256 THE NATURALIST IN AUSTRALIA. 



redoubtable contingent for the exercise of this most ingeniously improvised application 

 of the healing art. 



The remaining insects proper included in the Plate now under discussion 

 belong to the order of the Lepidoptera, or Butterfly and Moth tribe, and are 

 more especially noteworthy with reference to the bizarre aspect of their larvte or 

 caterpillars. In neither case does the perfect insect present features of note. 

 Figs. 16 to 19, depicting the first of these two forms, represent the transformation 

 phases of a small moth, referable to the genus Phorodesma. The larva is of the 

 Semi-looper or Geomiter tribe, and feeds upon a green lichen abundant on the 

 Eucalyptus trunks in the neighbourhood of Brisbane. As delineated in the enlarged 

 back view, Fig. 16, it is, while quiescent, quite impossible to distinguish it from a 

 small lichen frond. 



To accomplish this disguise the caterpillar bites off small fragments of the 

 lichen on which it feeds, and, apparently with the aid of a glutinous secretion from 

 its mouth, causes them to adhere, not only to the entire body surface, but also to 

 the long bristles that are symmetrically developed on either side. It is this latter 

 circumstance more particularly which imparts to the insect such a frond-like aspect. 

 The profile view given in Fig. 17 represents a caterpillar which has somewhat 

 outgrown its coat, the head and pro-legs being distinctly visible. A somewhat 

 analogous method of disguising itself for protective purposes is resorted to by certain 

 of the Spider Crabs of the British seas, referable to the genus Stenorhynchus, 

 which are in the habit of decorating their carapaces and limbs with detached frag- 

 ments of seaweeds to such an extent that they may be readily mistaken for growing 

 plants. The pupal stage of this lichen-feeding Phorodesma is delineated in Fig. 18. 

 As will be recognised, the cocoon is mounted on a slender pedicle, and lichen 

 fragments are extensively incorporated into its substance. The perfect moth, enlarged 

 to twice its natural size, is delineated in Fig. 19. 



The remaining Lepidopterous type that invites brief notice is represented by 

 Figs. 20 and 24 of Chromo-Plate IX., and has been identified for the writer by 

 Sir George Hampson, of the British Museum Entomological Department, with Dwwna 

 porrigens. The larva in this instance feeds on various species of the Australian gum 

 trees or Eucalypti, and has been observed by the writer in both Tasmania and the 

 Botanic Gardens of Adelaide, South Australia. The notable peculiarity in this 

 instance is the circumstance that with each skin-casting, or "ecdysis," the caterpillar 

 retains the entire head-skin attached to the short hairs at the back of its new one. 



