no NEW ZEALAND ENTOMOLOGY. 



to its victims. The purple spots on the tibiae of this insect 

 are very noticeable, and resemble small drums in structure, 

 hence they are regarded by Mr. A. H. Swinton (" Insect 

 Variety," page 239), as the organs of hearing. These curious 

 drums may be also found in insects belonging to nearly all 

 the remaining families of the Orthoptera, but, as we find no 

 auditory organs occupying a similiar situation in any other 

 groups of insects, I think that Mr. Swinton's explanation 

 of their function must be regarded at present as a 

 somewhat doubtful one. 1 



Family 

 Acanthoderus horridus (Plate XIX.). 



The curious Stick Insects are familiar to most people 

 from their remarkable similarity to the twigs of trees. 



The present species is one of the largest, the mature insect 

 frequently attaining a length of five inches. It is best 

 taken at night, when it may be readily discovered, feeding 

 on the leaves of shrubs, and suddenly becoming perfectly 

 motionless when the lantern is turned upon it. The favour- 

 ite plant for this (and indeed most of the species) is the 

 white rata, upon which they are often seen in large numbers 

 when the entomologist is collecting Lepidoptera in autumn. 

 One of the commonest species found in this way is Bacillus 

 (hookeri?) chiefly remarkable for its great sexual disparities, 

 the male resembling a very slender stick about twenty-eight 

 lines long, while the female is nearly half as long again 

 (thirty-eight lines), and much more stoutly built. A 

 more systematic investigation of this family is needed 

 before we can pretend to correctly determine the various 

 species, as there is little doubt that in other cases the 

 sexes will be found quite as divergent. In addition to this 



1 For account of the earlier stages of this, or a closely allied insect, 

 see " Transactions of New Zealand Institute," vol. xvi. p. 114. 



