of certain lepidopterous larvce and pupa. 57 



especially anteriorly ; and mode of suspension. The 

 divergence from the pupse of Heterocera as a ichole is 

 also accompanied by a difference in conditions ; the 

 latter being protected from light in the earth or in 

 cocoons, while the former are freely exposed to it. The 

 natural colour of the chitinous pupal covering, i. e., that 

 colour which needs the least constructive energy for its 

 formation, seems to be red-brown. This is the common 

 colour of pupse which are shut up in opaque cocoons (as 

 D. vinula, &c.), where the colour can be of no importance. 

 It is, however, a positive advantage to those species 

 which pupate in, or upon the surface of, the earth. 

 Hence this colour is almost universal among the pupse 

 of Heterocera, being of direct (protective) or indirect 

 (by saving energy) advantage to nearly all of them. 

 One group of exceptions is very significant, i. e., the 

 colours, &c., of the pupse of EphyridcB. These Heter- 

 ocera pass the pupal state under the same conditions as 

 those of Khopalocera, freely exposed to light and air, 

 suspended by a band round the body, and by a pad to 

 which the posterior spine is attached. The conditions are 

 thus the same as those of Ehopalocera. (The suspension, 

 i. e., the way in which the condition of exposure is attained, 

 is identical with that of many pupae of Ehopalocera). 

 Corresponding with these similar conditions the pupae 

 of EphyridcB possess bright colours (PL I., figs. 9 — 12), 

 and are anteriorly angular. The bright colours depend 

 upon the transparency of the chitin, which allows under- 

 lying tints to shine through. Hence in these pupae the 

 colours disappear shortly before the appearance of the 

 imago, and the markings and colours of the latter 

 gradually become completely visible. This is also true 

 of Ehopalocera as a whole. The bright colours in these 

 cases are of protective value, either by special or general 

 resemblance. The red-brown tint is not a good pro- 

 tection, except in the situations mentioned above. The 

 warning colours of distasteful pupae are verj' different to 

 the bright protective colours of the pupae referred to 

 (e. g., compare the pupa of A. grossulariata with those of 

 the Ep>hynd(E. or Ehopalocera). 



It thus appears that the pupae of Ehopalocera form a 

 chief group corresponding to the imagines, and that the 

 differences from the other chief group of Heterocera are 

 in both cases accompanied by a divergence in the 

 respective conditions. The angular outline must also 



