Cricket. Westwood, Intro. to the Modern Classification of Insects, vol. i. p. 440.

2. Earwig. Westwood, loc. cit. vol. i. p. 399.

3. Aphis. Packard, Guide to the Study of Insects, pp. 521, 522.

4. Scolytus. Westwood, loc. cit. vol. i. p. 350.

5. Anthrax. Westwood, loc. cit. vol. ii. p. 538.

6. Balaninus.

7. Cynips. Westwood, loc. cit. vol. ii. p. 121.

8. Ant (Formica). Westwood, loc. cit. vol. ii. p. 218.

9. Wasp. Ormerod, Nat. Hist. of Wasps, pl. i. fig. 1.

PLATE II. p. 8.

FIG.

1. Larva of Cricket. Westwood, loc. cit. vol. i. p. 440.

2. Larva of Aphis. Packard, loc. cit. pp. 521, 522.

3. Larva of Earwig. Westwood, loc. cit. vol. i. p. 399.

4. Larva of Scolytus. Westwood, loc. cit. vol. i. p. 350.

5. Larva of Anthrax. Westwood, loc. cit. vol. ii. p. 546.

6. Larva of Balaninus.

7. Larva of Cynips. Westwood, loc. cit. vol. ii. p. 121.

8. Larva of Ant (Formica). Westwood, loc. cit. vol. ii. p. 226.

9. Larva of Wasp. Newport, Art. Insecta, Todd’s Cycl. Anat. and Phys., p. 871.

PLATE III. p. 14.

FIG.

1. Chloëon. Linn. Trans. 1866.

2. Meloë. Spry and Shuckard, Coleoptera Delineated, pl. 56.

3. Calepteryx.

4. Sitaris. Spry and Shuckard, loc. cit. pl. 56.

5. Campodea. Suites à Buffon. Aptéres.

6. Acilius. Westwood, loc. cit. vol. i. p. 100.

7. Termes. Westwood, loc. cit. vol. ii. p. 12.

8. Stylops. Duncan, Met. of Insects, p. 387; Packard, p. 482.

9. Thrips. Westwood, loc. cit. vol. ii. p. 1.

PLATE IV. p. 15.

FIG.

1. Larva of Chloëon. Linn. Trans. 1863.

2. Larva of Meloë. Chapuis and Candèze, Mem. Soc. Roy. Liége, 1853, pp. 1, 7.

3. Larva of Calepteryx. Dufour, Ann. Sci. Nat. 1852.

4. Larva of Sitaris. Duncan, Met. of Insects, p. 309.

5. Larva of Campodea. Gervais' Suites à Buffon. Aptéres.

6. Larva of Acilius. Westwood, loc. cit. vol. i. p. 100.

7. Larva of Termes. Duncan, loc. cit. p. 348.

8. Larva of Stylops. Westwood, Trans. Ent. Soc. 1839, vol. ii. pl. xv. fig. 13a.

9. Larva of Thrips. Westwood, loc. cit. vol. ii. p. i.

PLATE V. p. 99.

FIG.

1-5. Protamœba.

6-9. Protamyxa aurantiaca. Haeckel Beit. zur. Monog. der Moneren, pl. 1.

10-18. Magosphœra planula. Haeckel, loc. cit. pl. v.

PLATE VI. p. 105.

FIG.

1-4. Yolk-segmentation in Laomedea. After Allman. Mon. of Tubularian Hydroids. Ray Society.

5-9. Yolk-segmentation in Filaria. After Van Beneden. Mem. sur les Vers Intestinaux.

10-13. Yolk-segmentation in Echinus. After Derbes. Ann. des. Sci. Nat. 1847.

14-17. Yolk-segmentation in Lacinularia. After Huxley. J. of Mic. Sci. 1853.

18-21. Yolk-segmentation in Purpura. After Koren and Danielssen. Ann. des. Sci. Nat. 1853.

22-24. Yolk-segmentation in Amphioxus. After Haeckel. Naturliche Schöpfungsgeschichte, pl. x.

25-29. Yolk-segmentation in Vertebrate. After Allen Thompson. Art. Ovum. Cyclop. of Anatomy and Physiology.

DESCRIPTION OF THE FIGURES.

FIG.

1. Larva of the Cockchafer (Melolontha)

2. Larva of Cetonia.

3. Larva of Trox.

4. Larva of Oryctes.

5. Larva of Aphodius.

6. Larva of Lucanus.

7. Larva of Brachytarsus.

8. Larva of Crioceris.

9. Larva of Sitaris humeralis.

10. Larva of Sitaris humeralis, in the second stage.

11. Larva of Sitaris humeralis, in the third stage.

12. Larva of Sitaris humeralis, in the fourth stage.

13. Pupa of Sitaris.

14. Larva of Sirex.

15. Egg of Rhynchites, showing the parasitic larva.

16. The parasitic larva, more magnified.

17. Egg of Platygaster.

18. Egg of Platygaster, showing the central cell.

19. Egg of Platygaster, after the division of the central cell.

20. Egg of Platygaster, more advanced.

21. Egg of Platygaster, more advanced.

22. Egg of Platygaster, showing the rudiment of the embryo.

23. Larva of Platygaster.—mo, mouth; a, antenna; kf, hooked feet; r, toothed process; lfg, lateral process; f, branches of the tail.

24. Larva of another species of Platygaster. (The letters indicate the same parts as in the preceding figure.)

25. Larva of a third species of Platygaster. (The letters indicate the same parts as in the preceding figure.)

26. Larva of Platygaster in the second stage.—mo, mouth; slkf, œsophagus; gsae, supra-œsophagal ganglion; lm, muscles; bsm, nervous system; gagh, rudiments of the reproductive glands.

27. Larva of Platygaster in the third stage.—mo, mouth; ma, mandibles; gsae, supra-œsophagal ganglion; slk, œsophagus; ag, ducts of the salivary glands; bnm, ventral nervous system; sp, salivary glands; msl, stomach; im, imaginal discs; tr, tracheæ; fk, fatty tissue; ed, intestine; ga, rudiments of reproductive organs; ew, wider portion of intestine; ao, posterior opening.

28. Embryo of Polynema.

29. Larva of Polynema.—asch, rudiments of the antennæ; flsch, of the wings; bsch, of the legs; vfg, lateral projections; gsch, rudiments of the