Part II On the Final Causes of Transformation
I.
THE ORIGIN OF THE MARKINGS OF CATERPILLARS.
Introduction, p. 161.
I.
Ontogeny and Morphology of Sphinx-Markings, p. 177.
The genus Chærocampa, 177; C. Elpenor, 177; C. Porcellus, 184. Results of the development of these species and comparison with other species of the genus, 188. The genus Deilephila, 199; D. Euphorbiæ, 201; D. Nicæa, 207; D. Dahlii, 208; D. Vespertilio, 209; D. Galii, 211; D. Livornica, 215; D. Zygophylli, 217; D. Hippophaës, 218. Summary of facts and conclusions from this genus, 223. The genus Smerinthus, 232; S. Tiliæ, 233; S. Populi, 236; S. Ocellatus, 240. Results of the development of these species, 242. The genus Macroglossa, 245; M. Stellatarum, 245; comparison of this with other species, 253. The genus Pterogon, 255; P. Œnotheræ, 256; comparison with other species, 256. The genus Sphinx, 259; S. Ligustri, 259; comparison with other species, 261. The genus Anceryx, 264; A. Pinastri, 265; comparison with other species, 268.
II.
Conclusions from Phylogeny, p. 270.
The Ontogeny of Caterpillars is a much abbreviated but slightly falsified repetition of the Phylogeny, 270. Three laws of development, 274. The backward transference of new characters to younger stages is the result of an innate law of growth, 278. Proof that new characters always originate at the end of the development; the red spots of S. Tiliæ, 282.
III.
Biological Value of Marking in general, p. 285.
Markings of Caterpillars most favourable to inquiry, 285. Are the Sphinx-markings purely morphological, or have they a biological value? 287.
IV.
Biological Value of Colour, p. 289.
General prevalence of protective colouring among caterpillars, 289. Polymorphic adaptive colouring in C. Elpenor, C. Porcellus, P. Œnotheræ, D. Vespertilio, D. Galii, D. Livornica, D. Hippophaës, 295. Habit of concealment primary; its causes, 298. Polymorphism does not here depend upon contemporaneous but upon successive double adaptation; displacement of the old by a new adaptation; proof in the cases of D. Hippophaës, D. Galii, D. Vespertilio, M. Stellatarum, C. Elpenor, and S. Convolvuli, 300.
V.
Biological Value of special Markings, p. 308.
Four chief forms of marking among Sphingidæ, 309. Complete absence of marking among small caterpillars and among those living in obscurity, 310. Longitudinal stripes among grass caterpillars, 312. Oblique striping. Coloured edges are the shadows of leaf ribs, 317. Eye-spots and ring-spots. Definition, 326: Eye-spots not originally signs of distastefulness, 328; they are means of alarm, 329; experiments with birds, 330; possibility of a later change of function in eye-spots, 334. Ring-spots. Are they signs of distastefulness? Are there caterpillars which are edible and which possess bright colours? 335; experiments with lizards, 336. In D. Galii, D. Euphorbiæ, D. Dahlii and D. Mauritanica the ring-spots are probably signs of distastefulness, 341. In D. Nicæa they are perhaps also means of exciting terror, 342. The primary ring-spot in D. Hippophaës is a means of protection, 344. Subordinate markings. Reticulation, 347. The dorsal spots of C. Elpenor and C. Porcellus, 348. The lateral dots of S. Convolvuli, 348. Origination of subordinate markings by the blending of inherited but useless markings with new ones, 349.
VI.
Objections to a Phyletic Vital Force, p. 352.
Independent origination of ring-spots in species of the genus Deilephila, 352. Possible genealogy of this genus, 358. Independent origination of red spots in several species of Smerinthus, 360. Functional change in the elements of marking, 365. Colour change in the course of the ontogeny, 367.
VII.
Phyletic Development of the Markings of the Sphingidæ. Summary and Conclusion, p. 370.
The oldest Sphingidæ were devoid of marking, 370. Longitudinal stripes the oldest form of marking, 371. Oblique striping, 373. Spot markings, 375. The first and second elements of marking are mutually exclusive, but not the first and third, or the second and third, 377. Results with reference to the origin of markings; picture of their origin and gradual complication, 380. General results; rejection of a phyletic vital force, 389.
II.
ON PHYLETIC PARALLELISM IN METAMORPHIC SPECIES.
Introduction, p. 390.
I.
Larva and Imago vary in Structure independently of each other, p. 401.
Dimorphism of one stage only, 402. Independent variability of the stages (heterochronic variability), 403. Constancy and variability are not inherent properties of certain forms of marking, 407. Heterochronic variability is not explained by assuming a phyletic vital force, 410. Rarity of greater variability in pupæ. Greater variability more common among caterpillars than among the imagines. Causes of this phenomenon, 412. Apparent independent variability of the single larval stages. Waves of variability, 416. Saturnia Carpini an instance of secondary variability, 419. Causes of the exact correlation between the larval stages and its absence between the larva and imago, 429.
II.
Does the Form-relationship of the Larva coincide with that of the Imago? p. 432.
Family groups, 432. Families frequently completely congruent, 435. Exception offered by the Nymphalidæ, 435. In transitional families the larvæ also show intermediate forms, 441. Genera; almost completely congruent; the Nymphalideous genera can be based on the structure of the larvæ, 444. So also can certain sub-genera, as Vanessa, 445. Incongruence in Pterogon, 450. Species; incongruence very common; S. Ocellatus and Populi, 451. Species of Deilephila show a nearer form-relationship as imagines than as larvæ, 454. Systemy not only the expression of morphological relationship, 455. Varieties; incongruence the rule; seasonal dimorphism; climatic varieties; dimorphism of caterpillars; local varieties of caterpillars, 456. Result of the investigation, 458. Causes of incongruence, 460. A phyletic vital force does not explain the phenomena, 461. This force is superfluous, 464.
III.
Incongruences in other Orders of Insects, p. 481.
Hymenoptera. The imagines only possess ordinal characters, 481. Double incongruence: different distance and different group-formation, 483. Diptera, 488. The larvæ form two types depending on different modes of life, 489. The similarity of the grub-like larvæ of Diptera and Hymenoptera depends upon convergence, 494. These data again furnish strong arguments against a phyletic vital force, 496. The tribe Aphaniptera, 498. Results furnished by the form-relationship of Diptera and Hymenoptera, 499. Difference between typical and non-typical parts transient, 501.
IV.
Summary and Conclusion, p. 502.
First form of incongruence, 503. Second form of incongruence, 506. General conclusion as to the elimination of a phyletic vital force, 511. Parallelism with the transformation of systems of organs, 513.
Appendix I., p. 520.
Additional notes on the Ontogeny, Phylogeny, &c., of Caterpillars. Ontogeny of Noctua larvæ, 520. Additional descriptions of Sphinx-larvæ, 521. Retention of the subdorsal line by ocellated larvæ, 529. Phytophagic variability, 531. Sexual variation in larvæ, 534.
Appendix II., p. 536.
Acræa and the Maracujà butterflies as larvæ, pupæ, and imagines, 536.
Explanation of the Plates, p. 546.