1. Outline of a Lepidopterous insect showing the terms employed in describing the various margins and angles of the fore- and hind-wings. 2. View of the under side of the head and first segment of the larva of a Lepidopterous insect. AA, eyes; BB, antennæ; 1, labrum; 22, mandibles; 33, maxillæ; 4, labium; 5, spinneret; _a_, coxa; _b_, trochanter; _c_, femur; _d_, tibia; _e_, tarsus; _f_, claw (highly magnified). 3. Assumed type of neuration of fore-wing of a Lepidopterous insect. (After Meyrick.) 4. Ditto of hind-wing. (After Meyrick.) 5. Side view of the head of _Vanessa gonerilla_ with proboscis extended. (Imago, Plate XII., fig. 5.) 6. Ditto with proboscis coiled up. (In both these figures only the basal portions of the antennæ are shown.) 7. Neuration of fore-wing of _Anosia erippus_. (Imago, Plate XI., fig. 1.) 8. Ditto of hind-wing. 9. Digestive system of a Lepidopterous larva. A, oesophagus; D, ventriculus; F, clavate intestine; E, ilium; H, colon; K, biliary vessels; O, spinning vessels. (After Suckow.) 10. Ditto of perfect insect. N, salivary vessels; C, sucking stomach; G, cæcum. The rest as before. (After Herold.) 11. Front view of the head of _Vanessa gonerilla_ with the labial palpi removed showing the organs of the mouth. AA, eyes; BB, antennæ (basal portion); _l_, labrum; _mm_, mandibles; _pp_, maxillary palpi; C, proboscis formed of elongated maxillæ (highly magnified). 12. Neuration of fore-wing of _Sphingidæ_. (_Deilephila_; after Meyrick.) 13. Ditto hind-wing. (After Meyrick.) 14. Proleg of caterpillar highly magnified. 15. Neuration of fore-wing of _Chrysophanus salustius_. (Imago, Plate XII., figs. 18-21.) 16. Ditto of hind-wing. 17. Fasciculate-ciliated antenna of _Chloroclystis plinthina_. (Imago, Plate VI., fig. 8.) 18. Serrate antenna of _Melanchra composita_. (Imago, Plate V., fig. 8.) 19. Pubescent antenna of _Epirranthis alectoraria_. (Imago, Plate VIII., figs. 42-47.) 20. Bi-pectinated antenna of _Nyctemera annulata_. (Imago, Plate IV., figs. 1, 2.) 21. Leg of _Agrotis ypsilon_. (Imago, Plate V., figs. 35, 36.) 1, coxa; 2, trochanter; 3, femur; 4, tibia; 5, tarsus; 6, claw; SS, spurs. (All these are highly magnified.) 22. Neuration of fore-wing of _Hepialus virescens_. (Imago, Plate XIII., figs. 16, 17.) 23. Ditto of hind-wing. 24. Head of ditto. 25. Neuration of fore-wing of _Erebia pluto_. (Imago, Plate XI., figs. 8-10.) Vein 11 absent. 26. Ditto, veins 11 and 12 concurrent. 27. Ditto of hind-wing. 28. Neuration of fore-wing of _Porina signata_. (Imago, Plate XIII., fig. 15.) 29. Ditto of hind-wing. 30. Neuration of fore-wing of _Oeceticus omnivorus_. (Imago, Plate XIII., fig. 6.) 31. Ditto of hind-wing. [Illustration: Plate I.] PLATE II. ANATOMICAL.