“If it were desired to form two distinct larval groups this could not be effected on the basis of their differences in form, but could only be based on their food-plants. The larvæ of _Heliconius_, _Eueides_, _Colænis_, and _Dione_ live on species of Maracujá (Passiflora); those of _Acræa Thalia_ and _Alalia_ on Compositæ (_Mikania_ and _Veronia_). These larval groups would agree with those founded on the form-relationships of the imagines, but unlike the imaginal groups, which can be formed into families, they would scarcely possess a generic value. “If we arrange the single species of caterpillars according to their resemblances, this arrangement does not agree with that based on the resemblances of the imagines, even if we disregard the different values of the groups. The result is somewhat as follows:-- [Illustration: IMAGINES. (Nymphalideous butterflies with tufts on wing-veins.) /---------------------------------------------------\ (Families.) MARACUJÁ-GROUP. ACRÆIDÆ. /---------------------------\ | /-------------------\ /-------------------\ | (Genera.) Heliconius. Eueides. Colænis. Dione. Acræa. | /-------\ /-------\ | (Species.) Eucrate. Isabella. Dido. Julia. Vanillæ. Juno. Thalia. | | | | | | | \----------+---------/ \--------/ \------/ \--------------------------------------/ LARVÆ.” ] * * * * * [Here follow the remarks on the habits of the larvæ in connection with their colours, &c., which have already been quoted in illustration of the use of the spiny protection (note 133, p. 293). From these facts the author draws the conclusion that the form-relationships of the caterpillars depend rather upon their mode of life than upon their blood-relationships, assuming the latter to be correctly expressed by the arrangement of the imagines at present adopted.] [Illustration: Figs. 1-4. Pupæ of _Acræa Thalia_; _Heliconius Eucrate_; _Eueides Isabella_, and _Colænis Dido_; life size.] “A glance at the above figures of the pupæ of _Heliconius Eucrate_ (Fig. 2), _Eueides Isabella_ (Fig. 3), and _Colænis Dido_ (Fig. 4), will show how great are the differences between these pupæ as compared with the close form-relationship of all the Maracujá butterflies, and with the no less close resemblance of their larvæ. A family which comprised three such dissimilar pupæ would also be capable of including that of _Acræa Thalia_ (Fig. 1).