are all features seen in other genera. If this is correct, then melpomene is more primitive than any member of the erato group. Furthermore, if melpomene and erato are very closely related, as genetical research suggests, then erato must be the most primitive of its own group. The relationships of the genera discussed and their constituent species, within the limits of this paper, are represented by a family tree in Text- fig. 153. Heliconius is undergoing a rapid, or, as Beebe, Crane & Fleming (1960) describe it, an explosive evolution, giving rise to a large number of rec- ognizable forms, some of which are biologically good species but many of which are not. The taxonomy of Heliconius has been complicated in the past by failure to recognize the significance of polymorphism and mimicry and by the use of characters which do not expose similarities due to convergence. The characters used in this paper, when applied to Heliconius as a whole, should help considerably to sort out the chaos in which the genus is at the moment. VI. Conclusions ( 1 ) . The Heliconiinae is a natural group and Michener’s (1942a) division into seven genera is reasonable and acceptable. (2) . The taxonomic characters used in this paper, which include the female foretarsi, the pretarsi, the venation, the androconia and their distribution, the female abdominal processes, the signa of the bursa copulatrix, the spermatheca and the male genital valves, are useful and applicable both to dried and fresh material. (3) . There are three principal divisions to the subfamily: (a) A central stem contemporarily repre- sented by the conservative Philaethria. (b) A diverse group containing Dryadula, which is the most distinct genus, and Agraulis and Dione and Podotricha which are closely related. (c) Dryas and Heliconius, of which Dryas is the single living representative of the common stem from which Heli- conius has evolved. (4) . Heliconius is in need of revision using valid criteria, but upon the examination of the nine species that occur in Trinidad there seem to be two principal divisions. One which contains H. aliphera and H. isabella (members of the old genus Eueides ) , which are primitive, and the rest, which seem also capable of division into the wallacei, doris, numata, melpomene group which is prob- ably older than the erato, sara, ricini group. VII. Summary The morphology of the Heliconiinae is de- scribed where relevant to the systematics of the subfamily. All the species of the genera other than Heliconius are included, but within Heli- conius material was confined to the nine species available in Trinidad. An interpretation of the evolutionary relation- ships within the subfamily is suggested, based upon the examination of characters which in- clude the pretarsi, the female foretarsi, the ven- ation, the structure and distribution of andro- conia, the signa, the spermatheca, the female abdominal processes and the male genital valves. VIII. References Alexander, A. J. 1961a. A study of the biology and behavior of the caterpillars, pupae and emerging but- terflies of the subfamily Heliconiinae in Trinidad, West Indies. Part I. Some aspects of larval behavior. Zoologica, 46:1-24. 1 fig. 1961b. Part II. Molting and the behavior of pupae and emerging adults. Zoologica, 46:105- 124. 1 fig. Bates, M. 1935. The butterflies of Cuba. Bull. Mus. Comp. Zool., 78:63-258. 1963] Emsley: Morphological Study of Imagine Heliconiinae 129 Beebe, W. 1955. Polymorphism in reared broods of Heli- conius butterflies from Surinam and Trini- dad. Zoologica, 40:139-143. Beebe, W., J. Crane & H. Fleming 1960. A comparison of eggs, larvae and pupae in fourteen species of heliconiine butterflies from Trinidad, W.I. Zoologica, 45:111- 154. 125 figs. Bodine, D. 1896. The taxonomic value of the antennae of the Lepidoptera. Trans. Amer. Ent. Soc., 23:1-56. Summary and Review by Tutt, Ent. Rec., 8:225-228. Bourgogne, J. 1951. In: Grasse, Traite de Zoologie, 10:174- 448, Paris. Brower, L. P., J. v. Z. Brower & C. T. Collins 1963. Experimental studies of mimicry. 7. Rela- tive palatability and Mullerian mimicry among neotropical butterflies of the sub- family Heliconiinae. Zoologica, 48:65-84. Brown, F. M. 1944. Notes on Mexican butterflies. II-IV. J. New York Ent. Soc., 52:99-119. Crane, J., & H. Fleming 1953. Construction and operation of butterfly in- sectaries in the tropics. Zoologica, 38:161- 172. Crane, J. 1954. Spectral reflectance characteristics of but- terflies (Lepidoptera) from Trinidad, B.W.I. Zoologica, 39:85-115. 1955. Imaginal behavior of a Trinidad butterfly, Heliconius erato hydara Hewitson, with special reference to the social use of color. Zoologica, 40:167-196. 1957. Imaginal behavior in butterflies of the fam- ily Heliconiidae: Changing social patterns and irrelevant actions. Zoologica, 42:135- 145. 8 figs. Doubleday, E., & I. O. Westwood 1846-1850. Genera of Diurnal Lepidoptera, Lon- don. Emsley, M. G. 1958. A technique for the examination of the feeding mechanism in phytophagous het- eroptera. Proc. R. Ent. Soc. Lond. (A), 33:93-94. Erlich, P. R., & A. H. Erlich 1962. The head musculature of the Butterflies (Lepidoptera: Papilionoidea). Microento- mology, 25:1-89. 316 figs. Fleming, H. 1960. The first instar larvae of the Heliconiinae (Butterflies) of Trinidad, W.I. Zoologica, 45:91-110. 5 figs. Fr acker, S. B. 1915. The classification of lepidopterous larvae. Illinois Biol. Monogr., II (1): 1-169. Godman, F. D., & O. Salvin 1879-1901. Biologia Centrali-Americana. Hall, A. A. 1921. Descriptions of three new butterflies from Colombia. Entomologist, 54:276-279. Hall, A. 1925. List of the butterflies of Hispaniola. En- tomologist, 58:161-165, 186-190. Hayward, K. I. 1952. Clave para los generos y especies argen- tinos de la familia Nymphalidae. Acta Zool. lilloana, Tucuman, 10:401-421. Imms, A. D. 1957. A general textbook of Entomology. Lon- don. Lorkovic, Z. 1956. Zavisnost variajabilnosti organa muskog genitalnog aparata kukoca a njihoroi funk- cionalnoj vrijednosti. (English Summary). Bioloski Glasnik, 7:234-5. Martin, L. M., & F. S. Truxal 1955. A list of north American Lepidoptera in the Los Angeles County Museum. Pt. 1, Butterflies. Publ. County Los Angeles Museum Zool., No. 8:1-35. Michener, C. D. 1942a. A generic revision of the Heliconiinae (Lepidoptera, Nymphalidae). Amer. Mus. Novit., No. 1197:1-8. 17 figs. 1942b. A review of the subspecies of Agraulis vanillae (Linneus) Lepidoptera: Nymph- alidae. Amer. Mus. Novit., No. 1215:1-7. Muller, F. 1877a. The “maracuja” [or passion flower] but- terflies. Stettin Ent. Zeit., 38:492-496. 1877b. The scent scales of the male “maracuja” butterflies. Kosmos, 1:391-395. 9 figs. 1878. The stink clubs of the female “maracuja” butterflies.” Zeit. Y/iss. Zool., 30:167-170. 8 figs. Neustetter, H. 1929. Heliconiinae. Lepidopterorum Catalogus. 36:1-135. Berlin. Randolph, V. 1922. A preliminary study of the life history and habits of Dione vanillae Linn. Trans. Kansas Acad. Sci., 30:351-362. 130 Zoologica: New York Zoological Society [48: 8: 1963] Riley, N. D. 1926. Colaenis and Dione (Lep. Nymphalidae) : a revisionary note on the species. Ento- mologist, 59:240-245. Rindge, F. H. 1952. The butterflies of the Bahamas Islands, British West Indies. Amer. Mus. Novit., No. 1563:1-18. 1955. The butterflies of the Van-Voast Amer. Mus. Nat. Hist. Expedition to the Bahama Islands B.W.I. Amer. Mus. Novit., No. 1715:1-20. 8 figs. Seitz, A. 1913. Heliconiinae. In: Macrolepidoptera of the World. 5:375-402; pis. 72-80, 84. Sheppard, P. M. Some genetic studies of Mullerian mimics in butterflies of the genus Heliconius. Zoologica, 48: (in press). Stichel, H. 1903. Synomymiches Verzeichnis bekannter Eui- edes- Forman mit erlauternden Bemerk- ungen und Neubeschrei bungen. Berl. Ent. Zeit., 48:1-34. 25 figs. Stichel, H. 1938. Nymphalidae. Lepidopterorum Catalogus, 86:1-374. Berlin. Stichel, H., & H. Riffarth 1905. Heliconiidae. Das Tierreich. Lief. 22:1- 290. Taylor, J. S. 1957. Notes on the proboscis in Lepidoptera. Ent. Rec., 69:25-29, 53-58. Torre y Callejas, S. L. de la 1949. A list supplementing Bates’ “Butterflies of Cuba.” Lepid. News, 3:65. Turner, I. R. G., C. A. Clarke & P. M. Sheppard 1961. Genetics of a difference in the male geni- talia of East and West African stocks of Papilio dardanus (Lep.). Nature, 191: 935-936. Turner, J. R. G., & J. Crane 1962. The genetics of some polymorphic forms of the butterflies Heliconius melpomene Linnaeus and H. erato Linnaeus. I. Major genes. Zoologica, 47:141-152. 1 pi. Wallengren, H. D. J. 1863. Wein. Ent. Monats., 7:65-76. Zerny, H., & M. Beier 1936-1938. In: Kiikenthal, Handbuch der Zoolo- gie, 4. Lepidoptera. Berlin. PLATE I Imagos of Heliconiinae from Trinidad. All the species are illustrated in color in Seitz: Macrolepi- doptera of the World; the American Rhopalocera, Vol. V, Plates (1924). Fig. 1. Dione juno. Fig. 2 . Agraulis vanillae. Fig. 3. Dryadula phaetusa. Fig. 4. Dryas iulia. Fig. 5. Philaethria dido. Fig. 6. Heliconius isabella. Fig. 7 .Heliconius aliphera. Fig. 8. Heliconius melpomene. Fig. 9. Heliconius numata. Fig. 10. Heliconius erato. Fig. 1 1 . Heliconius ricini. Fig. 12. Heliconius sara. Fig. 13. Heliconius Wallace!. Fig. 14. Heliconius doris. EMSLEY PLATE I A MORPHOLOGICAL STUDY OF IMAGINE HELICONIINAE (LEP.: NYMPHALIDAE) WITH A CONSIDERATION OF EVOLUTIONARY RELATIONSHIPS WITHIN THE GROUP Spontaneous Tuberculosis in Fishes and in Other Cold-blooded Verte- brates with Special Reference to Mycobacterium fortuitum Cruz from Fish and Human Lesions Ross F. Nigrelli & Henry Vogel* New York Aquarium (Plates I-VI) Introduction Interest in tuberculosis in cold-blooded ani- mals was stimulated by a report by Bataillon, Dubard & Terre in 1 897 on the disease in carp in a pond contaminated with dejecta from tuber- cular persons. It was later recognized that the acid-fast bacillus causing tuberculosis in the carp was a distinct species for which the name Mycobacterium piscium was given by Bataillon, Moeller & Terre (1902). The fact that this disease is found in fish led to speculations along the following lines: (1) that fish may be carriers of human tuberculosis organisms, (2) that fish, amphibians and reptiles could be used for the transmutation of human tuberculosis bacillus by serial passage, and (3) that these, or the acid- fast bacilli from cold-blooded animals, could be used for the treatment and prevention of human tuberculosis. The controversies engendered by discussions on these topics were reviewed by Vogel (1956, 1958) and by Parisot (1958). The relatively recent discoveries of atypical human pathogenic species, Mycobacterium for- tuitum Cruz (see Gordon, 1957) and Myco. balnei Linell & Norden (1954), have revived interest in this subject.** These atypical forms, which are also found in fish and in water, to- gether with the acid-fast bacilli causing tubercu- losis in the lower vertebrates, show certain basic similarities in morphological, cultural and bio- chemical characteristics. Of particular interest is the report by Ross & Brancato (1959) that •Bureau of Laboratories, New York City Department of Health. **See also Clark, H. Fred, & Charles C. Shepard, “Effect of Environmental Temperature on Infection with Microbacterium marinum (balnei) of Mice and a Number of Poikilothermic Species. Jour. Bact., 86 (5) : 1059-1069. Nov., 1963. one of the strains of acid-fast bacilli isolated in our laboratory (Nigrelli, 1953) from the Neon Tetra ( Hyphessobrycon innesi) is the same as Mycobacterium fortuitum, a pathogenic species first isolated from human and cattle lesions in South America. This paper deals with further information on the Neon Tetra strains of mycobacteria, tubercu- losis in other fishes in the New York Aquarium and with reports of the disease in fishes, amphib- ians and reptiles by other investigators. Tuberculosis in Fishes in the New York Aquarium Routine examinations of fish in the New York Aquarium and a search of the literature show that tuberculosis in poikilothermic animals is much more prevalent than is generally suspected. The host species are listed in Table IV. Table I lists those host species that were found infected in the New York Aquarium and from which the acid-fast bacilli were isolated and cultured. Pathology of Tuberculosis in Fishes Tubercular lesions are found in gills, skin, muscle, heart, kidneys, spleen, liver, pancreas, mesenteries, gonads, eyes and brain. Leproma- tous-like macular and necrotic skin and fin lesions are characteristic of tuberculosis in the Three-spot or Blue Gourami (PI. V, fig. 9). The disease in the Neon Tetra is recognized externally by yellowish discoloration of the usually brilliant red markings on both sides of the hind part of the body (Pis. I & II, figs. 1, 2, 3). Tn most species there is no external evidence but the disease is recognized internally by the presence of extensive, yellowish adhesions or by numerous miliary-like tubercle bodies in various organs (Pis. II, III, V & VI, figs. 4, 5, 10, 11). 131 132 Zoologica: New York Zoological Society [48: 9 Table I. Hosts from which Acid-Fast Bacilli Have Been Isolated (Cultures maintained at the New York Aquarium) Species Common Name j Habitat Tropical Freshwater spp. Hyphessobrycon innesi Trichogaster trichopterus Toxotes jaculator Tropical Marine spp. Plectorkynchus sp. Premnas aculeatus Amphiprion percula Amphiprion akallaopsis Amphiprion xanthurus Amphiprion laticlavius Neon Tetra Three-spot or Blue Gourami Archerfish Sweet-lip Spiny Clownfish Common Clownfish Skunk Clownfish Chocolate Clownfish White-saddle Clownfish Peruvian Amazon Tropical Far East Philippines & Far East Pacific coral reefs Pacific coral reefs Pacific coral reefs Pacific coral reefs Pacific coral reefs Pacific coral reefs In the Climbing Perch and in the Goldfish the lesions appear as numerous pearl-like bodies in the liver, kidneys and mesenteries (Pis. V & VI, figs. 10, 11). Emaciation, exophthalmia, lordo- sis and other body abnormalities may or may not be associated with the disease. Histopathologically, tuberculosis in fishes re- sembles the tubercular picture in warm-blooded animals but with the following differences: milder or no inflammatory reactions, greater fibrous development, absence of typical giant cells and little or no caseation (Pis. II & IV, figs. 3, 4, 7, 8). The term “hard tubercle” (Pis. V & VI, figs. 10, 11) appears appropriate for the lesions in the Climbing Perch, Goldfish and several other species. These tubercles are formed by coalescence of several smaller units (PI. VI, fig. 1 1 ) . In some freshwater fishes some degree of caseation may occur but typically the tissue reaction consists of loosely organized masses of semi-necrotic cells with groups of acid-fast bacilli in the core of epitheloid-like elements. (Pis. II&IV, figs. 3,7,8). The term “mycobacteriosis” was suggested by Parisot & Wood (1960) as being more appro- priate for tuberculosis in fish. The suggestion was based on the absence of typical inflamma- tory responses to the infection in salmonoid fishes. However, since this is not true for fishes generally and since typical tubercles and other classical tissues reactions are present, tubercu- losis is a valid term for the disease in fish as well as in other cold-blooded animals. Transmission Tuberculosis in cold-blooded vertebrates can be induced by parenteral injections of mycobac- terial suspensions. However, it is generally con- ceded that the natural mode of infection is by ingestion of the organisms directly from the water, by eating infected tissues or contaminated feed. Such origins of the infective organisms have been experimentally demonstrated for tuberculosis in tadpoles (Nonidez & Kahn, 1934, 1937)1, in the Mexican platyfish (Baker & Hagen, 1942) and in snails (Michelson, 1 96 1 ) 2. The increase in incidence of tuberculosis in hatchery-maintained salmon and trout is directly related to the increased usage of infected salmon carcass as feed for young salmon, a deterimental hatchery practice of which fishery biologists were unaware until recently (Wood & Ordal, 1958). The possibility of transovarian trans- mission or of the spread of the infection by con- tamination of sperms and eggs during stripping of mature stock fish or the spawning run fish was also considered. Although the results on the salmon studies were inconclusive (Ross & John- son, 1962), our observations of tuberculosis in embryonic platyfish and guppies certainly sug- gest transovarian transmission as a definite pos- sibility. In addition, the entry of infective organ- isms through lesions of the skin and gills caused by parasites or by mechanical injury should also be considered. There is no information on the mechanism of spread of tuberculosis in fish. If the portal of entry is through lesions in the skin, the route must be through the lymphatic system or through the blood stream. Since the preponderance of evidence indicates that the infection is brought about by ingestion, the spread must then take place through the gastro-intestinal tract. Just how this is accomplished has not been deter- mined, especially since we have not observed tubercular lesions in this organ (PI. II, fig. 4) . Hose F. Nonidez & Morton C. Kahn. Tuberculosis in- duced in the tadpole by feeding. Proc. Soc. Exp. Biol. & Med., 31 : 783. Experimental tuberculosis infection in the tadpole and the mechanism of spread. Amer. Rev. Tuberc., 36: 191. 2Edward H. Michelson. An acid-fast pathogen of fresh water snails. Amer. J. Trop. Med. & Hyg., 60: 423. 1963] Nigrelli & Vogel: Spontaneous Tuberculosis in Cold-blooded Vertebrates 133 Isolation and Cultural Procedures Isolation of the acid-fast bacilli from patho- logical materials in fishes is relatively simple. In the Neon Tetra, for example, the disease is readily recognized by the yellowish discoloration of the red markings. The fish is anaesthetized with urethane (methyl carbamate) or with MS- 222 (tricaine methanesulphonate, Sandoz), and the lateral body wall in front of the vent is cauterized with a red-hot scalpel; the flesh adhering to the blade results in a raised flap, exposing the body cavity. A sterile bacterio- logical needle is plunged into the lesions, prefer- ably into those in the kidneys, and the material is then transferred to slants of media ordinarily used to culture mycobacteria. In our laboratory, slants of Dorset’s or Petroff’s egg agar is used successfully. It is our experience that with this simple technique pure cultures of acid-fast bacilli are usually obtained. If difficulty is en- countered, however, a portion of the disease tissue is digested with 4% sodium hydroxide for 15-30 minutes to destroy the contaminating organisms. The digest is neutralized with HC1 and centrifuged. The sediment is then inoculated on one of the media suggested above. The digestion time with NaOH can be varied, de- pending on the sensitivity of the bacilli and the quantity of tissue to be digested. Diseased tissue can also be treated with trisodium phosphate, oxalic acid or with 6% sulfuric acid. Other tech- niques and media for handling tubercular fish tissue are suggested by Westgard (1959), and those found in any standard reference on meth- ods in pathology and bacteriology may also be used. Since contamination of fish material may reach a high level in a short time, it is suggested that moribund fish be sacrificed and used for the isolation procedures. Some Characteristics of Mycobacteria Isolated from Fishes in the New York Aquarium The mycobacteria are easily demonstrated in smears of the skin and organ lesions by the Ziehl-Neelsen staining method (Pis. I & III, figs. 2, 5). The bacilli, which may or may not be seen within macrophages, are pleomorphic slen- der rods varying in length from 3 to 7 microns and show the bead-like constituents in the cell when stained, or when seen in electron microscope preparations (PI. Ill, fig. 6). The organisms grow slowly as raised colonies on glycerol and egg agar slants when kept at room temperature. However, once growth is established, usually within one to three weeks, subcultures will grow more rapidly. Mycobacteria from tropical fishes grow well at 28 °C. and subcultures become luxuriant even at 37°C. (PI. VI, fig. 12) The degree of pigment production, which may de- velop either in light or in the dark, varies with the strain and age of the culture. The myco- bacteria isolated from freshwater tropical fishes grown on Dorset’s or Petroff’s media vary in color from cream to yellowish-green; bacilli from stenohaline tropical fishes vary from light to bright yellow color. Classification of Mycobacteria of Cold-blooded Vertebrates Table II list the species of mycobacteria from fishes, amphibians and reptiles that have been studied in detail; some of these are recognized as valid species and are included in Bergey’s Manual of Determinative Bacteriology. The growth and nutritional requirements, antigenic structure, pathogenicity, source and habitat of Mycobacterium piscium, Myco. mar- inum, Myco. ranae, Myco. thamnopheos and Myco. friedmanni are summarized by Reed (1948). Gordon (1957) recognizes and char- acterizes only Myco. marinum. Myco. platypoe- cilus, Myco. thamnopheos and Myco. fortuitum. The type of culture of Mycobacterium piscium is apparently lost while Myco. ranae and Myco. friedmanni, together with certain fish strains (e.g., from Halibut and Halibut roe), are con- sidered to be identical with Myco, smegmatis and/or with Myco. fortuitum (Gordon & Smith, 1955). The information on Mycobacterium anabanti Besse (1949a) and Myco. salmoniphi- lum Ross (1960) was not available at the time to Gordon and her co-workers for evaluation. However, Gordon & Mihm (1959) reported that certain of the strains from trout and salmon are identical with Myco. fortuitum. Except for the Neon Tetra strains, the myco- bacteria of the fish listed in Table I have not been further characterized. Ross & Brancato (1959) considered the Neon Tetra strain 9-21 H, which is a subculture of our H-strain, to be iden- tical with Mycobacterium fortuitum. Some dif- ferences in the utilization of several substances as carbon source are noted between strain 9-2 1H and strains H and N as anafyzed by Vogel (1959). These are shown in Table III and com- pared with Mycobacterium marinum, Myco. fortuitum from mammals and with the several strains of Myco. salmoniphilum which were rec- ognized as Myco. fortuitum by Gordon and Mihm (1959). Discussion As pointed out by Fregnan, Smith & Randall (1961), a great deal of attention has been 134 Zoologic a: New York Zoological Society [48: 9 Table II. Species of Mycobacteria of Poikilotherms Mycobacteria Mycobacterium piscium (see Reed, 1948) Mycobacterium marinum Aronson, 1926 Mycobacterium platypoecilus Baker & Hagen, 1942 Mycobacterium anabanti Besse, 1949a Mycobacterium jortuitum Cruz (see Gordon, 1957) Neon Tetra Strain 9-21 H (Ross & Brancato, 1959) Mycobacterium salmoniphilum Ross, 1960 Mycobacterium ranae (Kiister, 1905) (see Reed, Mycobacterium friedmanni Holland, 1920 (see Reed, 1948) Mycobacterium thamnopheos Aronson, 1929 Host I. Fishes Cyprinus carpio, European Carp Abudefduf mauritii, Sergeant Major Micropogon undulatus, Croaker Centropristis striatus, Sea Bass (Philadelphia Aquarium) Playtpoecilus maculatus, Mexican Platyfish (Cornell IJniv.) Macropodus opercularis, Paradisefish (France) Hyphessobrycon innesi, Neon Tetra (New York Aquarium) Oncorhynchus tschawytscha, Chinook Salmon Salmon gairdneri, Steelhead Trout (Hatcheries, Oregon & Washington) II. Amphibians European Frogs III. Reptiles Che lone corticata, Loggerhead Turtle (European Zoo) Thamnophis sirtalis, Garter Snake (U.S.A.) 1948) directed towards the difficult problem of differ- entiation and classification of saprophytic and pathogenic mycobacteria ever since the dis- covery of the tubercle bacillus by Robert Koch in 1882. No entirely satisfactory method has yet been developed and all attempts so far have led to considerable confusion. This is especially true for the attempts to classify the mycobacteria causing tuberculosis in fishes, amphibians and reptiles. For example, Gordon & Smith (1955) and Gordon & Mihm (1959) reported that several strains of mycobacteria from cold- blooded vertebrates were identical either with Mycobacterium smegmatis or Myco. jortuitum. Gordon (1957) considers Myco. marinum, Myco. platypoecilus and Myco. thamnopheos to be valid species. However, the discovery of Mycobacterium balnei in swimming pools and in human lesions (Linell & Norden, 1954; Swift & Cohen, 1962) has added to the confusion. Bojalil (1959) considers this species to be the same as Myco. marinum while McMillen & Kushner (1959) report that Myco. marinum, Myco. platypoecilus and Myco. balnei represent a single species which, by priority, should be Myco. marinum Aronson. In addition, McMillen (1960) indicates that Myco. jortuitum is a mutation or adaptation of Myco. marinum. If the above reports are valid, then all strains of mycobacteria from marine and freshwater fishes, regardless of ecological and other biologi- cal factors, belong to either Mycobacterium marinum originally described from Atlantic Coast fishes or to Mycobacterium jortuitum first reported from cattle and human abscesses. It is difficult to believe that either species is a ubiqui- tous pathogen of fish with no host specificity. In any event, it is quite apparent that tubercu- losis in cold-blooded animals, and especially in fishes, is much more widespread than is gen- erally suspected. Although tuberculosis has been found mainly in fishes kept in aquaria, hatcheries and in fish holding ponds, cases of tuberculosis in feral populations have been reported (Nigrelli, 1953). Of particular interest is the epizootics in salmonoids in the Pacific Northwest, both in hatchery-reared fishes and in migrating popula- tions (Wood & Ordal, 1958; Wood, 1959; Ross, 1959; Parisot & Wood, 1960). Tuberculosis in these species (Table IV), the presence of which was first reported by Earp, Ellis & Ordal (1955), is therefore of great economic importance. The disease is also prevalent in a large variety of tropical fresh water fishes. The members of the families Characidae and Cyprinidae, which are highly valued by fish hobbyists, are especially susceptible and commercially available to the microbiologist interested in this problem. Summary A survey of fishes in the New York Aquarium and a search of the literature show that tubercu- losis in these animals arid in other poikilotherms is more prevalent than is generally suspected. Table III. Carbon Sources Utilized by Mycobacteria from Fish 1963] Nigrelli & Vogel: Spontaneous Tuberculosis in Cold-blooded Vertebrates 135 X X x o © © o © © xooooooo X X X © © © © © O xooooooo X K X © © © © O © xooooooo I I I X X x XOOOO XOOOOOOO lll*ll®l|l|*l®lll| .a ja ja x x x o o .£P ooxooo |oo.£?oo.£Po X XOOOO© jooooooo XXX — •— iu I © O g >> 2 a -K a o « P» XOOOO© |0©000 I I xs FIG. 6 FIG. 5 SPONTANEOUS TUBERCULOSIS IN FISHES AND IN OTHER COLD-BLOODED VERTEBRATES WITH SPECIAL REFERENCE TO MYCOBACTERIUM FORTUITUM CRUZ FROM FISH AND HUMAN LESIONS NIGRELLI & VOGEL PLATE IV FIG. 8 SPONTANEOUS TUBERCULOSIS IN FISHES AND IN OTHER COLD-BLOODED VERTEBRATES WITH SPECIAL REFERENCE TO MYCOBACTERIUM FORTUITUM CRUZ FROM FISH AND HUMAN LESIONS FIG. 7 NIGRELLI & VOGEL PLATE V FIG. 10 SPONTANEOUS TUBERCULOSIS IN FISHES AND IN OTHER COLD-BLOODED VERTEBRATES WITH SPECIAL REFERENCE TO MYCOBACTERIUM FORTUITUM CRUZ FROM FISH AND HUMAN LESIONS FIG. 9 NIGRELLI & VOGEL PLATE VI FIG. It FIG. 12 SPONTANEOUS TUBERCULOSIS IN FISHES AND IN OTHER COLD-BLOODED VERTEBRATES WITH SPECIAL REFERENCE TO MYCOBACTERIUM FORTUITUM CRUZ FROM FISH AND HUMAN LESIONS NEW YORK ZOOLOGICAL SOCIETY GENERAL OFFICE 630 Fifth Avenue, New York, N. Y. 10020 PUBLICATION OFFICE The Zoological Park, Bronx, N. Y. 10460 OFFICERS PRESIDENT VICE-PRESIDENT SECRETARY TREASURER Fairfield Osborn Laurance S. Rockefeller George W. Merck David H. McAlpin SCIENTIFIC STAFF: William G. Conway. . Director, Zoological Park Christopher W. Coates. .Director, Aquarium John Tee- Van General Director Emeritus ZOOLOGICAL PARK Joseph A. Davis, Jr. . . Curator, Mammals Grace Davall Assistant Curator, Mammals and Birds William G. Conway . . Curator, Birds Joseph Bell Assistant Curator, Birds Herndon G. Dowling . Curator, Reptiles Charles P. Gandal. . . Veterinarian Lee S. Crandall General Curator Emeritus Roland Lindemann .... Consultant in Mam- mal Management AQUARIUM Paul Montreuil Curator Carleton Ray Associate Curator Ross F. Nigrelli Pathologist & Chair- man of Department of Marine Biochem- istry & Ecology Klaus D. Kallman. . . .Geneticist C. M. Breder, Jr Research Associate in Ichthyology Harry A. Charipper . . . Research Associate in Histology Sophie Jakowska Research Associate in Experimental Biology Louis Mowbray Research Associate in Field Biology GENERAL William Bridges . . Editor & Curator, Publications Dorothy Reville . . Editorial Assistant Sam Dunton Photographer Henry M. Lester . . Photographic Consultant DEPARTMENT OF TROPICAL RESEARCH Jocelyn Crane Director Associates: Jane van Z. Brower William K. Gregory Lincoln P. Brower Donald R. Griffin William G. Conway David W. Snow Julie C. Emsley John Tee-Van Michael G. Emsley AFFILIATE L. Floyd Clarke Director, Jackson Hole Biological Research Station EDITORIAL COMMITTEE Fairfield Osborn, Chairman William Bridges Joseph A. Davis, Jr. Christopher W. Coates Herndon G. Dowling William G. Conway Ross F. Nigrelli Lee S. Crandall ZOOLOGICA SCIENTIFIC CONTRIBUTIONS OF THE NEW YORK ZOOLOGICAL SOCIETY VOLUME 48 • ISSUE 4 • WINTER, 1963 The ZOOLOGICAL PARK, New York Contents PAGE 10. Some Genetic Studies of Mullerian Mimics in Butterflies of the Genus Heliconius. By P. M. Sheppard. Plates I & II 145 11. The Electroretinogram of Heliconius erato (Lepidoptera) and Its Possible Relation to Established Behavior Patterns. By S. L. Swihart. Plates I & II; Text-figures 1-6 155 12. The Display of the Blue-backed Manakin, Chiroxiphia pareola, in Tobago, W. I. By D. W. Snow. Plates I-III; Text-figures 1-3 167 Index to Volume 48 177 Zoologica is published quarterly by the New York Zoological Society at the New York Zoological Park, Bronx Park, Bronx, N. Y. 10460, and manuscripts, subscriptions, orders for back issues and changes of address should be sent to that address. Subscription rates: $6.00 per year; single numbers. $1.50, unless otherwise stated in the Society’s catalog of publications. Second-class postage paid at Bronx, N. Y. Volume 48, Issue 3 (Fall, 1963) was published December 26, 1963 Volume 48, Issue 4 (Winter, 1963) was published December 31, 1963 10 Some Genetic Studies of Mullerian Mimics in Butterflies of the Genus Heliconius ll 2 P. M. Sheppard Department of Genetics, University of Liverpool (Plates I & II) [This paper is a contribution from the William Bee,be Tropical Research Station of the New York Zoological Society at Simla, Arima Valley, Trinidad, West Indies. The Station was founded in 1950 by the Zoological Society’s Department of Tropical Re- search, under Dr. Beebe’s direction. It comprises 200 acres in the middle of the Northern Range, which includes large stretches of government forest re- serves. The altitude of the research area is 500 to 1,800 feet, with an annual rainfall of more than 100 inches. [For further ecological details of meteorology and biotic zones see “Introduction to the Ecology of the Arima Valley, Trinidad, B.W.I.” by William Beebe, Zoologica, 1952, Vol. 37, No. 13, pp. 157-184], Contents I. Introduction 145 II. Materials and Methods 145 III. Results 147 IV. Discussion 152 V. Summary 153 VI. References 153 I. Introduction The genetic study of Batesian mimicry is quite well advanced, particularly in the genus Papilio. The data so far amassed suggest that the evolution of this type of mimicry is initiated by the presence of a phenotype with an imperfect resemblance to the model, as a result of mutation. If the new mutant is estab- lished by selection, modifiers of it are accumu- lated, which improve the resemblance of the mimic to the model (Clarke & Sheppard, 1962) . The genetic investigations have been facilitated by the widespread occurrence of polymorphism ^Contribution No. 1042, Department of Tropical Re- search, New York Zoological Society. 2This study has been supported by the National Sci- ence Foundation (G21071). in Batesian mimics. Such polymorphisms would be expected on theoretical grounds, but in Mullerian mimicry they should not occur since the evolution of this type of mimicry should lead to monomorphism (Carpenter & Ford, 1933). Nevertheless, many Mullerian mimics, particularly in the genus Heliconius, are poly- morphic. A previous study (Turner & Crane, 1962), together with the present one, were started to gather data on the mode of inheritance of some of these polymorphic forms— data essen- tial to any subsequent work on the evolution of Mullerian mimicry in general and the main- tenance of polymorphisms in such mimetic spe- cies in particlular. II. Materials and Methods The species investigated genetically are the South American butterflies Heliconius numata, Heliconius doris, Heliconius melpomene and Heliconius erato. The technique of hand-mating butterflies (see Clarke & Sheppard, 1956) has proved extremely useful in genetic investigations of Batesian mimicry, since it has often allowed one to obtain species hybrids which could not otherwise have been produced. It has the further advantage of eliminating the necessity of having large mating cages. Since the study of Mullerian mimicry will often require the production of species hybrids, attempts were made to hand-mate members of the Heliconiinae. It was found that Dione juno, which will not readily pair in insectaries or lay eggs in them, could be hand-paired without much difficulty. The mated females would lay eggs in black silk organza sleeves placed over their food plant, Passiflora serrato-digitata. How- ever, since the butterfly is not polymorphic, no further work was done with it. It was also found 145 146 Zoologica: New York Zoological Society [48: 10 that H. numata and H. erato could be hand- paired and H. erato could be induced to lay eggs in silk organza sleeves. However, since the species proved refractory with respect to both the techniques, these methods were abandoned. Only one mating reported here, that between two H. numata, was obtained by hand-mating. All the broods of H. melpomene and H. erato were bred by the methods described by Turner & Crane (1962). The insects were placed in large insectaries and the females were allowed to lay eggs on cut food plant in their cages. The eggs were collected every evening and each egg was placed in a separate labelled dish and from then on each individual was kept isolated from all others. H. doris has not yet been mated successfully in insectaries, since it requires a very tall cage to fly in. Nor would it lay eggs in the cages available or in silk organza bags, although one female did lay two eggs in such a bag. It is fortunate, therefore, that the species does not lay eggs singly, but deposits them in large rafts, of fifty to one hundred and fifty eggs (Beebe, Crane & Fleming, 1960). Consequently, to in- vestigate the genetics of H. doris, egg rafts were collected in the wild and the resulting larvae were reared on cut food plant in jars of water in the laboratory. Origin of Breeding Material and Description of Forms The specimens of H. numata used in this study were taken from a colony living by the sides of Andrew’s Trace, ten miles from Arima near the pass on the Arima-Blanchisseuse Road, Trini- dad. A small random sample of adult butterflies was collected by netting them as they flew across the Trace running through the colony. The pair of insects used for the hand-mating and breed- ing came, however, from a stock raised in the insectaries. This stock originated from eggs and larvae collected off the food plant of the species on Andrew’s Trace. There are two forms of H. numata in Trini- dad, a brown one which has yellow near the apex of the forewing, but none on the hindwing, and a yellow form which has an increased amount of yellow on the forewing and a yellow stripe on the hindwing which replaces a brown one of the other form (Plate I). There are a number of other minor differences of pattern with which we need not concern ourselves here. The H. doris broods reported in this paper were all collected as egg rafts in the wild in Trini- dad, except Brood 5 which was taken as a tight group of 2nd instar larvae. Broods 1 and 2 were found on the Texaco oil field near Guaya- guayare, and Broods 3, 4 and 5 were found near Arima. In the case of Brood 4, the female was actually seen to be laying eggs when the egg raft was first discovered. There are three main forms of H. doris in Trinidad, but the commonest form appears to be the “blue” one, doris. This has the usual black forewing with the two yellow patches on it (Plate I) and a black hindwing with a blue basal area from which short blue rays extend into the black area. The second form is the “red” one, delila. This is like the blue form except that there is no blue but in contrast there is a red area at the base of the forewings and the hindwings. From the basal red area on the hindwings, red rays extend out towards the margin of the wings. These rays are far longer than the blue ones of the “blue” form. The third form is the “green” one, viridis, and it is much like the blue phenotype except that the blue is replaced by green or blue-green. The H. melpomene were obtained from two sources, Trinidad and Surinam. The Trinidad material was obtained as live adult butterflies caught near Arima. The Surinam insects came from Moengo. They were obtained as eggs, larvae, or adult butterflies from the vicinity of the old mine, the new mine and the wharf at Moengo itself. In Trinidad the species is monomorphic for the broad-banded form which has black fore- and hindwings with a broad red band near the apex of the forewings (Plate II) . In Surinam the species is highly polymorphic and among the many forms there are six main types, five of which are described and figured by Turner & Crane (1962). Besides the broad-banded Trini- dad form, there is an extremely similar form but with a narrow band on the forewings instead of a broad one (narrow banded). The third form, broad-banded dennis, is similar to the broad- banded form except that there is an extra red area at the base of the fore- and hindwings. The fourth form, narrow-banded dennis, is similar to dennis except that it has a narrow band near the apex of the forewing instead of the normal broad one. The fifth form, broad-banded radiate, is like broad-banded dennis but in addition has red ray- like marks extending from the basal red area of the hindwings and the sixth form, narrow- banded radiate, is similar to broad-banded ra- diate except that it has a narrow band near the apex of the forewing. Thus the six forms consist of three main patterns, banded, dennis and ra- diate, in each of which the band common to all can be either broad or narrow (Plates I & II) . The H. erato were obtained in the same places and the same manner as were H. melpomene. In Trinidad H. erato is monomorphic; the form 1963] Sheppard: Genetic Studies of Mullerian Mimics in Heliconius 147 found there, the broad-banded form, is so close in appearance to the local H. melpomene that only an expert investigator can tell them apart. In Surinam there are forms which parallel those of H. melpomene. Besides the broad-banded form there is a second which in some ways re- sembles narrow-banded in H. melpomene and in consequence we have called it narrow-banded. However, although the amount of red appears to be reduced in this form, this is achieved by an invasion of black pigment into the red bar rather than by a distinct narrowing of the bar itself. There are two other forms equivalent to dennis with broad bands and dennis with “narrow bands,” but we have not, as yet, found these in the wild. In H. erato, dennis differs from the similar form in H. melpomene in that there is no red basal area on the hindwing. The fifth form is broad-banded radiate which has the H. erato broad-banded dennis pattern with the ad- dition of rays on the hindwing. These rays are longer and of a different shape from those in the equivalent form in H. melpomene. The sixth form is like broad-banded radiate, but has nar- row bands of the erato shape (Plates I & II) . III. Results H. numata In Table I are given the results of hand-mating a virgin female H. numata with a male of the same species, both being of the yellow form. Not only the yellow but also the brown form of the species appeared among the offspring, show- ing that brown is recessive. There is no evidence of sex-linkage but the ratio of yellow to brown departs significantly from the 3 : 1 ratio expected on the simple hypothesis that the two forms are controlled by a pair of autosomal allelomorphs (Xi = 11.11 p<0.01). The proportions do not differ significantly from the 2:1 ratio expected if the homozygous yellow individuals are lethal (Xi = 3.37). This hypothesis cannot be accepted as it stands, however, because homozygous yel- low individuals almost certainly exist in na- ture. In one of the insectaries a number of yellow wild H. numata females were allowed to lay eggs. Over a period of days they produced 15 yellow offspring and no brown ones, which is a significant excess of yellow over the expected 2:1 ratio if all yellow females were heterozygous and were mated with heterozygous yellow males, let alone the ratio expected if some of the males had been homozygous browns. Since the two yellow parents in the brood came from the in- sectary, they may have been the offspring of the same parents. If this be so and if one of the parents had been carrying a lethal gene closely linked to the allelomorph controlling yellow, a 2:1 ratio would not be unlikely. There is a second hypothesis which must also be considered. The observed ratio is very close to the 9:7 ratio expected from a modification of the 9 : 3 : 3 : 1 ratio due to epistasis where brown is recessive and controlled at two independent loci. Only more genetic work could distinguish between the hypothesis of a lethal and that of two independent loci with epistasis. Before the breeding results had been obtained, it was decided to take a random sample from the wild population at Andrew’s Trace in order to estimate the gene frequencies. The sample is given in Table II. Although gene frequencies cannot now be estimated, the data suggest that the frequency of brown may be increasing in Trinidad. Kaye (1921) reported that the brown Table II. Random Sample of H. numata from Andrew’s Trace, Arima Valley, Trinidad, Taken between 16 Aug. and 17 Sept. 1962 Form Male | Female Total Yellow 24 10 34 Brown 6 5 11 form was very rare in Trinidad in the past. He said “Until recent years the dark forms without yellow in the hind wing and with reduction of yellow in the fore wing were only rarely met with and in fact I never saw such absolutely typical numata from Trinidad until this year.” It is true that the population referred to by Kaye is some fourteen miles from Andrew’s Trace, but it is situated on the same range of mountains and the insect is a powerful flier, so that the two pop- ulations are not likely to be very effectively isolated. Table I. Breeding Data for H. numata Form of Parents Form of Offspring Male Female Male Female Total Yellow Brown Yellow Brown Yellow Yellow 11 15 15 7 48 148 Zoologica: New York Zoological Society [48: 10 Table III. Breeding Data from H. doris. Broods Collected as Egg Rafts in the Wild in Trinidad, Sept. 1962 Brood Form Blue Red Green 1 68 — — 2 Male 11 Male 6 Female 14 Female 10 — 3 40 — — 4 12 — 10* 5 Male 53 Male 57 Male 1 Female 33 Female 26 Female — *One was intermediate. H. doris The broods resulting from egg rafts of H. doris found in the wild in Trinidad are given in Table III. Two of the broods did not segregate, giving only the blue form. Nos. 2 and 5 segre- gated for the red form, and No. 4 for the blue and green forms with one intermediate. The clear-cut segregation in Broods 2 and 5 indicates that red is inherited on a simple Men- delian basis. The ratio in Brood 2 suggests a difference from a ratio of three blue to one red (p=^0.05), expected if red is recessive (see be- low) and it is far closer to a 1 : 1 ratio (x =1.98). Brood 5 shows a very close approach to a 1:1 ratio of red to non-red, and is different from a 3:1 ratio (p<0.001). The single green individual may be genetically blue since it is not very ex- treme (but see below) . H. doris tends to fly rather high and very fast and is therefore difficult to catch. It has not been easy to obtain a random sample to determine the frequency of the various morphs. However, a number of these insects were caught in both Trinidad and Surinam. To augment the sample, a record was kept of all other specimens which were seen but not caught (Table IV). It is re- alized that such a procedure may allow an in- dividual butterfly to be counted more than once, but with such a powerful flier, not many indi- viduals are likely to be so counted. The data, such as they are, indicate that the frequency of the red form is low, and that the green form is even rarer in Trinidad. The data indicate, but do not prove, that the red form is somewhat commoner in Surinam. However, the segregation of red in 2 out of 5 broods indicates a higher frequency than that found for red in the random sample from Trinidad. If the frequency of the red form is low, then the most likely mat- ing to produce a segregating brood is between two heterozygotes (giving a 3:1 ratio) if red is recessive, but a back-cross (giving a 1 : 1 ratio) if red is dominant. It seems probable that both segregating broods are giving a 1 : 1 ratio and that it is likely therefore that red is dominant to blue, although more data are required to substantiate this point.3 The brood segregating only for the blue and green forms also appears to be a back-cross (al- though not significantly different from a 3:1 ratio), and since green is even rarer than red in Trinidad, it seems likely that green is also domi- nant to blue. In neither segregating brood can egg rafts of mixed parentage explain the ap- proach to a 1:1 ratio. Both the red and green forms appear to be rarer than blue in Trinidad and consequently if two or more females had 3Three additional broods were obtained in Sept., 1963, and produced the following phenotypes: No. 6, 16 red cf, 13 red 9; No. 7, 19 red 0.05). know if it is a complete dominant. It was pos- sible to show that rays on the hindwing are not controlled by an independent locus, which only produces its effect in the presence of the dennis pattern, since the dennis pattern and the presence or absence of rays did not segregate independ- ently in the back-cross to the Trinidad broad- banded form (Broods K.18, K.21, K.22, K.23). It might be argued that the Trinidad race is homozygous for the gene producing rayed hind- wings, but that it produces no effect because dennis is not found in that race. However, a male that produced a 1 : 1 ratio of radiate to non-radi- ate individuals when mated to a radiate female, produced a brood which segregated in a 1 : 1 ratio for dennis and non-dennis, when mated to a dennis individual (Broods K.23, K.24). Thus it is clear that the male was not carrying an allelomorph, at an independent locus, producing rayed hindwings only in the presence of dennis. In those back-cross broods appropriate for show- ing crossing-over between dennis and rays, there is no certain indication that the dennis pattern and rays are separated by crossing-over. It is true that the dennis pattern did appear in such a brood (K.22) but I attribute this to a mistake rather than a cross-over, since no individuals without dennis but with rays on the hindwings (the other cross-over class) appeared. Thus the data support that of Turner & Crane (1962) in suggesting that the dennis and ray patterns are controlled by two very closely linked genes, or perhaps by allelomorphs at one locus. Narrow Bands A number of narrow-banded forms, indistin- guishable morphologically from those described by Turner & Crane, were obtained from Moengo where they had obtained their butterflies. How- ever, the narrow-banded form I obtained is not recessive, since it produced such forms in the cross with the monomorphic Trinidad race. Moreover, broad-banded forms were obtained among the progeny of parents, both of which were narrow-banded (Broods C.3, C.ll). These broods also produced insects which had much more yellow on the forewings than is usual in narrow-banded forms. If such broods are divided into broad-banded forms, narrow-banded ones and narrow-banded ones with an excess of yel- low, a good approach to a 1 : 2 : 1 ratio is obtained (Xa = 2.28 p > 0.3), indicating that narrow bands are incompletely dominant (Table VI). One of these yellow individuals proved to be a homozygote on back-crossing to a heterozygote, and its offspring segregated out in a 1 : 1 ratio for narrow-band and narrow-band with excess yel- low (Table VI) . A few undoubted narrow-banded 150 Zoologica: New York Zoological Society [48: 10 Table V. Breeding Data from H. melpomene Brood Parents and Origin Phenotype of Offspring Total BR 8 9 BD 8 9 B 8 9 NR 8 9 ND 8 9 N 8 9 Female Male C.l T.B. S.N 0 1 0 0 6 7 0 0 0 0 2 2 18 C.3 S.N. S.N1 0 0 0 0 1 2 0 0 0 0 3 3 9 C.4 S.BD S.N1 0 0 1 0 0 0 0 0 0 0 0 0 1 C.4b Ci.N S.BR 3 2 0 0 4 5 1 3 0 0 4 1 23 C.l S.BD S.N1 0 0 1 4 1 6 0 0 3 1 1 3 20 C.8 S.BR S.N2 13 23 0 0 14 16 10 26 0 0 15 23 140 C.9 S.BD S.N2 0 0 2 6 3 2 0 0 10 8 9 8 48 C.10 S.N S.N2 0 0 0 0 0 0 0 0 0 0 4 3 7 C.ll S.N S.N2 0 0 1 0 5 5 0 0 0 1 7 6 25 C.12 S.BD S.N3 0 0 3 1 2 0 0 0 1 2 3 1 13 C.13 S.ND T.B 0 1 1 0 4 3 0 0 3 4 5 4 25 C.14 S.B S.BR 0 1 0 0 0 0 0 0 0 0 0 0 1 C.17 S.BD S.N1 0 0 0 0 0 1 0 0 1 0 0 0 2 K.4 Cg.N C12.N 0 0 0 0 0 0 0 0 0 0 27 23 50 K.6 C8.BR S.N3 17 13 0 0 13 10 14 16 0 0 4 11 98 K.10 C13.ND T.B 0 0 1 4 2 4 0 0 1 2 2 2 18 K.ll C7.ND C8.B 0 1 3 4 12 5 0 0 7 10 2 3 47 K.12 C9.B C7.ND 0 0 8 9 7 9 0 0 13 15 8 11 80 K.14 C7.BD S.N2 0 0 7 12 8 14 0 0 13 13 13 11 91 K.17 C8.NR C7.B 3 3 0 0 1 3 0 2 0 0 2 0 14 K.18 C8.NR T.B4 2 3 0 0 5 2 5 4 0 0 2 4 27 K.20 C8.NR Cll.B 3 3 0 0 4 6 4 3 0 0 3 3 29 K.21 C8.BR T.B4 9 6 0 0 3 6 0 0 0 0 0 1 25 K.22 C8.NR T.B5 10 7 0 1 6 10 9 7 0 0 13 6 69 K.23 K.6.BR T.B5 6 4 0 0 8 18 0 0 0 0 0 2 38 K.24 K.14.BD T.B5 0 0 11 12 16 15 0 0 0 0 0 1 55 In the Table, S and T indicate the origin of the parents as Surinam and Trinidad respectively. Elsewhere the origin of the parent is indicated by its Brood number. The letters BR, BD, B, NR, ND and N stand respectively for the phenotypes broad-banded radiate, broad-banded dennis, broad-banded (the Trinidad phenotype), narrow- banded radiate, narrow-banded dennis and narrow-banded. When a male has been used in more than one mating, it is distinguished by a superscript; thus the male parent of Broods K.22, K.23 and K.24 was the Trinidad broad-banded male No. 5. There are clearly a few insects which have been included in the wrong broods by mistake— an almost unavoidable occurrence when breeding such large numbers of insects. These are indicated by being placed in italics. heterozygotes in other broods have as much yellow on them as do some of the least extreme of the presumed homozygotes. Thus it seem likely that the heterozygotes and the homozy- gotes cannot always be distingished. That the narrow-banded forms in the broods reported here are different from the similar forms investigated by Turner & Crane is demonstrated by the linkage data as well as by the difference in the dominance relationships discussed above. The locus determining the narrow-banded form investigated by Turner & Crane was linked to that controlling the dennis pattern, whereas the present data give no indication of linkage be- tween narrow-bands and either the dennis or the radiate patterns. Thus there are clearly two in- dependent loci, both of which have allelomorphs producing a narrow-banded form. H. erato Turner & Crane demonstrated from Beebe’s (1955) data that the radiate pattern in H. erato is dominant to the non-radiate form and that the dennis and rayed components of the patterns are inherited together. The present data (Table VII) are in complete accord with this interpretation. Turner & Crane also showed that the narrow- banded form (which differs from that in H. mel- pomene, since the apparent reduction in red is achieved by an invasion of black pigment and not by a narrowing of the bar itself) is dominant to the broad-banded form. They also suggested that the locus concerned is linked to that con- trolling the radiate pattern. Our data confirm the dominance of “narrow-bands”, since a 1 : 1 : ratio was obtained in the back-cross to the monomor- phic Trinidad race. However, in the brood in question (E.C.2) there is no evidence of linkage. Since the previous evidence for linkage was not statistically significant, there is no reason to post- ulate its presence on the evidence from the breed- 1963] Sheppard: Genetic Studies of Miillerian Mimics in Heliconius 151 Table VI. Breeding Data from Narrow-banded H. melpomene Parents form and origin Female Male Phenotype of Offspring Total B N NY Male Female Male .Female Male Female C.3 S.N S.N 1 2 1 1 2 2 9 C.10 S.N S.N2 0 0 2 3 2 0 7 *C.ll S.N S.N2 5 5 6 2 1 4 23 Total 13 15 11 39 K.4 C.3. NY C.12.N 0 0 18 8 9 15 50 NY signifies that the narrow-banded form had more than the usual amount of yellow in the vicinity of the red narrow band. *The broad-banded and the narrow-banded dennis individuals have been excluded since their presence is clearly due to a mistake (in Table V). Table VII. Breeding Data from H. erato Brood Parents and origin Phenotype of Offspring Total BR B NR N IFemale Male Male Female Male Female Male Female Male Female EC.2 S.NR T.B 2 3 4 3 1 3 1 4 21 EK.14 EC2.NR T.B 0 0 1 0 0 0 0 0 1 EC.l S.BR S.? 1 0 0 1 0 0 0 0 2 EC.8 S.B S.BR 2 1 0 1 0 0 0 0 4 EC. 9 S.BR T.B 3 1 3 5 0 0 0 0 12 Table VIII. Phenotypes in Random Samples of H. melpomene and H. erato Taken as Adults (A) and as Eggs and Larvae (E & L) Species Stage Sex Phenotypes Total BR BD B NR ND N Male 0 0 12 0 0 2 H. melpomene Female 1 0 6 0 0 0 21 E & L Ma^e 4 5 43 0 0 7 Female 2 6 53 0 1 6 127 Total 7 11 114 0 1 15 148 Male A and 5 0 40 4 0 6 55 H. erato Female _ — . . _ Male 3 0 5 0 0 1 h &L Female 2 0 4 2 0 1 18 Total 10 0 49 6 0 8 73 mg data, nor to doubt that the same allelomorph was used in the two investigations. Random Samples of H. melpomene and H. erato from Surinam The forms found in H. melpomene and H. erato at Moengo in Surinam between July 21 and August 3, 1962, are given in Table VIII. Each sample is divided into two groups consist- ing of those insects taken as adult butterflies and those found as either eggs or larvae. The two do not differ significantly from one another al- though there is a suggestion that there are more radiate forms among the egg and larval sample in H. erato than among the adults. This can hardly be due to non-random sampling of adults 152 Zoologica: New York Zoological Society [48: 10 since it is precisely the rare conspicuous radiate forms that the collector would tend to net if his collecting were not random. Of course, during the sampling every effort was made to keep the sample random. From the random samples, estimates of the gene frequency can be made. For this purpose it has been assumed that in H. melpotnene the forms non-dennis, dennis and radiate are con- trolled by three allelomorphs d, D, and DR re- spectively and that all the narrow-banded forms are of the “dominant” type, controlled by a pair of allelomorphs NN (narrow-banded) and NB (broad-banded). In H. erato, the allelomorph for the non-radi- ate pattern has been designated as d, and that for the radiate form as DR. The allelomorph con- trolling the narrow-banded form is designated Bh following Turner & Crane and that for broad- banded B. The gene frequencies estimated from the ran- dom samples are given in Table IX. No standard errors have been attached to these estimates since the method of sampling eggs and larvae might have resulted in an excess of offspring of some parents being included. However, the insects are powerful fliers and only lay between one and eight eggs a day, each being laid on a separate vine and not in quick succession. Thus there is little likelihood that the eggs and larvae sampled are not random with respect to the population in the locality. IV. Discussion The very incomplete data on the inheritance of the morphs in H. numata and H. doris do not allow one to draw many conclusions on the factors responsible for the evolution and main- tenance of the polymorphisms. However, if the red and green forms of H. doris are, in fact, dominant, then the mechanism maintaining the polymorphism is of acute interest, since at least the frequency of the gene controlling the green form must be very low in Trinidad. Robertson (1962) has argued that under these circum- stances, the polymorphism cannot be maintained by the advantage of heterozygotes in small pop- ulations. Furthermore he says “If the equilibrium gene frequency lies outside the range of 0.2 and 0.8 selection for the heterozygote may over a large range of population sizes in fact magnify the effect of reduced population size in leading to fixation.” If Robertson is correct, it seems likely that the polymorphism for the green form in H. doris is maintained by some other mech- anism than heterozygous advantage, since in Trinidad the population of this species is ex- tremely sparse in some seasons. The elucidation of this mechanism, which can hardly be hybrid- ization with other races since Trinidad is an island, would be of extreme importance to the theory of Mullerian mimicry. The two species H. melpomene and H. erato show remarkable parallel variation with respect to their forms. But although the forms look much alike, they are morphologically different. Thus the apparent reduction of red in the nar- row-banded form in H. erato is obtained by an invasion of black pigment into the red sub-apical band, whereas in H. melpomene it is by a nar- rowing of the band itself. The morphology of the rays in the radiate forms is also different in the two species, as is the distribution of red in the dennis pattern (Plate II). The genetic control of the forms in the two species shows great similarities. In both species the radiate pattern is “dominant” and the dennis pattern and the rays are inherited together. Moreover, in both species there is a gene un- linked to that controlling the radiate pattern, which is dominant in effect and which reduces the amount of red on the forewing sub-apical bar. The recessive form of this phenotype, which is found in H. melpomene, has not yet been found in E. erato. The more extensive data on the genetics of Table IX. Gene Frequencies Estimated from Random Samples of Surinam H. melpomene and H. erato Species Allelomorph Frequency No. in Sample DR 0.024 D 0.041 148 H. melpomene d 0.935 NN 0.056 148 NB 0.944 DR 0.116 73 H . erato d 0.884 Bb 0.101 73 B 0.899 1963] Sheppard: Genetic Studies of Mullerian Mimics in Heliconius 153 H. melpomene and H. erato show quite clearly that the genes controlling dominant characters in Surinam are at such low frequencies that the polymorphism falls into the category which Robertson believes cannot be maintained by an advantage of heterozygotes. The maintenance of the polymorphism in Surinam in fact may not be controlled by the action of selection in the area itself, but may be due to hybridization, since the frequency of the rarer forms appears to increase towards the east and decrease towards the west. If hybridization is important in this respect, it could explain another puzzling feature of the polymorphism. The heterozygotes for narrow band, dennis and radiate in H. mel- pomene and the narrow-banded and radiate forms in H. erato look very much the same in the F.l Trinidad hybrids as they do in the pure Surinam stock. However, if there has been selec- tion for an improved resemblance between par- allel forms in the two species, owing to the mimicry, some breakdown in the pattern might have been expected (see Clarke & Sheppard, 1963). However, if the Surinam population is in reality itself a hybrid population, no such breakdown in the mimicry would be obtained. Only work on the genetics of populations to the east and to the south of Surinam can resolve these problems. V. Summary 1. The mode of inheritance of some of the polymorphic forms of the mimetic butterflies Heliconius numata, H. doris, H. melpomene and H. erato is described. 2. It was found that the Trinidad form of H. numata with yellow on the hindwings is domi- nant to that with no yellow. However, the exact mode of inheritance of the difference is not yet known, although certainly it depends on one or more major genes. 3. Data are presented which suggest, but do not prove, that in Trinidad the red and green forms of H. doris are dominant to the blue form. 4. It was confirmed that the “dennis” form of H. melpomene from Surinam, which has a red area at the base of the forewings and the hindwings, is dominant to “non-dennis.” It was also shown that the radiate form from the same place, in which there are red rays on the hind- wing in addition to the “dennis” pattern, is dominant or semi-dominant to its absence. 5. In previous work on the polymorphic Surinam population of H. melpomene, it had been shown that the form in which the red sub- apical forewingband is narrow (narrow-banded) is recessive to the broad-banded form (the only one in Trinidad) and controlled by a locus linked to that determining the “dennis” pattern. In the present investigation, an independent locus was identified which controlled a second narrow- banded form. This new form is semi-dominant, the heterozygote being indistinguishable pheno- typically from the recessive form. 6. It was confirmed from Surinam stock that the “radiate” pattern of H. erato is dominant to “non-radiate.” Furthermore, the narrow- banded form of H. erato, in which black invades the red sub-apical band, is dominant to broad- banded, the only form in Trinidad. However, it is not linked to the locus controlling the “radiate” pattern as had previously been sug- gested. 7. The frequency of the allelomorphs con- trolling the dominant forms of H. melpomene and H. erato in Surinam suggests that the poly- morphism may not be maintained by an advan- tage of the heterozygotes. It is suggested that the polymorphism results from hybridization between populations to the east and to the west of that country. It is pointed out that hybridiza- tion cannot explain the maintenance of the poly- morphism in H. doris in Trinidad. Acknowledgments I am very grateful to C. A. Clarke and J. R. G. Turner, who read the manuscript in detail, and to Mr. Turner for information about the geo- graphic distribution of some of the polymorphic forms of Heliconius. Appreciation goes also to Jocelyn Crane, Director of the Department of Tropical Re- search, New York Zoological Society, for facili- tating the study at the William Beebe Tropical Research Station in Trinidad, and for continu- ing to maintain some of the stocks following my departure. Special thanks are due the Station’s laboratory assistants, Kathleen Campbell, Jessie Lai-Fook Hsu and Thomasina Lai-Fook, for their careful work in the rearing of the broods. VI. References Beebe, W. 1955. Polymorphism in reared broods of Heli- conius butterflies from Surinam and Trini- dad. Zoologica, 40:139-143. Beebe, W., Crane, J. & Fleming, H. 1960. A comparison of eggs, larvae and pupae in fourteen species of heliconiine butter- flies from Trinidad, W.I. Zoologica, 45:111-154. Carpenter, G. D. H., & Ford, E. B. 1933. Mimicry. Methuen, London. 154 Zoologica: New York Zoological Society [48: 10: 1963] Clarke, 1956. 1962. 1963. Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Fig. 8. C. A., & Sheppard, P. M. Hand-pairing of butterflies. Lepidopte- rists’ News, 10:47-53. Disruptive selection and its effect on a metrical character in the butterfly Papilio dardanus. Evolution, 16:214-226. Interactions between major genes and polygenes in the determination of the mimetic patterns of Papilio dardanus. Evo- lution (in press). Kaye, W. J. 1921. A catalogue of the Trinidad Lepidoptera Rhopalocera (Butterflies). Mem. Dept, of Agriculture, Trinidad and Tobago, No. 2. Robertson, A. 1962. Selection for heterozygotes in small popu- lations Genetics, 47:1291-1300. Turner, J. R. G., & Crane, J. 1962. The genetics of some polymorphic forms of the butterflies Heliconius melpomene Linnaeus and H. erato Linnaeus. I. Major genes. Zoologica, 47:141-152. EXPLANATION OF THE PLATES Plate I H. doris, red form from Brood 2. H. doris, blue form from Brood 2. H. numata, brown form from Brood (Table I). H. numata, yellow form from Brood (Table I). H. melpomene, “dennis” form collected as a larva in Surinam. H. erato collected as an egg from Surinam. This insect shows a tendency towards nar- row bands, but it is phenotypically dif- ferent, and may be genotypically different from the true narrow banded form of H. erato (see Plate II, Fig. 12). Plate II H. melpomene, broad-banded form from Surinam. H. erato, broad-banded form from Sur- inam. Note the close resemblance to the corresponding form in H. melpomene (Fig. 7). Fig. 9. H. melpomene, “radiate” form from Sur- inam. Compare the pattern with that of “dennis” (Plate I, Fig. 5), and ‘“radiate” of H. erato (Plate II, Fig. 10). Fig. 10. H. erato, “radiate” form from Surinam. Note the difference between the rays in this insect and those in H. melpomene (Fig. 9). Fig. 11. H. melpomene, narrow-banded heterozy- gote from Surinam. Compare with the cor- responding homozygotes (Fig. 7 and Fig. 13). Fig. 12. H. erato, narrow-banded from Brood EC.2. Note the difference between this form and narrow-banded in H. melpomene (Fig. 11). Fig. 13. H. melpomene, narrow-banded homozy- gote from Brood C.ll. Note the difference between it and the heterozygous form (Fig. 11). The very pale areas are yellow and bordered towards the apex of the wing by a narrow red band. This band appears as a gray area in the photograph. Except in Fig. 13, all the pale areas of the insects shown are red. SHEPPARD PLATE I FIG. 3 FIG. 4 FIG. 5 FIG. 6 m m FIG. 2 FIG. I SOME GENETIC STUDIES OF MULLERIAN MIMICS IN BUTTERFLIES OF THE GENUS HELICONIUS SHEPPARD PLATE II FIG. 9 FIG. 10 FIG. 1! FIG. 12 FIG. 13 m m SOME GENETIC STUDIES OF MULLERIAN MIMICS IN BUTTERFLIES OF THE GENUS HELICONIUS FIG. 7 FIG. 8 11 The Electroretinogram of Heliconius erato (Lepidoptera) and Its Possible Relation to Established Behavior Patterns1,2 S. L. SWIHART Department of Biology, Lehigh University Bethlehem, Pennsylvania (Plates I & II; Text-figures 1-6) [This paper is one of a series emanating from the William Beebe Tropical Research Station of the New York Zoological Society, at Simla, Arima Val- ley, Trinidad, West Indies. The station was founded in 1950 by the Zoological Society’s Department of Tropical Research, under Dr. Beebe’s direction. It comprises of 200 acres in the middle of the North- ern Range, which includes large stretches of govern- ment forest reserves. The altitude of the research area is 500 to 1,800 feet, and the annual rainfall is more than 100 inches. [For further ecological details of meteorology and biotic zones, see “Introduction to the Ecology of the Arima Valley, Trinidad, B.W.I.,” by William Beebe, Zoologica, 1952, 37 (13) 157-184. [The success of the present study is in large meas- ure due to the cooperation of the staff at Simla, espe- cially of Jocelyn Crane, Director, who contributed much of her knowledge of the organisms studied and helped with the recording of observations]. Introduction Numerous orders of insects such as the Odonata ( e.g ., Mazokin-Porshniakov, 1959) Orthoptera {e.g., Walther, 1958; Jahn & Wulff, 1942), Coleoptera (e.g., Jahn & Verner, 1941), Diptera (e.g., Autrum et. al., 1961) and Hymenoptera (e.g., Goldsmith, 1960), have been examined to determine the character of the insect electroretinogram. With the exception of Jahn & Crescitelli’s (1939) early work on the Cecropia moth, little, if any, electrophysiological data concerning the visual processes in the Lepidoptera have been obtained. This is particularly surprising in view of the fact Supported by a grant (NSF-G-21071) from the National Science Foundation. Contribution No. 1,043, Department of Tropical Research, New York Zoological Society. that their bright coloration, proved visual orien- tation (e.g., Crane, 1955; Ilse & Vaidya, 1956; Magnus, 1956) and rapid flight patterns all at- test to an acute visual system and well developed color discrimination. With these facts in mind, and as part of a continuing investigation into the biology of the heliconiine butterflies, this study into the character of the electroretinogram of Heliconius erato hydara Hewitson (1869) (see Kaye, 1921) was conducted. This species of butterfly common in the neo- tropics has already received careful attention from several viewpoints. Crane (1954) has de- scribed. the spectral reflection characteristics of its wing coloration in detail. Briefly, it is a small (2Vi" wing span), black butterfly, with brilliant scarlet patches on both the upper and lower sur- faces of the forewings. Its phylogenetic position is being established by Emsley as part of this over all study. Genetical studies of the described Trin- idad form, and the highly polymorphic forms found widely distributed over the South Ameri- can continent, are being studied by Emsley & Sheppard (e.g., Beebe, 1955). Crane (1955, 1957) has made a notable contribution in her studies of the behavior patterns and the role that visual orientation plays in the release of these patterns in this butterfly. These studies conclu- sively demonstrated its preference for the color orange as opposed to various shades of gray, and other hues, in their feeding behavior. On the other hand, red appears to play a major role in species identification and serves as a key ele- ment in the release of mating behavior. Other investigators, notably Eltringham (1933) and Ilse & Vaidya (1956), working with other species, have demonstrated visual orientation in butter- 155 156 Zoologica: New York Zoological Society [48: 11 fly feeding behavior. Magnus (1956) demon- strated that in certain butterflies, a cylinder with vertical colored and black bands, if rotated, would attract male butterflies. Increasing the speed of rotation increased the attractiveness of the cylinder. Several authors (e.g., Jahn, 1946; Crescitelli & Jahn, 1939) have discounted the existence of any color component within the electroretino- gram of insects. Recently Autrum (1960) has contested this viewpoint. Materials and Methods Butterflies used in these experiments were captured in the wild and maintained in large outdoor insectaries. This technique provided a ready source of healthy material. (See Crane & Fleming, 1953, for description of these cages). Since Heliconius erato settles quickly into a life within the insectaries, it was practicable to observe its behavior patterns and where neces- sary to record with high speed photography its wing beat frequency, etc. Electroretinograms were recorded using steel electrodes (tip diameter ca. 15 /x. Potentials were amplified with a Grass P-6 D.C. amplifier, presented on a Tektronix dual beam oscillo- scope, and recorded with Grass C-4 camera. The stimulus light source was a 100 watt, GE T8Vi/9 incandescent light (operated through a constant voltage transformer) with a color temperature of 2960°K. The light was focused into the ocular of a compound microscope, mounted horizontally inside a darkened and electrostatically shielded enclosure. A 16 mm. objective lens focused a spot (ca. .5 mm. di- ameter) of light upon the cornea of the specimen. Control of duration of stimulus was provided by a Compur type shutter and a rotating notched disk which could provide a flickering light source. Intensity was varied by means of a series of Bausch and Lomb neutral density filters. Mono- chromatic stimulation was accomplished by means of twelve “Balzers Liechtenstein” narrow- band interference filters covering the 420 m/x to 695 portion of the spectrum. Energy levels for each wavelength were com- puted on the basis of spectral emission curves provided by the lamp manufacturers, and the transmission curves of the interference filters (provided by Photovolt Corp.). Appropriate neutral density filters were then combined with each interference filter so as to obtain a nearly equal energy level at each wavelength. Absolute light intensity values were obtained using rather crude “grease-spot” photometric techniques and hence should be considered only approximate. In all recordings an upward beam deflection indicates a negative polarity of the active elec- rode. The electrophysiology laboratory was main- tained at a constant temperature of 68° F. Results The electroretinogram (ERG) of Heliconius erato quickly showed itself to be of a highly var- iable nature. It soon became apparent, however, that this variation could be fitted to a diurnal pat- tern. ERGs produced during the night hours, early morning and occasionally during the late afternoon, were found to be of one type. Another type of ERG was produced from mid-morning to some indefinite time late in the afternoon or evening. Plate I, fig. 1, shows selected results from an experiment which consisted of with- drawing a sample individual from the population within the insectary, every hour from 6 A.M. to midnight. It was found practicable to remove an individual from its “normal” environmental con- ditions and record the first ERG in only six to ten minutes. It will be noted that the individuals sampled at 0600, 0800, and 2400 presented an ERG quite different in waveform from that re- corded at 0900 and the remainder of the day. It is worth noting that the individual whose response is shown in 0800 altered the character of his response during the ensuing hour while mounted in the experimental set-up and by 0845 demon- strated a response quite like that illustrated in the figure for the organism sampled at 0900. The “night” response (e.g., 0600 wave form) can be characterized as follows: The initial response consists of a sharp rise in negativity, followed quickly by a very slight drop. This is followed by a sustained negativity which, upon intense stimulation, may show a slight, continual increase in magnitude (for stim- ulus durations up to 1 second) . Upon discontinu- ing the stimulation there may be a small irregu- lar-apnearing increase in negativity (or “off” re- sponse). The “day” response (i.e., 0900) can be de- scribed as often having a brief positive initial response (“A” wave), particularly upon stim- ulation with long wavelengths, followed im- mediately by the initial negative component or “B” wave which possesses a somewhat less steep- ly rising slope, and often contains a slight irreg- ularity. Following this depolarization there is a rapid repolarization which returns the recorded potential nearly to or below (positive) the resting potential. Then follows a sustained response or “C” wave which describes a gradually rising curve with a constantly decreasing slope. When stimu- lation is discontinued, a sudden increase in neg- ativity, or “D” wave, is observed. 1963] Swihart: Electroretinogram of Heliconius erato 157 In the course of these experiments well over a hundred individuals of H. erato have been sub- jected to ERG experimentation. All wave forms obtained in the course of these experiments can be described as either “day,” “night” or transi- tional. Plate I, fig. 2, illustrates a portion of a natural transition from “night” to “day.” In this instance the butterfly was removed from the in- sectary and “normal” environmental conditions just prior to 0800 and mounted in the darkened, temperature-controlled environment of the lab- oratory. The only light to which it was exposed was the actual test stimuli. Other experiments utilizing a comparable technique, when con- ducted at other times of the day, failed to reveal any comparable change in wave form. This tran- sition cannot, therefore, be attributed to dark adaptation, temperature effects, etc. It is extremely difficult to maintain these organ- isms for prolonged periods of time under artificial environmental conditions. I was successful, how- ever, in keeping three individuals alive for nearly three days in constant temperature (84° F.) and constant shadowless illumination (220 foot can- dles). At the end of this period the butterflies were sampled at 0800, 0830 and 1000 and dem- onstrated the “normal” transformation associ- ated with this time of day (Plate I, fig. 3) . On the basis of this experiment it is suggested that this transformation is regulated by a biological clock. Histological studies demonstrated that, as in Dytiscus (Jahn & Verner, 1941), retinal pigment distribution is not involved in the transition. In general it was observed that this transformation from “night” to “day” occurred very nearly simultaneously in all butterflies tested. That is to say, transition was occasionally observed to commence as early as 0745, but more commonly did not begin until about 0815. The transition was nearly always complete by 0900, but occa- sionally not until 0930. The other shift was not nearly so regular. Occasionally individuals were found to have returned to the “night” response by 1300. More commonly, however, this transi- tion did not take place until the very late evening and frequently was found to occur a consider- able time after the butterfly had gone to sleep for the night. Having thus established that the ERG consists of two superficially distinct wave forms; it be- came necessary to determine the characteristics of each type individually— the spectral response, flicker fusion frequency, variation in magni- tude with respect to stimulus intensity, etc. The “day” response is discussed first. Measurements of the magnitude of the initial negative or “B” wave component of the day re- sponse as a function of stimulus wave length produce the luminosity curve presented in Text- fig. 1. This curve shows a single peak at about 528 m/x, corresponding closely to the peak in spectral sensitivity obtained by Goldsmith (1960) for the worker honey bee. There is some indica- tion that there may indeed be a second peak in the ultraviolet. However, since equipment was not available for providing stimulation in this portion of the spectrum, no conclusions are presently possible. Analysis of the magnitude of the “D” wave or “off” response show that it normally bears a constant relationship to the magnitude of the “B” wave. Thus twelve “day” individuals were exposed to six different intensities of white light stimulation with relative strengths as follows: 1,4, 16, 64, 256 and 1,024. The average value for the magnitude of the “off” reponse, expressed as a fraction of “B” wave magnitude, were as follows: 28%, 33.5%, 31%, 32.5%, 25% and 27%, respectively. This variation of ± 4.2% is well within the range of experimental variation for the type of equipment and number of indi- viduals tested. If, on the other hand, the magnitude of the “off” response as a percentage of “B” wave mag- nitude is computed for the response to various wave lengths of equal energy, monochromatic stimulation, a marked deviation from a constant relationship becomes readily apparent. Thus, based on eleven individuals, the average magni- tude of the “off” response may vary from 19% of “B” wave magnitude up to a maximum of 46%. This represents a variation more than twice as great as the variation recorded in re- sponse to various white light stimulus intensities. Moreover, it will be noted that this variation expresses a fairly smooth, action spectrum, as indicated in Text-fig. 2, with a maximum at about 636 m/i. Obviously this action spectrum cannot be accounted for in terms of an intensity phenomenon, but rather indicates the respon- siveness of the “D” wave to the activity of some component with a spectral sensitivity basically different from the receptor responsible for pro- ducing the “B” wave. Various authors have maintained that the in- sect ERG does not show characteristics which are unique for the stimulus wave length. That is to say, all variations in the shape of the wave form can be attributed to an intensity phenome- non, and if proper stimulus intensities are chosen, so that the response to each wave length is of equal magnitude, then the wave forms become identical, regardless of the wave length of the stimulus. The triple recording in Plate I, fig. 4, demonstrates the response to stimulation with three widely separated wave lengths in which the 158 Zoologica: New York Zoological Society [48: 11 Text-fig. 1. Spectral response (luminosity) curves, based upon the responses of 14 individuals in the “night” phase, and 1 1 individuals in the “day” phase. Magnitude of B wave used as criterion. Since the absolute magnitude of electrical potentials recorded can vary considerably among individuals, the magnitude of each individual’s response to 12 wavelengths was measured as a percentage of the response to the wave- lengths eliciting the greatest response. These percentages were then averaged and plotted. intensities were adjusted so as to produce as nearly equal magnitude “B” waves as possible; it will be observed that each color presents a markedly different wave form. Also, it will be noted that this variation in wave form takes the form of a smooth series throughout the range of wave lengths tested and does not, in fact, show any tendency of the wave form to become identi- cal on either side of the “B” wave maximum of 528 mfx. It is, therefore, concluded that the “day” ERG possesses a distinct and unique component within the character of the wave form which may be attributed to stimulus wavelength alone. Other characteristics of general interest con- cerning the nature of the “day” visual response are presented in Text-figs. 3 & 4 and Plate II, fig. 5. Text-fig. 3 presents a dark adaptation curve based on the responses of three individuals. The technique involved in obtaining this curve was to focus a very intense white light upon the head of the butterfly for at least ten minutes. The light was then extinguished and the electrophysiologi- cal threshold (i.e., minimum stimulus intensity required to produce any electrical response) was determined after various time intervals in total darkness. This curve demonstrates the fairly rapid dark adaptation that takes place in H. erato. Text-fig. 4, is a typical flicker fusion versus stimulus intensity plot. As is usual, flicker fusion frequency is related to light intensity. A maxi- mum F.F.F. of 165 cycles/sec. has been re- corded, and characterizes the butterfly eye as moderately fast, certainly not the equal of the 250 cps Autrum (1958) recorded from the fly Calliphora, but, on the other hand, much faster than the 20 cps he reports for the grasshopper Tachycines. The response to a flickering light, however, shows a sustained negativity with the flicker responses superimposed. This type of response Autrum has characterized as typical of the “slow” eye. One other interesting phenom- enon is the fact that the response to a flickering light shows two critical frequencies (Plate II, fig. 5). The usual critical frequency or F.F.F. repre- sents the point at which the eye begins to respond discretely to each individual flash. These re- 1963] Swihart: Electroretinogram of Heliconius erato 159 Text-fig. 2. D wave magnitude as a function of stimulus wavelength. Each D wave was measured as a per- centage of the B wave magnitude elicited by the same 100 msec, test flash. The curve represents values obtained by averaging the responses of 11 “day” individuals. sponses can be shown to be “on” responses. At some other much lower frequency (20-26 cps) it can be demonstrated that another significant phenomenon takes place. This is in essence a transition from “on” to “off” responses. As for the night response, Text-fig. 1 presents a luminosity curve derived from the magnitude of the initial negative wave. It is apparent that this action spectrum has two maxima. One is identical with that of the “day” response (528 m/x) but another new maximum develops at 616 m^u with a plateau connecting these two peaks. It is worth noting that this new peak in the red corresponds approximately to the peak in the luminosity curve derived from the “D” wave of the “day” response (Text-fig. 2). No satisfactory “D” wave luminosity curve can be computed for the “night” response because of the small and irregular nature of this component. It is, how- ever, worth noting that the maximum F.F.F. observed in an eye producing the night response was 90 cycles per second and that no second critical frequency is observed. The response characteristic of night, quite un- like the “day” response, does not have a color component apparent in the wave form. Plate II, fig. 6, shows the response to the same three wave lengths as utilized in Plate I, fig. 4. It will be noted that it is possible to cause the wave form obtained from any wavelength within the visual spectrum to coincide with the wave form produced by any other wavelength. Text-fig. 5 contrasts the increase in response magnitude accompanying an increase in stimulus magnitude in both “day” and “night” responses. A given increase in stimulus intensity produces a greater increase in electrical response in the “night” eye than in the “day” eye. No statistically significant difference between dark - adapted thresholds of “day” and “night” eyes could be detected. In conjunction with these electrophysiological experiments, certain observations upon normal behavior patterns were conducted. Text-fig. 6 demonstrates graphically the results of these observations made upon the frequency of certain types of activity throughout one day. Environ- mental conditions (/.?., light and temperature) 160 Zoologica: New York Zoological Society [48: 11 Text-fig. 3. Dark adaptation curve based upon the responses of three individuals in the “day” phase. Figures were obtained by determining the minimum stimulus intensity necessary to produce a threshold electrical response, after various periods in total darkness. Eyes were light-adapted for at least 10 minutes before testing. Sensitivity did not increase after about 10 minutes’ dark-adaptation, even after periods in darkness in excess of one hour. were also observed. The activity of the butterflies was measured on the basis of the number of in- dividuals within the sample population in flight at any given instant. The points on this curve represent the average of four such counts at fifteen-minute intervals. Since all the females in the insectary were pre- sumably mated, no actual mating took place during the observation period. Crane (1957) discussed, however, the irrelevant courting pro- cedure as observed in H. erato. Male butterflies will frequently attempt to court mated females and will demonstrate not only the typical chase patterns, but also the usual courtship “fanning” activity until rejected by the female. The number of such courtships was taken as an index of sex- ual activity. The individuals within the insectary were observed continuously and each attempted courtship was recorded as belonging to one of two categories: (1) probable courtships, in which the interaction between individuals was either brief or not of a typical nature; (2) confirmed courtship attempts, which were prolonged and demonstrated several phases of the typical court- ship pattern. The bar graph in Text-fig. 6 indicates the num- ber of courtship attempts of both categories per half hour interval of time. By filming some of these courtship attempts at 64 frames per second, it was possible to ac- curately determine the frequency of the wing beat during fanning activity. This was found to be remarkably constant and was at a frequency of 13 cycles or 26 wing strokes per second. Conclusion Based upon the foregoing, it seems clear that the ERG as recorded in the “day” phase and that recorded in the “night” reflect fundamentally different visual processes. It would appear that the “night” response is in essence a generalized photic response in which certain types of inform- ation have been sacrificed in order to attain maxi- mum responsiveness to a minimum change in stimulus intensity. Because of the two maxima presented by the “night” luminosity curve, it 1963] Swihart: Electroretinogram of Heliconius erato 161 Text-fig. 4. Flicker Fusion Frequency (F.F.F.) as a function of white-light stimulus intensity. Response of a fairly typical individual in “day” phase. Relative stimulus intensity of 1,000 equal to about 75,000 micro-watts in the 400 nqi to 700 mp, portion of the spectrum. would seem logical to presume that several pig- ments (or receptors) are involved in producing the initial response. The “day” response, on the other hand, ap- pears to have a well defined ability for resolving the spectral characteristics of the stimulus. The different luminosity curves obtained from “B” and “O” waves of the “day” response would indicate that several receptors are being utilized, each producing different components of the ERG, and that the differential responses charac- teristic of these components are being integrated in such a manner as to produce color informa- tion at the expense of some photo-sensitivity. The curves presented in Text-fig. 6 indicate quite clearly that the courtship behavior of H. erato is not related temporally to the flight ac- tivity or to such environmental conditions as light or temperature; that is to say, the maximum courtship efforts do not, in fact, come simul- taneously with the maximum flight activity or with a maximum of light or temperature. We must therefore look in other directions to deter- mine what factors control the time of courtship activity. Attention is directed to the close similarity between the 20-26 cycle per second frequency at which the “day” response to a flickering light becomes an “off” response, and the 26 stroke per second frequency characteristic of courtship wing flutter. Summary The experimental work suggests an intimate and fundamental correlation between the ob- served electrical phenomena and basic behavior patterns. It would appear that at some critical time during the day a biological clock mecha- nism alters the visual mechanism in such a way that the butterfly is now prepared to receive the sensory information required in releasing the innate courtship behavior. Thus, in the morning it rather suddenly gains an “awareness” of color and an increased ability to perceive rapidly mov- ing (fluttering) objects. With the transition to the “night” phase, its ability to respond to court- ship releasers disappears. The wide variation between individuals in the time of this second transition may perhaps be related to the individ- ual’s physiological state— whether it is young or old, mated or unmated, etc. Further experiments 162 Zoologica: New York Zoological Society [48: 11 Text-fig. 5. Relationship between white-light stimulus intensity and magnitude of B wave electrical response, with the response to the weakest stimulus used, arbitrarily set at 1. Each curve represents the values obtained by averaging the responses of 1 1 individuals. A relative stimulus intensity of 1,000 is equal to about 75,000 micro-watts in the 400 mp, to 700 mp portion of the spectrum. are planned to elucidate any possible relationship of this nature. It is indeed quite attractive to speculate that this “clock” mechanism may regulate much more than just visual processes. Alexander (1961) reports that “before 9:00 A.M.” is the most com- mon time for emergence of the adult from the pupal form. She also gives this same period of time (0800 to 1030 )as the usual time of shed- ding the last larval skin (pupation) . Various workers ( e.g ., Autrum & Gallwitz, 1951) have concluded that the “off” response is an inhibitory nervous component and that it sup- presses the activity of the primary receptors. I agree with this point of view and will demon- strate in a forthcoming paper that the initial negative response, characteristic of the “day” eye, contains an excitatory nervous component which effectively increases the magnitude of the response of the eye to any given stimulus. With these facts in mind, it becomes quite clear that the transition from “on” to “off” responses characteristic of the response to various flicker frequencies is an extremely significant neurologi- cal phenomenon. This, in essence, constitutes the transition between increased responsiveness and decreased responsiveness as compared with the magnitude of the response elicited by the pri- mary receptors. Magnus’s observations concerning the respon- siveness of male butterflies to certain frequencies of colored flickering light indicate that flicker rates play a role in species recognition. The cor- relation between the wing beat frequency and the transition to increased photic stimulation appears to be too close for mere accident. It may indeed be that the fluttering activity associated with courtship behavior serves, in part, as a visual releaser for the final phases of courtship activity. It is expected that further research into the sensory electrophysiology of the heliconiine butterflies will provide further positive correla- tions between their complex behavior patterns and basic neuro-physiological mechanisms. References Alexander, A. J. 1961. A study of the biology and behavior of the caterpillars, pupae and emerging butter- 1963] Swihart: Electroretinogram of Heliconius erato 163 Text-fig. 6. Plot of courtship behavior, flight activity, and environmental conditions, based upon observa- tions of ca. 50 individuals within a large outdoor insectary, throughout one day. The bar graph represents courtship activity (see text), hatched bars depict positive courtship attempts, while unshaded bars represent questionable, or brief, attempts. Height of bars equal to total number of attempts per half hour period of time. Light intensity is incident light in open shade as measured with a Weston model 756 illumination meter. The flight activity is based upon the total number of individuals in flight at a given instant. Light intensity, air temperature and flight activity were measured at 15-minute intervals, four such determinations were averaged, and hourly figures plotted. The peak of flight activity at 1830 is due to the social roosting behavior of H. erato. flies of the subfamily Heliconiinae in Trini- dad, West Indies, Part II. Moulting, and the behavior of pupae and emerging adults. Zoologica, 46: 105-124. Autrum, H. 1958. Electrophysiological analysis of the visual system in insects. Exp. Cell Res. Suppl., 5: 426-439. 1960. In: “Mechanisms of Color Discrimina- tion,” Pergamon Press, London, pp. 32-39. Autrum, H„ I. Autrum & C. Hoffmann 1961. Komponenten im Retinogramm von Calli- phora und abhangigkeit von der Spektral- farbe. Biol. Zentral., Band 80, Heft 5: 513-547. Autrum, H„ & U. Gallwitz 1951. Zur Analyse der Belichtungspotentiale des Insektenauges. Zeitschr. Vergl. Physiol., 33: 407-435. Beebe, W. 1955. Polymorphism in reared broods of Heli- conius butterflies from Surinam and Trini- dad. Zoologica, 40: 139-143. Crescitelli, F., & T. L. Jahn 1939. The electrical response of the dark- adapted grasshopper eye to various inten- sities of illumination and to different quali- ties of light. Jour. Cell, and Comp. Phy- siol., 13 (1): 105-112. Crane, I. 1954. Spectral reflectance characteristics of but- terflies (Lepidoptera) from Trinidad, B.W.I. Zoologica, 39: 84-115. 1955. Imaginal behavior of a Trinidad butter- fly. Heliconius erato hydara Hewitson, with special reference to the social use of color. Zoologica, 40: 167-196. 1957. Imaginal behavior in butterflies of the family Heliconiidae: changing social pat- terns and irrelevant actions. Zoologica, 42 : 135-145. Crane, J., & H. Fleming 1953. Construction and operation of butterfly insectaries in the tropics. Zoologica, 38: 161-172. 164 Zoologica: New York Zoological Society [48: 11 Eltringham, H. 1933. The Senses of Insects. Methuen, London, ix + 126 pp. Goldsmith, T. H. 1960. The nature of the retinal action potential and the spectral sensitivities of ultra-violet and green receptor systems of the com- pound eye of the worker honeybee. Jour. Gen. Physiol., 43: 775-799. ILSE, D., & V. VAEDYA 1956. Spontaneous feeding response to colors in Papilio demoleus L. Proc. Ind. Acad. Sci., 43 B: 23-31. Jahn, T. L. 1946. The electroretinogram as a measure of wavelength sensitivity. Jour. New York Ent. Soc., 54: 1-8. Jahn, T. L., & F. Crescitelli 1939. The electrical response of the Cecropia moth eye. Jour. Cell, and Comp. Physiol., 13 (1): 113-119. Jahn, T. L„ & J. W. Verner 1941. Retinal pigment distribution in relation to a diurnal rhythm in the compound eye of Dytiscus. Proc. Soc. Exp. Biol, and Med., 48 (3): 656-660. Jahn, T. L., & V. J. Wulff 1942. Allocation of electrical responses from the compound eye of grasshoppers. Jour. Gen. Physiol., 26 (1) 75-88. Kaye, W. J. 1921. A catalogue of the Trinidad Lepidoptera, Rhopalocera (butterflies). Mem. Dept, of Agriculture, Trinidad and Tobago, No. 2, xii -f- 163 pp. Magnus, D. B. 1956. Experimental analysis of some “overopti- mal” sign-stimuli in the mating-behaviour of the fritillary butterfly Argynnis paphia L. (Lepidoptera: Nymphalidae). Proc. Tenth Inter. Cong, of Ent., 2: 405-418. Mazokin-Porshniakov, G. A. 1959. Colorimetric study of vision in the dragon fly. Biophysics, 4: 46-57. Walther, J. B. 1958. Changes induced in spectral sensitivity and form of retinal action potential of the cockroach eye by selective adaption. J. Ins. Physiol., 2: 142-151. 1963] Swihart: Electroretinogram of Heliconius erato 165 EXPLANATION OF THE PLATES Plate I Fig. 1. Selected ERGs recorded with 15/x sub- corneal, steel electrode; D.C. amplifica- tion. Such records were made at hourly intervals throughout the day from individ- uals removed from the large insectaries. The 0600, 0800 and 2400 responses are typically “night” in character. The other records are “day”-type responses. Lower trace indicates period of stimulation ( 100 msec). A similar recording technique was employed in producing the ERGs pre- sented in subsequent figures. Fig. 2. Three recordings from one individual, demonstrating the changing response to white light at different times of the day (0800, 0900 and 0930). The butterfly was maintained in total darkness (except for 100 msec test flashes, at 15 minute inter- vals) and constant temperature, 68° F. The first recordings (0800) is clearly transitional in nature. The 0900 recording illustrates the development of the “dip,” i.e., return to, or below, the baseline, fol- lowing the B wave. Also shown is the de- velopment of a C wave instead of a nearly constant, sustained negativity. The last ERG demonstrates the development of a pronounced “off” effect, and is a “typical” day response. Fig. 3. ERG responses of three individuals to white-light stimulation of 100 msec, dura- tion, after being maintained under con- stant environmental conditions of 220 ft-c shadowless illumination and 84° F. for various periods of time before subjecting to experimentation. The individual sam- pled at 0800 was so maintained for 65 hours, the 0830 for 46.5 hours, and the 1000 individual for 67 hours. In spite of deprivation of normal environmental stimuli, these butterflies demonstrate a typical diurnal pattern, with the one tested at 0800 producing a “night” response; the 0830, a transitional, and the 1000 a “day” response. Fig. 4. Superimposed ERGs from an individual producing a day response, to three dif- ferent wavelengths (616 mp,, 528 mp, and 420 mp) with stimulus intensities adjusted to produce nearly equal magnitude B wave responses. Relative stimulus energies were 4:1:1 respectively. Stimulus duration 100 msec. The response to red demonstrates the greatest “dip” following the B wave (fall- ing below the lower trace) and the largest D wave or “off” effect. The blue stimulus (420 mg), produced the smallest dip and D wave. Blue-Green (528 mg) elicited a response intermediate in both respects. Plate II Fig. 5. Four selected one second portions from one continuous recording of the response of a “day” eye to flickering white light. Stimulus energy about 20,000 micro-watts, in the 400 to 700 mg portion of the spec- trum. Flicker was produced by a rotating, sec- tored disk, with a gradually decreasing rotational velocity. Periods of darkness are equal to periods of stimulation. Flicker frequency was monitored by a photo-cell (lower trace). Elevated portions of the lower trace indicate periods of stimulation. Portion A of recording: The initial re- sponse to a rapid flicker ( 140 cps) is iden- tical to the day response to steady illumi- nation. The gradual decline in the level of the base line is due to the use of a 1 cps filter. B: Illustrates the F.F.F. or development of discrete electrical responses to each in- dividual flash, at 1 10 cps. C: Illustrates the development of an “off” response. On the left side of the fig- ure, the beginning of the electrical re- sponse coincides with the beginning of stimulation, while toward the right, at about 25 cps, a second component begins to develop, which causes the electrical re- sponse to preceed the stimulus. D: Illustrates how this second compo- nent gradually increases in importance until the response becomes entirely “off” in nature. Fig. 6. Superimposed ERGs from an individual producing a night response, to the same three wavelengths used for Fig. 4 (616 m/x, 528 my, and 420 m /x ) . Stimulus duration 100 msec. Intensities adjusted to produce nearly equal magnitude initial negative responses. Relative stimulus intensities 2:1:2, respectively. Waveforms elicited are essentially identical. SWIHART PLATE 1 0800 0900 0930 FIG. 2 FIG. 4 THE ELECTRORETINOGRAM OF HELICONIUS ERATO (LEP1 DOPTERA) AND ITS POSSIBLE RELATION TO ESTABLISHED BEHAVIOR PATTERNS SW1HART PLATE 1 1 PORTION A B C D 1 mV 1,4’ FIG. 5 FIG. 6 THE ELECTRORETINOGRAM OF HELICONIUS ERATO (LEPIDOPTERA) AND ITS POSSIBLE RELATION TO ESTABLISHED BEHAVIOR PATTERNS 12 The Display of the Blue-backed Manakin, Chiroxiphia pareola, in Tobago, W.L1’2 D. W. Snow Department of Tropical Research, New York Zoological Society, Bronx 60, N. Y. (Plates I-III, Text-figures 1-3) [This paper is one of a series emanating from the Tropical Field Station of the New York Zoological Society, at Simla, Arima Valley, Trinidad, West Indies. This Station was founded in 1950 by the Zoo- logical Society’s Department of Tropical Research, under the direction of Dr. William Beebe. It com- prises 200 acres in the middle of the Northern Range, which includes large stretches of undisturbed government forest preserves. The laboratory of the Station is intended for research in tropical ecology and in animal behavior. The altitude of the research area is 500 to 1,800 feet, and the annual rainfall is more than 100 inches. [For further ecological details of meteorology and biotic zones, see “Introduction to the Ecology of the Arima Valley, Trinidad, B.W.I.,” William Beebe, Zoologica, 1952, 37 (13): 157-184.] There have recently been several contribu- tions to our knowledge of the extraordi- nary joint displays of manakins of the genus Chiroxiphia. Something is now known of all four species. Wagner (1945) and Slud (1959) have reported on C. linearis; Lamm (1948), Snow (1956), Junge & Mees (1958), Gilliard (1959) and Sick (1959) on C. pareola; Friedmann & Smith (1955) briefly on C. lan- ceolata; and Sick (1942 and 1959) on C. caudata. C. linearis, C. lanceolata and C. par- eola are closely related, allopatric forms, to- gether comprising a super-species, while C. cau- data is more distinct and its range overlaps that of C. pareola. Correspondingly, the first three have rather similar displays, while that of C. caudata is more distinct. In the first three species, Contribution No. 1,044, Department of Tropical Re- search, New York Zoological Society. 2This study has been supported by National Science Foundation Grants G 4385 and G 21007. pairs of males perform a synchronized dance, alternately jumping up and uttering while in the air a vibrant, growling note; whereas in C. cau- data several males engage in a joint dance, the details of which, though the published accounts are discrepant, appear to differ considerably from anything found in the other three species. For the Blue-backed Manakin of Tobago, C. pareola atlantica, which forms the subject of the present paper, Gilliard’s observations have added significantly to my earlier account, and I myself have returned three times to Tobago to watch and film their displays and record their calls. The accounts by Lamm and Sick of the display of the northeast Brazilian population (subspe- cies pareola), brief though they are, indicate that their display does not differ in important respects from that of the Tobago population. Nothing is known of the displays of the pop- ulations of the interior of South America (sub- species napensis, regina and boliviano. Chiroxiphia pareola is one of the largest of the manakins, and atlantica is the largest of its subspecies; adult males weigh from 20 to 25 gm. The adult male is black, with a flat red “skull- cap” somewhat triangular in shape with two backwardly projecting lateral horns, and a sky- blue patch on the upper back (Text-fig. 1). The legs are pale orange. The female is olive-green. Young males are green, but by the age when they begin to visit the display perches they show a certain amount of red on the crown and some- times some blue on the back. The genus Chir- oxiphia is characterized by the specialized outer- most primaries. In the male only, the three outer primaries are pointed, the shafts being thickened and the barbs reduced. It is, however, not clear 167 168 Zoologica: New York Zoological Society [48: 12 Text-Fig. 1. Adult male Blue-backed Manakin, uttering the invitation call. (Drawn from movie film.) in what way, if any, these specialized feathers are used in the displays. The only undoubted me- chanical noise, a soft click made on taking off, could hardly be made by them. It may be that the slotted wing-tip is aerodynamically import- ant in the fluttering jumps that are the most important element in the display. Slud’s admirably clear account of the song and dance of the Central American C. linearis has shown how conflicting may be the different published accounts of the display of the same species of manakin. This has been partly due, no doubt, to inaccurate observation of complex and often rather quick movements, and espe- cially in the older accounts, to reliance on mem- ory rather than on detailed notes made at the time. Partly it results from the different observers having seen different fragments of a complex and varied pattern of display, complex in that many different display movements and postures are involved, varied in that the organization of a display sequence depends much on the circum- stances and status of the individuals taking part. For C. pareola in Tobago there is, compared with C. linearis, a notable absence of conflicting observations, though much remains to be done to clarify the social relationships of the display- ing birds. The display appears variable, and is so, but this variability is in the arrangement and coordination of display elements which are them- selves highly stereotyped. A movie camera is ex- tremely valuable for providing an accurate por- trayal of these postures and movements, and a tape recorder for providing an objective trans- cription of the sounds accompanying them. These I have attempted to present in the follow- ing pages. As usual, I am most grateful to my wife for help with the field work, especially in the tape- recording and in maintaining longer watches at the display perches than would have otherwise been possible. I wish to thank Professor P. P. Kellogg, Dr. R. C. Stein and Mr. C. A. Suther- land, of the Laboratory of Ornithology, Cornell University, for their help and advice, and Mr. Sutherland especially for making the sonagrams. I also acknowledge with gratitude grants from the National Science Foundation. The Display Perches Blue-backed Manakins display on bare sticks or stems in the forest undergrowth, usually two to five feet above the ground. Display perches may be sloping or horizontal, straight or curved, but most of those seen were slightly sloping and convexly bowed. Sometimes a small group or cluster of perches is used. Between bouts of displays the birds peck at the bark, which they also wear smooth with their continual perching and hopping, and they pick in flight at the leaves surrounding the perch. When they have pulled off a piece of leaf, they typically re- turn to the display perch before dropping it. In April, 1959, the same display perches were found to be in use as had been used in July, 1958, in forest near the top of Pigeon Peak. Also a display perch which was watched in April, 1959, in secondary forest nearer the coast was still in use in July, 1961. This was the area which Gilliard had watched, and where he was told that manakins had been dancing for decades. Thus there is little doubt that the dis- play grounds are permanent, and that the same display perches normally remain in use as long as the surrounding vegetation is unchanged and the perches themselves remain suitable. Gilliard suggests that the primary function of the clearing of leaves from the vicinity of the display perch may be defensive, in preventing the close approach of unobserved predators. He further suggests that it may have value in in- creasing the amount of sunlight penetrating to the perches and so enhancing the effect of the bright red and blue of the male’s plumage. The clearing of obstructions from the area of a dis- play perch or court is probably widespread in manakins, being known also in Manacus and three species of Pipra (Snow, 1962, a and b) ; in the related Cotingidae it occurs in the much larger Calfbird Perissocephalus tricolor, which has its display perches in the canopy of forest trees (B. K. Snow, 1961). The evidence strongly suggests that the habit of spending hours in conspicuous display does not in fact expose man- akins to heavy predation; for M. manacus, the annual mortality of adult males was found to be only 11%, an exceptionally low figure for a small passerine bird (Snow, 1962 a), and the mortality of Pipra erythrocephala seemed to be 1963] Snow: Display of Blue-backed Manakin 169 similar (Snow, 1962 b). I suggest that the pri- mary function of leaf-clearing in all these spe- cies is to keep the display perch or court clear of the growing vegetation, so that the site re- mains permanently suitable for display. A fur- ther advantage is that such places will be more conspicuous than if they were screened by the surrounding vegetation. Secondarily, as Gilliard suggests, such stripping of the vegetation may, by allowing more light to penetrate, enhance the colors of the displaying bird. Calls and Mechanical Sounds Invitation Calls Three calls may conveniently be grouped un- der this heading, in that they are uttered by males sitting by themselves, and appear to serve as invitations to neighboring males to join them in display, or perhaps in one case, to females to do likewise. Rigorous examination of their functions was not possible under the conditions of observation. The chief of these calls is a rolling churr, “chrrrrr,” often followed by one, two or occa- sionally three abrupt, rather explosive notes sounding like “chup” (Plate I, fig. 1). Typically, this call is uttered by a solitary male perched 20 or 30 feet up in the area of a display perch, and it seems very clearly to be used to attract another male to come and call with it in unison (see next section). Though they are often uttered in se- quence, either the “chrrrrr” or the “chup” may be uttered by itself; in such cases single “chups” may be repeated at the rate of up to 20 per minute, and the rolling churr at rather longer in- tervals. (Gilliard describes this call as a “wren- like ‘wwwwrrr’, drawn out and ascending, and ending with an explosive ‘churr’ or ‘chow’, which was sometimes twice repeated”) . The second invitation call is a single “whee” or double “whee, whew” (using Gilliard’s phras- ing), the first note being sharp and incisive and the second less loud and lower-pitched (Plate I, fig. 3). This call is uttered by males perched by themselves, not usually on the main calling perches, but between flights from one perch to another round the display area. Anthropomor- phically, it seems to indicate restlessness and the desire to attract another bird. A much less common call than those just de- scribed (and for this reason unfortunately not recorded on tape) was a double “coo-ee” or “joy- ee,” the first note low and musical and the second sharper. (This call is described by Gilliard as “chew- wheat”). Gilliard refers to it as an invi- tation call, and the first call of the day. My notes suggested that it was sometimes associated with the presence of a female, especially in one case where a male uttered it continually, and no other call, for several minutes near a display perch after a female had appeared near by. But it was heard too seldom for any safe generaliza- tion. Synchronized Calling When, after calling the “chrrrrr-chup,” a male has been joined by another, both perch close together, sometimes side by side and near- ly touching, and utter a series of perfectly syn- chronized ringing phrases, sometimes for min- utes on end. Each phrase consists of one to five “chups” quickly repeated (Plate I, fig. 2), three being the commonest number, and the phrases themselves are repeated at the rate of 30 to 45 per minute. In the course of each bout of syn- chronized calling there is a tendency for the length of the phrases to increase, as shown in the following count of phrase-length in a complete bout of calling, divided into three periods : Number of phrases 1 st 2nd 3rd period period period Number of “chups” 5 — — 1 per phrase 4 — 23 3 6 11 2 2 7 4 - 1 1 - - I watched pairs of males calling thus on many occasions and was always struck by the ap- parently perfect synchronization of the opening and closing of their beaks, which was the more striking as the intervals between each phrase varied somewhat and each phrase, as already mentioned, might consist of one to five notes. In fact, the sonagram shows that one bird called about 0.04 or 0.05 seconds later than the other. It is especially interesting that slight individual differences in the form of the “chup” note show that the bird which called first was the one that had previously been recorded giving the invita- tion call (the “chrrrr-chup”) above the display perch. On one occasion two birds came together, but began to call when they were still several yards apart and continued to do so for some time. At this unusual distance their calls were very poorly synchronized, indicating that synchronization depends on one of the birds being able to detect slight intention movements in his partner. Once only, three birds were seen calling together, when two adult males were perched close to- gether calling synchronously and an immature male joined them, perched about two feet away, 170 Zoologica: New York Zoological Society [48: 12 and called for some time in unison with them. (Gilliard aptly described this call as a “resound- ing phrase that rang through the forest like the clicking of billiard balls,” but does not mention that it is the synchronized call of two birds) . When one watches a single bird uttering his invitation call over and over again, the rolling churr followed by usually a single “chup,” and it is then joined by another male, whereupon both break into a resounding series of “chup- chup-chups,” one receives the strong impression that the solitary male is eager to utter the longer, louder phrases, but simply cannot do it without the cooperation of another bird. Frequently, after a bout of synchronized calling, both birds fly down to the display perch and begin a bout of jumping. The synchronized calling thus prob- ably plays some part in building up the motiva- tion for the joint display. Two Blue-backed Manakins sitting side by side remind one of Pipra and Manacus, in which males with neighboring display perches or courts spend long periods sitting beside each other on some perch mid-way between, but there are im- portant differences. First, Blue-backed Mana- kins come together to call in unison; when the bout of calling is over they part. Males of Pipra and Manacus on the other hand perform no joint activity, but simply come together between bouts of display. Secondly, whereas in Pipra and Manacus such birds, though drawn together, are still plainly antagonistic towards each other, and in Pipra especially they always face away from one another, in the Blue-backed Manakin they show no mutual hostility; they face each other freely, and if one turns on the perch it may turn towards the other. There seems to be no remnant of aggressiveness in their behavior on the calling perches. Calls and Mechanical Sounds Associated with the Display The jumping display which will be described in detail in the next section is accompanied by a vibrant twanging or buzzing call (Plate II, fig. 4) . It is uttered by the bird as it hangs in the air with beak open and head pointing downward (Text-fig. 2). When, as is usually the case, two males jump up alternately, these vibrant calls succeed one another at regular intervals, and carrying surprisingly far for their volume, they are the chief means by which the observer lo- cates the display perches. As the display pro- ceeds and the jumps become smaller and more rapid, the calls, which start as rather smooth, regularly alternating buzzing notes, become more irregular and take on a bleating quality (Plate TT, figs. 5 & 6). As Gilliard puts it, they Text-Fig. 2. A pair of male Blue-backed Manakins performing the cartwheel dance; one bird hovering and uttering the twanging call, the other shuffling up the perch in a crouched position. (Drawn from movie film.) become “very irregular and forced, as though they were purely mechanical sounds coming from a wavering toy top.” It seems as if, though vocal, they are also to some extent mechanical, in that they are gradually modified by the physi- cal exertion of the fluttering jump, and this im- pression seems to be supported by the fact that the smoother buzzing note, characteristic of the early stages of the jumping display, is sometimes uttered in typical form by a perched bird. At the end of a bout of jumping, after the twanging calls have speeded up to the rapid and confused buzzing mentioned above, the display usually ends with a sudden and rather startling vocal performance. The last bird to jump utters a louder and more distinct bleating note, with the beak wide open, and this is at once followed by a quite different, higher-pitched “zeek” or “zeek-eek,” repeated up to four or five times, after which the two birds at once fly off from the display perch. I was unable to tell whether one or both of the birds uttered these sharp calls, but 1963] Snow: Display of Blue-backed Manakin 171 a single bird jumping by itself will often end its display with exactly the same sequence of calls. That the sharp “zeek-eek” not only brings this display sequence to an end, but actually acts as an inhibitor of display, was once very clearly seen, when an adult male performed the pre- copulatory display, described later, to an im- mature male, which some of the time behaved like a female and some of the time joined the male in joint display. Four times in the course of this joint display the immature male suddenly uttered the sharp “zeek-eek,” and each time, though the activity of the birds was not the same on each occasion, it was followed by a break of several seconds before the two birds resumed their display. During the precopulatory display described in a later section, a note was uttered that was heard at no other time. This was a low twanging note, which may be written “quaaaa”, uttered by the male before flying in to his display perch from another perch a few yards away. It was a call of low volume and was not registered by the tape recorder at a distance of about 25 feet. When flying to and from their display perch, and sometimes when flying about near it, males may sometimes make a soft mechanical click at the moment of taking off (Plate III, fig. 7). The male which continually uttered the “coo-ee” call for several minutes after a female had appeared near his display perch, also made the click every time he flew, and during the precopulatory dis- play it was made by the male when he flew in to his display perch, after uttering the twanging “quaaaa”. The click is almost certainly made by the wing-feathers, but the way in which it is produced was not discovered. The narrow and rigid outer primaries do not seem to be adapted to make such a sound; in Manacus the special- ized secondaries are responsible for the loud snap made on taking off. The Jumping Display The fluttering jump is the basic movement of this display. Before jumping, the bird crouches a little. It then jumps up with fluttering wings, the beak pointing downwards, legs dangling, and tail pointing down (Text-fig. 2), and hangs mo- mentarily in the air before landing back on the perch. The jump may occasionally be silent, but is normally accompanied by the twanging call, the beak being opened widely. As already mentioned, in C. pareola as in its two close relatives, the jumping display is typi- cally performed by pairs of males, which jump alternately on the same perch. When the first one jumps, the other crouches, looking upwards at it, and then itself jumps as the first bird lands. But single males may jump, though they do not usually keep up the display for very long. When a male jumps by itself, at every jump it turns in the air so as to land facing the other way on the perch. When two males jump together their movements usually become more complex and the turn in mid-air is less obvious or is altogether suppressed by the requirements of their coordi- nated dance. When two males dance together, in the sim- plest form of the display they jump up alter- nately side by side, each keeping his place on the perch unaltered. But sometimes the display is less regular, and they may jump more at random to land in another place on the same perch or on another perch a foot or two away. Sometimes one bird jumps over the other. Even when the jumping is at its least orderly, the two birds jump in strict alternation. Exceptionally, three birds may jump on the same perch, but their behavior apparently does not allow coordinated dancing by more than two birds. On the only occasion when this was seen, two of the birds jumped up alternately, while the third jumped at a little distance along the perch, out of phase with them. The jumping of two males reaches its highest pitch of coordination when a third bird (a fe- male, or a juvenile male who assumes the role of the female; see later) comes to the perch. The two males then turn and face the third bird, and the following sequence of display develops. The foremost of the two males jumps up, and as it hovers in mid-air the other male hops up to take its place. The first bird moves back in flight and comes down to land, and as it lands the other jumps up in the same way. Thus the two males move in the form of a Catherine wheel, or cart- wheel (Gilliard), before the third bird. If, as sometimes happens, the third bird retreats, back- ing away up the perch, the males hop up further when on the perch and do not move back so much in flight, so that the cartwheeling pair move up the perch after the retreating bird. If, as was also seen, the third bird is aggressive and moves towards the pair, they retreat, still cart- wheeling. The cartwheeling display appears to be best performed on a sloping perch, with the two males facing “uphill,” but it may also be performed on nearly horizontal perches. If the third bird flies off to another perch a few feet away, the pair of cartwheeling males may follow and continue jumping in front of it; but if it moves further off they do not follow but either stop jumping or return and continue jumping on the main perch. Cartwheeling displays were seen many times. 172 Zoological New York Zoological Society [48: 12 On some occasions the third bird was thought to be a female, having all-green plumage, and sometimes it was an immature male, with some red feathers in the crown. In the precopulatory display, too, as described in the following sec- tion, the female’s role may be taken by an im- mature male. Sick (1942) found the same in Chiroxiphia caudata. All bouts of jumping, whether by single males, pairs of males by themselves, or pairs of males before a third bird, usually become faster and more frenzied as they proceed. The jumps become lower and succeed one another more rapidly, until the birds are hardly leaving the perch and the alternate rhythmic twanging degenerates in- to “unintelligible buzzy sounds,” a phrase used by Slud for C. linearis and equally applicable to the Tobago bird. The last jump of all is often especially frenzied; the bird turns its body rap- idly from side to side as it flutters, and as already mentioned, utters a rather loud bleating call with beak wide open. Then the sudden sharp notes are uttered, and at the same instant the jumping stops and the birds usually fly off. The Precopulatory Display On March 30 and 31, 1959, a long sequence of display was seen between an adult male and a female, which on March 31 culminated in copulation six times. This display was stereo- typed and extremely different from the jumping display described above. It began when the female suddenly appeared on the display perch. The male then proceeded to flutter round her with a butterfly-like floating flight, crossing and re-crossing the display perch, every second or so alighting momentarily on a perch and flying on again with a buoyant, bouncing motion. In flight his wings were kept well extended and appeared to move with rapid, shallow beats, and his beak was open, though no sound was uttered. If he alighted on the dis- play perch or some other perch near the female, he would face her, crouch for a moment with head lowered, so that the blue patch on the back was exhibited, and vibrate his wings. As his head came down, the red cap was presented squarely to the female, appearing shield-like as the two horns were extended laterally, apparently by muscular action (Text-fig. 3). The female was thus presented with a red shield surrounded by black and surmounted by a vibrating patch of sky-blue. Sometimes when the male stopped in the course of his bouncing flights and faced the female, he did not adopt this posture but merely crouched, with wings flicking. Several times in the course of this display, and on both days, the male flew out to a special perch some 20 feet from the display perch, in a direction in which he did not otherwise go, uttered a low twanging note on the perch (the “quaaaa” described above), then with a click of the wings flew back to the display perch and resumed his bouncing flight. Text-Fig. 3. The precopulatory display. The male crouched, between two fluttering jumps, and exhibiting his red crown shield to the female; the female, on the main dis- play perch, intently watching the male’s performance. (Drawn from movie film.) 1963] Snow: Display of Blue-backed Manakin 173 The female, for her part, crouched with her plumage sleeked and continually turned to face the male. Sometimes she sidled quickly along the perch, sometimes she seemed to retreat a little, but for almost the whole time she remained on the main display perch, intently watching the displaying male. Copulation followed a set pattern. The male flew in from one side and landed for a moment on a perch near the female, who was facing him on the main display perch. He then jumped onto the display perch, landing beside the female after turning in the air so that he faced the same way as she, and mounted. Apart from the differences in movements and postures, there were two important general dif- ferences between this display and the jumping display. First, only one male took part and no others were seen or even heard near by, though at least one other adult male and two immature males had been displaying on this perch a few minutes before and displayed at it shortly after- wards. Secondly, it was silent, except for the oc- casional low “quaaaa” and the soft click made when the male flew in from the special perch 20 feet from the main perch. A few days later, an adult male, probably the same one, performed substantially the same display to an immature male (recognizable by his red cap) , but the display was more confused, as the immature male behaved like a female for some of the time, crouching on the display perch and continually turning and watching the male, and sometimes itself performed the bouncing flight to and fro across the display perch at the same time as the adult male. Both birds also occasionally made quick side-to-side slides on the display perch. In July, 1961, similar display was again seen between an adult male and an immature male, whose red head-feathers were hardly showing through the green. On several other occasions pairs of males were seen, at this and other display perches, both performing the floating flight and criss-crossing the display perch with buoyant leaps. On these occasions no females or immature males were seen near by. Thus the strong tendency of the males to display jointly extends even to the pre- copulatory display. The side-to-side “slides” on the display perch, mentioned above, were seen on a few other oc- casions. If they were associated with any other display it was with the floating flight rather than the jumping display. The slide is actually a rapid side-stepping with very short steps; it resembles the side-to-side sliding of Pipra species (Skutch, 1949; Snow, 1962 b) and may be a homologous display, but in Chiroxiphia it is comparatively infrequent and little ritualized. Social Organization In my earlier account, I reported that the males were found to be in pairs in the forest, and that these pairs called synchronously from perches 30 or 40 feet up in the trees and came down to perform synchronized dances on the display perches. My limited observations suggested that the members of the pairs kept together for much of the time and that each pair had its own dis- play perch, or perhaps more than one perch. Display perches of the presumed “pairs” were scattered through the forest at intervals of about 100 yards. These observations were made in un- disturbed rain forest near the top of Pigeon Peak, the highest point of Tobago. Gilliard’s ob- servations, made in much drier secondary forest nearer the coast, showed a rather different pic- ture. He found four display perches in use about 15-20 yards apart, and his observations sug- gested that the pairs of males that performed at them were drawn from a group of several males which jointly owned the four display perches, though there was some evidence of a social hier- archy within the group. Gilliard’s group con- sisted of both adult males and immatures with varying amounts of red on the crown. In July, 1958, I returned to Tobago and watched display again on Pigeon Peak. Condi- tions for observation were very poor, as the wet season was in full swing, and in addition display was slack, since the season of moult was approaching. The males I watched were mostly sitting calling solitarily; one was occasionally joined by another for a spell of synchronized calling and then jumping. Later a bird in im- mature male plumage came to the same perch but only did a few jumps and was not joined by the “owning” male, who was near by. I gained the impression that some birds had already started to moult, the “pairs” had broken up, and the few remaining adult males were giving invita- tion calls near their display perches but were not highly motivated to display. In March, 1959, I returned and spent eight days in the area earlier studied by Gilliard, with a few shorter visits to the hill forest. In the for- mer area I found three display perches in use, probably the same ones as Gilliard had found (he had taken one of the four for a museum exhibit) , at which at one time or another at least eight males (four adults and four recognizably different immatures) were present. The organi- zation appeared to be as Gilliard had described it. However, after watching carefully and trying as far as possible to keep track of individual 174 Zoologica: New York Zoological Society [48: 12 birds, I very strongly had the impression that the main display perch that I watched was in fact “owned” by a single adult male. This bird, if indeed it was always the same bird, spent much time calling from a certain perch about 20 feet up and several yards away from the display perch. Here other adult males would join it, and together they would utter the synchronized calls. The presumed owner would at times fly down to the display perch by himself and call there, as if trying to attract a partner. As usual, the normal jumping display developed when he was joined by another male, and more confused dis- plays when more than one other male was pres- ent. It was at this perch that the precopulatory display described in the previous section was seen. Shortly afterwards an adult male, thought to be the one that had copulated, chased an im- mature male from the display perch, and the same was seen a day later. During this visit, I also saw four males (two adults and two im- matures) together at a display perch on Pigeon Peak, which indicated that the situation I had found there in 1956 was not so invariable as I had thought. Watching only unringed birds, I was unable to be certain of the identity of the birds coming to the display perches, except for some of the immature males which had different amounts of red on the cap and blue on the back. These im- mature birds were generally subordinate to the adults, and when they joined in jumping displays with an adult male they were occasionally sup- planted by another adult. They were never seen performing the floating flight. On my last visit, in July, 1961, I attempted to settle the question of the ownership of dis- play perches by trapping and color-ringing some of the males in a display area. Again I chose the display area studied previously by Gilliard and myself. Three adult males and two immatures were present, but unfortunately display was slack. (There is no information on the breeding season of the Blue-backed Manakin in Tobago, but the observations made in July, in 1958 and 1961, suggest that it ends earlier than that of Manacus manacus and Pipra erythrocephala in Trinidad, in both of which breeding is in full swing in July). One of the adult males spent much time calling from the same tree as was used by the presumed “owner” in 1959, but it was only occasionally joined by another bird. There were a few bouts of jumping on the dis- play perch (the same as was used in 1959), probably by these two birds. After two days’ watching I trapped and color- ringed two males near the display perch. One was an adult male in good plumage, which from later observations was almost certainly the bird that had called regularly in the tree near by and the presumed “owner” of the display perch. The other was a bird moulting from juvenile to adult male plumage. The operation failed in its main purpose, as neither of the two ringed birds was seen again in the further week at my disposal, but it yielded a little information. No male was subsequently seen calling in the tree that had been occupied by the adult male, but two adults called near by on other perches, and after four days two birds, an adult and an immature male, were seen displaying at the display perch. But display was very sporadic, and it seemed that the frightening off of the “owning” male had practically put an end to display at this perch for the season. If, as my observations suggest, there is a dominant male at each display perch, and he is joined by his neighbors for bouts of synchro- nized calling and dancing, further questions are raised regarding the visiting adult males: does each of them also own a display perch, to which it attracts its neighbors, or do they have a sub- ordinate position at the display perch of the dominant male and no perch of their own? Of these I believe that the first is the more likely. It would be paralleled by the situation found in Pipra aureola (Snow, 1963) , in which each male has a display perch but also visits his neighbor’s display perches for joint display. If one male is dominant at each display perch, some of the puzzling features of the Blue-backed Manakin’s display can at least be partially ex- plained. In the synchronized cartwheel dance by two males in front of a female, the parts played by each male are exactly equal, a situation that does not seem conducive to successful copula- tion by one bird. But the display that immedi- ately precedes copulation is in fact quite differ- ent; it is nearly silent, and only one male is pres- ent. One may conclude that the noisy cartwheel dance is a more preliminary stage of courtship, whose function is to attract females and condi- tion them to the display perch, and that when a female comes to the perch ready for copulation the visiting males are no longer tolerated, and the dominant male alone courts her and copu- lates with her. But if this is so, there still remains the prob- lem of the evolution of this kind of behavior. Males must be sexual rivals, and it is difficult to see what advantage a male can gain by helping to enhance his neighbor’s display while neglect- ing his own display perch. His neighbors may on other occasions come to his display perch, but in either case behavior is involved which seems dis- 1963] Snow: Display of Blue-backed Manakin 175 advantageous to the individual practicing it. A fuller understanding must come from the color- ringing and intensive observation of birds at several neighboring display perches. All the spe- cies of Chiroxiphia seem to be rather common in suitable habitats, and the task should not be un- duly difficult for an observer resident in an area where they occur. Summary The display of the Blue-backed Manakin, Chiroxiphia pareola, was watched and filmed in Tobago in the course of four visits in 1956, 1958, 1959 and 1961, and its calls were tape- recorded. Males display on perches a few feet above the ground in forest. The birds keep the perches clear by plucking off the surrounding leaves, and the same perches are used year after year. Three invitation calls are described, which are uttered by single males and serve to attract other males. When a calling male has attracted an- other, they perch close together and utter a series of perfectly synchronized, far-carrying calls. Pairs of males also perform a synchronized dance on the display perches, accompanied by a vibrant twanging note. When a female comes to a display perch, the pair of males may dance in front of her in the same way. But copulation is preceded by a quite different display involving only one male, who crosses and re-crosses the display perch with buoyant leaps, while the female remains on the display perch continually turning and watching him. Immature males may take the role of the female in both these displays. The social organization is not properly under- stood, but it is suggested that there is a dominant male which “owns” each display perch, and that the males which join him for the synchronized calling and dancing probably have their own display perches in the vicinity. The problem of the evolution of this kind of joint display is briefly discussed. Literature Cited Friedmann, H., & F. D. Smith 1955. A further contribution to the ornithology of northeastern Venezuela. Proc. U. S. Nat. Mus., 104: 463-524. Goxiard, E. T. 1959. Notes on the courtship behavior of the Blue-backed Manakin ( Chiroxiphia pare- ola). Amer. Mus. Novit., No. 1942. Junge, G. C. A., & G. F. Mees 1958. The avifauna of Trinidad and Tobago. Zool. Verhand. (Leiden), No. 37. Lamm, D. W. 1948. Notes on the birds of the States of Per- nambuco and Paraiba, Brazil. Auk, 65: 261-283. Sick, H. 1942. Die Balz von Chiroxiphia caudata. Orn. Monatsber., 50: 18. 1959. Die Balz der Schmuckvogel (Pipridae). J. Orn., 100: 269-302. Skutch, A. F. 1949. Life history of the Yellow-thighed Mana- kin. Auk, 66: 1-24. Slud, P. 1957. The song and dance of the Long-tailed Manakin, Chiroxiphia linearis. Auk, 74: 333-339. Snow, B. K. 1961. Notes on the behavior of three Cotingidae. Auk, 78: 150-161. Snow, D. W. 1956. The dance of the manakins. Animal King- dom, 59: 86-91. 1962a. A field study of the Black and White Man- akin, Manacus manacus, in Trinidad. Zo- ologica, 47: 65-104. 1962b. A field study of the Golden-headed Mana- kin, Pipra erythrocephala, in Trinidad. Zo- ologica, 47: 183-198. 1963. The display of the Orange-headed Mana- kin. Condor, 65, (1): 44-48. Wagner, H. 1945. Observaciones sobre el comportamiento de Chiroxiphia linearis durante su propa- gacion. An. Inst. Biol. (Mexico), 16: 539- 546. 176 Zoologica: New York Zoological Society [48: 12: 1963] EXPLANATION OF THE PLATES Plate 1 Fig. 1. Part of the invitation call. The last five notes of the rolling churr, followed by a “chup.” Fig. 2. A synchronized “chup-chup-chup,” uttered by a pair of males sitting side by side. (The drawn-out note at approximately 6 kc. is extraneous). Fig. 3. The double “whee, whew.” Plate II Fig. 4. The vibrant buzzing call; a short, smooth buzz uttered near the beginning of a bout of jumping. Fig. 5. Two vibrant buzzing calls, made by two males jumping alternately; more drawn- out than Fig. 4. Fig. 6. Irregular buzzing calls, made by two males near the end of a bout of alternate jumping. Plate III Fig. 7. The mechanical click, made by a display- ing bird at the moment of taking off for a flight. For further explanation see the text. SNOW PLATE I I? -j kc-. FIG. 1 15 - kc. 12 - 9 - t** * i : Jill ' ' ' . t 0-25 JjiL* ttikM FIG. 3 THE DISPLAY OF THE BLUE-BACKED MANAKIN, CHIROXIPHIA PAREOLA. IN TOBAGO, W.I. SNOW PLATE II FIG. 4 If FIG. 5 FIG. 6 THE DISPLAY OF THE BLUE-BACKED MANAKIN. CHIROXIPHIA PAREOLA, IN TOBAGO, W.l. SNOW PLATE III FIG. 7 THE DISPLAY OF THE BLUE-BACKED MANAKIN. CHIROXIPHIA PAREOLA, IN TOBAGO. W.l. 1 1963] Zoologica: Index to Volume 48 111 Names in bold lace indicate new genera, species or subspecies,- num- bers in bold face indicate illustra- tions,- numbers in parentheses are the series numbers oi papers con- taining the plates listed immediately following. A Abudefduf saxatilis, 139 Acanlhurus coeruleus, 139 Aequidens curviceps, 138 portalegrensis, 138 Aetobatus narinari, 62 Agelaius icterocephalus, 10 Agkistrodon piscivorus, 140 Agraulis vanillae, 88, 97, 107, 110, 111, 113, 117, 119, 120, 122, 125, (8) PI. I vanillae forbesi, 89 galapagensis, 89 incarnata, 89 insularis, 88 lucinia, 89 maculosa, 89 nigrior, 88 vanillae, 67, 88, (7) PI. I Alulera monacanthus, 139 Amazilia chionopectus, 8 Amphiprion akallaopsis, 132, 139 laticlavius, 132, 139 percula, 132, 139 xanthurus, 132, 139 Anabas testudineus, 139, (9) PI. I Angelichihys isabelita, 139 Anguis Iragilis, 140 Anisotremus surinamensis, 138 virginicus, 138 Anthracothorax viridigula, 7 Aphyochorax rubripinnis, 136 Aphyosemion auslrale, 137 Apistogramma ramirezi, 138 Aplocheilus panchax, 137 Archosargus probalocephalus, 138 B Balistes carolinensis, 139 vetula, 139 Barbus fluviatilis, 136 Basileuterus culicivorus, 10 Belone belone, 137 Bella splendens, 139 Bifis arietans, 140 Boa constrictor, 140 Brachydanio albolinealus, 136 analipunctatus, 136 nigrofascialus, 136 rerio, 136 Bufo spinulosus, 140 C Caiman sclerops, 140 Camptosloma obsoletum, 9 Canis adustus, 40 Cantharius lineatus, 138 Carassius auraius, 136, (9) PI. VI carassius, 136 Caretta caretta, 140 Celeus elegans, 8 Centropristis furvus, 137 slriatus, 137 INDEX Ceralophrys americana, 140 Cercopithecus aethiops, 40 Certhiaxis cinnamomea, 8 Chaetura brachyura, 7 chapmani, 7 cinereivenlris, 7 spinicauda, 7 Chilomycterus schoepfi, 139 Chiroxiphia pareola atlantica, 167, 168, 170, 172, (12) pis. I-III Chlorestes notatus, 7 Chloroceryle aenia, 8 americana, 8 Chlorophanes spiza, 10 Chrysolampis mosquilus, 7 Cichlasoma biocellalum, 138 laceium, 138 iestivum, 138 meeki, 138 Clarias dumerili, 137 Coereba flaveola, 10 Colisa lalia, 139 Columbigallina minula, 7 passerina, 7 talpacoli, 7 Contopus cinereus, 9 Crocidura hirta hirta, 39 silacea, 39 Crotalus ruber, 140 Crolophaga ani, 7 Cryptomys hotlentotus, 42 Ctenosaura acanthura, 140 Cyanerpes caeruleus, 10 cyaneus, 10 Cyclarhis gujanensis, 10 Cynolebias adeotfi, 137 elongatus, 137 wolierstorffi, 137 sp., (9) PI. IV Cynoscion regalis, 138 Cyprinus carpio, 136 Cypseloides rutilus, 7 zonaris, 7 D Dacnis cayana, 10 Danio malabaricus, 136 Dascyllus auranus, 139 Dasymys incomtus incomtus, 45 Dendrocincla fuliginosa, 8 Dendroica petechia, 10 striata, 10 Dendromus mesomelas, 45 Diodon hystrix, 139 Dione glycera, 91, 97, 107, 110-112, 117, 120, 123, 125 juno, 89, 97, 107, 110-112, 117, 119, 120, 123, 125, (8) PI. I andicola, 90 huascama, 90 juno, 90 moneta, 90, 98, 107, 110-112, 117, 120, 123, 125 butleri, 90 moneta, 90 poeyii, 90 Dryadula phaelusa, 87, 96, 107, 109, 111, 113, 117-120, 122, 125, (8) PI. I Dryas iulia, 92, 99, 106-109, 111, 113, 116-120, 122, 125, (8) PI. I iulia carleri, 93 cillene, 93 delila, 93 dominicana, 94 framptoni, 94 hispaniola, 93 iulia, 67, 92, (7) PI. I juncta, 94 lucia, 94 moderata, 92 nudeola, 93 warneri, 94 Dysithamnus mentalis, 8 E Elaenia flavogaster, 9 Elaphe longissimus, 140 Elephantulus brachyrhynchus, 39 Empidonax euleri, 9 Epinephelus adscenionis, 137 guttalus, 137 morio, 137 strialus, 137 Epomophorus, 39 Eucalia inconstans, 13 Euptychia sp., 68, (7) PL I F Florisuga mellivora, 7 Fluvicola pica, 9 Formicarius analis, 8 Formicivora grisea, 8 G Gadus collarias, 137 Galbula rulicauda, 8 Genetta rubiginosa, 40 Geothlypis aequinoctialis, 10 Glaucidium brasilianum, 7 Glaucis hircuta, 7 Graphiurus murinus kelleni, 42 Gymnocorymbus ternetzi, 136 H Habia rubica, 11 Flalichoeres spp., 56 Haplochromis multicolor, 138 Heliconius aliphera, 94, 100, 107, 110, 111, 114, 121, 123, 125, (8) PL I doris, 95, 101, 107, 109, 111, 114, 121, 122, (8) PL I, 145, (10) PI. I doris, 67, (7) PL I erato, 95, 102, 107-109, 111, 114, 116, 119, 121, 123, 125, (8) PL I, 145, (10) Pis. I & II hydara, 67, (7) PL I, 155, 158-163, (11) Pis. I & II isabella, 94, 100, 107, 110, 111, 114, 117, 119, 121, 123, 125, (8) PL I isabella, 67, (7) PI. 1 melpomene, 95, 102, 107, 109, 111, 114, 119, 121, 122, (8) PL I, 145, (10) Pis. I & II euryades, 67, (7) PL I numata, 95, 101, 107, 109, 111, 114, 117, 121, 123, (8) PL I, 145 ethilla, 67, (7) PL I ricini, 95, 103, 107, 109, 111, 114, 121, 123, (8) PI. I sara, 95, 103, 107, 109, 111, 114, 119, 121, 123, (8) PL I 178 Zoologica: Index to Volume 48 [1963] lhamar, 67, (7) PI. I ielesiphe, 99 wallacei, 95, 102, 107, 109, 111, 114, 117, 121, 122, (8) PI. I Heliomaster longirosiris, 8 Hemichromis bimaculalus, 138 Hemigrammus eryihrozona, 136 ocellifer, 136 rhodosfomus, 136 unilineatus, 136 Herpesles sanguineus, 41 Hippoglossus hippoglossus, 139 Hirundo rustious, 9 Holocentrus ascensionis, 137 Hylophilus auranliifrons, 10 Hyphessobrycon bifasciatus, 136 cardinalis, 136 flammeus, 136 innesi, 132, 136, (9) Pis. MH, VI ornatus, 136 pulcher, 136 serpae, 136 Hystrix africaeauslralis, 42 I Iclalurus melas melas, 13 Icterus nigrogularis, 10 Idus melanolus, 137 K Kyphosus secalrix, 138 L Lacerla viridis, 140 Lachnolaimus maximus, 139 Lampropeltis getulus holbrooki, 140 Lebistes reticulatus, 137 Legatus Ieucophaius, 9 Leiostomus xanthurus, 138 Leistes miliaris, 11 Lemniscomys griselda, 45 Lepomis cyanellus, 13, 15-17, 19-22 gibbosus, 138 megalotis megalotis, 14 Leptodactylus pentadactylus, 140 Leptopogon superciliaris, 9 Leptotila verreauxi, 7 Lepus capensis, 42 Lophopsetta maculata, 139 Lucioperca lucioperca, 138 Lutianus apodus, 138 griseus, 138 jocu, 138 synagris, 138 M Macropodus opercularis, 139 Manacus manacus, 8 Melanotaenis nigrans, 137 Micropogon undulatus, 138 Micropterus dolomieu, 138 Miniopterus schreibersi nalalensis, 40 Mionecles olivaceus, 9 Moenkhausia pittieri, 136 Molliensia sphenops, 137 Molothrus bonariensis, 10 Momotus momota, 8 Monodactylus argenius, 138 Morone americana, 137 labrax, 137 Mus minutoides, 44 Mycobacterium anabanti, 134, forluilum, 131, 134 friedmanni, 134 marinum, 134 piscium, 134 platypoecilus, 134 ranae, 134 salmonophilum, 134 thamnopheos, 134 Mycteroperca bonaci, 138 ialcata, 138 Myiarchus tuberculifer, 9 tyrannulus, 9 Myiodynastes maculatus, 9 Myiopagis gaimardii, 9 Myiophobus fasciatus, 9 Myrmeciza longipes, 8 Myrmotherula axillaris, 8 N Naja naja, 140 Nannacara anomala, 138 Natrix natrix, 140 piscator, 140 Nolemigonus crysoleucas, 136 Noiropis umbratilis cyanocephalus, 13 Nycteris thebaica capensis, 39 O Ocyurus chrysurus, 138 Oncorhynchus gorbuscha, 136 keta, 136 kisutch, 136 nerka, 136 tschawytscha, 136 Opsanus tau, 139 Oreotragus oreotragus, 42 Orycteropus afer, 41 Oryziae lalipes, 137 Oryzoborus angolensis, 12 Osmerus mordax, 136 Otomys irroraius mashona, 46 Oius choliba, 7 P Pachyrhamphus polychopterus, 8 Panlhera pardus, 41 Panyptila cayennensis, 7 Papio ursinus, 40 Paralichthys dentatus, 139 Parula pitiayumi, 10 Perea flavescens, 138 Phaeomyias murina, 9 Phaeihornis guy, 7 longuemareus, 7 Philaelhria dido, 87, 96, 107, 109, 111, 112, 117, 119, 120, 122, 125, (8) PI. I dido dido, 87 Piaya minuta, 7 Piculus rubiginosus, 8 Pipistrellus kiihli, 40 rueppelli, 40 Pipra erythrocephalus, 8 Pipromorpha oleaginae, 9 Pitangus sulphuratus, 9 Pifuophis calender, 140 Platycichla flavipes, 10 Platypoecilus maculatus, 137 Plalyrinchus mystaceus, 9 Plecoglossus allivelis, 25, 27, (3) Pis. I-IH Plectorhynchus sp., 132 Plectostomus punctatus, 137 Pleurodema cinere, 140 marmoralus, 140 Podotricha euchroia, 91, 98, 107, 111, 112, 117, 120, 122, 123, 125 euchroia euchroia, 91 mellosa, 91 Ielesiphe, 91, 99, 107, 109, 111, 113, 120, 122 telesiphe, 92 iithrausles, 92 Pogonias cromis, 138 Polytmus guainumbi, 7 Potamochoerus porcus, 41 Pomacanthus arcuatus, 139 Pomacentrus leucostictus, 139 Premnas aculeatus, 132 biaculeatus, 139 Prionotus carolinus, 139 Pristella riddlei, 136 Procavia capensis, 41 Proteles cristafus, 41 Pseudis paradoxa, 140 Pterophyllum eimekei, 139 scalare, 139 Puntius conchonius, 136 lineatus, 136 nigrofascialus, 136 phutunio, 136 semifasciolalus, 136 tetrazona, 137 ticlo, 137 Pyrrhulina rachoviana, 136 Python molurus, 140 reticulatus, 140 sebae, 140 spiloles, 140 Q Quiscalus lugubris, 10 R Ramphocaenus melanurus, 10 Ramphocelus carbo, 11 carbo magnirostris, 68 Rana catesbeiana, 140 tigrina, 140 Raphicerus sharpei, 42 Rasbora einthoveni, 137 heteromorpha, 137 laleristriala, 137 leptosoma, 137 irilineata, 137 Ratlus (Aelhomys) chrysophilus chrysophilus, 42 (Mastomys) natalensis microdon, 43 (Praomys) namaquaensis arborarius, 44 rattus, 42 (Thallomys) damarensis damarensis, 43 Redunca arundinum, 42 Rhabdomys pumilio, 44 Rhamdia sapo, 137 Rhinolophus simulator, 40 Rhinoptera bonasus, 62, (6) PI. I Rivulus cylindraceus, 137 Roccus saxatilis, 138 S Saccostomus campestris, 45 Sakesphorus canadensis, 8 Salmo gairdneri, 136 [1963] Zoologica: Index to Volume 48 179 Sallafor albicollis, 11 caerulescens, 12 Sargus sargus, 138 Saucerollia lobaci, 8 Scarus croicensis, 53 Scalophagus argus, 138 Scelurus albigularis, 8 Scalleria naevia, 8 Soolophilus nigrita, 40 Sciurus noveboracensis, 10 Setophaga ruticilla, 10 Silurus glanis, 137 Siredon mexicanus, 139 Sparisoma aurofrenatum, 54 rubripinne, 49, 57, (5) Pis. I & II Sphaeroides maculalus, 139 Sphyrna liburo, 63 Spicara argus, 138 Sporophila inlermedia, 12 lineola, 12 minula, 12 nigricollis, 12 Slealornis caripensis, 7 Stelgidoieryx rulicollis, 9 Sublegalus arenarum, 9 Sylvioapra grimmia, 41 Symphysodon discus, 139 Synallaxis cinnamomea, 8 T Tachyphonus lucluosus, 11 rulus, 1 1 Tanagra violacea, 11 Tangara chrysophrys, 11 gyrola, 11 mexicana, 11 Tanichihys albonubes, 137 Tarbophis fallax, 140 Tafera afra, 46 Tautog onilis, 139 Thalassoma bifascialum, 54 Thamnophilus dolialus, 8 Thamnophis sirlalis, 140 Thraupis palmarum, 11 virens, 1 1 Thryothorus rulilus, 9 Tiaris bicolor, 12 fuliginosa, 12 Tinea tinea, 137 Tolmomyias flavivenfris, 9 sulphurescens, 9 Touit balavica, 7 Toxotes jaculator, 132, 138 Trachinolus carolinus, 138 Tragelaphus strepsiceros, 42 Trichogaster leeri, 139 trichopterus, 132, 139, (9) PI. V Trichopsis vittatus, 139 Trionyx gangelicus, 140 triungis, 140 Troglodytes musculus, 9 Trogon collaris, 8 strigilafus, 8 violaceus, 8 Turdus albicollis, 9 fumigatus, 10 nudigenis, 10 Tyrannus melancholicus, 9 U Umbra pygmaea, 136 V Veliliornis kirkii, 8 Vireo olivaceus, 10 Viverra civetta, 40 Volalinia jacarina, 12 Vomer setapinnis, 138 X Xenopus Iaevis, 140 Xiphophorus helleri, 137 Xiphorhynchus guttatus, 8 NEW YORK ZOOLOGICAL SOCIETY GENERAL OFFICE 630 Fifth Avenue, New York, N. Y. 10020 PUBLICATION OFFICE The Zoological Park, Bronx, N. Y, 10460 OFFICERS PRESIDENT VICE-PRESIDENT SECRETARY TREASURER Fairfield Osborn Laurance S, Rockefeller George W. Merck David H. McAlpin SCIENTIFIC STAFF: William G. Conway . . Director, Zoological Park Christopher W. Coates . . Director, Aquarium John Tee-Van General Director Emeritus ZOOLOGICAL PARK Joseph A. Davis, Jr. . . Curator, Mammals Grace Davall Assistant Curator, Mammals and Birds William G. Conway . . Curator , Birds Joseph Bell Assistant Curator, Birds Herndon G. Dowling . Curator, Reptiles Charles P. Gandal. . . Veterinarian Lee S. Crandall General Curator Emeritus Roland Lindemann .... Consultant in Mam- mal Management AQUARIUM Paul Montreuil Curator Carleton Ray Associate Curator Ross F. Nigrelli Pathologist & Chair- man of Department of Marine Biochem- istry & Ecology Klaus D. Kallman. . . .Geneticist C. M. Breder, Jr Research Associate in Ichthyology Harry A. Charipper. . . Research Associate in Histology Sophie Jakowska ..... Research Associate in Experimental Biology Louis Mowbray Research Associate in Field Biology GENERAL William Bridges . . Editor & Curator, Publications Dorothy Reville . . Editorial Assistant Sam Dunton Photographer Henry M. Lester. . Photographic Consultant DEPARTMENT OF TROPICAL RESEARCH Jocelyn Crane .Director Associates: Jane van Z. Brower William K. Gregory Lincoln P. Brower Donald R. Griffin William G. Conway David W. Snow Julie C, Emsley John Tee-Van Michael G. Emsley AFFILIATE L. Floyd Clarke Director, Jackson Hole Biological Research Station EDITORIAL COMMITTEE Fairfield Osborn, Chairman William Bridges Joseph A. Davis, Jr. Christopher W. Coates Herndon G. Dowling William G. Conway Ross F. Nigrelli Lee S. Crandall W PM Slip ^ m mEm ^ ^ a, fel# ^^I|| a j- tpi// . cf v-n <£■ jippj ifcl mW lip '%m -t tfagaJ'/' ‘ --v '‘•-*.^C4\ V 'few mm : 4&rf§£ mm sSa* <&n |r;. pKiOJjB W&y S- 4* ,ffiiO ^§§M AV h, q, 4 v //ML4 ' ffxt ■*.■■'•( .>''<& 1 Xv S^s |#8P - ?•»: / '®l* jjg|lk \I§W mm #"9*SS& rA7^;4“M i5^?SsS^ O X^g255^ <\ , p *°* ^ A 4- !&« 7 :M*J WSSsS 0fmk % j* IIka ill .. . „is. W; t> 'mfslP1 V,, 'S|$?v y 'v8-n3V£>P/£,