. Essays on evolution 1889-1907. Evolution. 258 THEORIES OF MIMICRY Another and equally interesting method is adopted by certain tropical American Rhynchota Homoptera belong- ing to the family Membracidae. In this remarkable group the dorsal region of the first thoracic segment (the pro- notum) is of enormous size, extending upwards and backwards so as completely to cover the insect with the exception of the head, limbs, and wings* What Natural Fig. Fig. 5. Fig 5.—A Locustid from the Sudan, Myrmecophana fallax (Brunner), seen from above and from the left side. On this insect the appearance
. Essays on evolution 1889-1907. Evolution. 258 THEORIES OF MIMICRY Another and equally interesting method is adopted by certain tropical American Rhynchota Homoptera belong- ing to the family Membracidae. In this remarkable group the dorsal region of the first thoracic segment (the pro- notum) is of enormous size, extending upwards and backwards so as completely to cover the insect with the exception of the head, limbs, and wings* What Natural Fig. Fig. 5. Fig 5.—A Locustid from the Sudan, Myrmecophana fallax (Brunner), seen from above and from the left side. On this insect the appearance of an ant is represented in black pigment, all other parts being light in colour and presumably concealed. (From Brunner von Wattenwyl, Verhandl. d. , Ges. in Wien, Bd. xxxiii, xv, figs, la & lb.) Fig. 6.—A Central American Membracid (Rhynchota Homoptera) in which the prothoracic shield resembles an ant. Thus the body of the insect which is not like an ant is concealed by an ant-like shield. The species is Heteronotus trinodosus as seen from above and the left side. The upper of the two figures seen from the side represents a female, the two other figures, males. (From W. W. Fowler, Biol. , Rynch. Homopt., vol. ii, pi. 6, figs. 16, 16 A, & 17.) Selection effects in the general body-form of other insects must here be effected, if it is to be of any value, in the shield, which is seen, and not in the body, which Is concealed. This change has been brought about, and certain species of the group have their un-ant-like bodies concealed under an ant-like shield. In other species the until so late as 1899 (David Sharp, , Insecta, vol. ii, Lond., 1899, PP- 556, 557, Fig- 269).—E. B. P., Oct. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Poulton, Edwar
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