76 



ACCOUNT OF THE PHASM1DAE, WITH NOTES ON THE EGGS. 



relation with those procured by Dr Willey ; and it seems probable that a closer 

 relationship with those of the islands to the West may be established. I may also 

 remark that a great many of the Phasmidae recorded in the older works on 

 entomology are said to come from Amboyna. I think this locality should not, 

 without confirmation, be adopted as the real habitat of the species, as I doubt 

 whether we can conclude more than that the ships bringing the specimens to Europe 

 traded with that port. The uncertainty as to these old records will I fear delay any 

 satisfactory conclusion as to the distribution of Malayan Phasmidae, at least until the 

 Ceram and Amboyna fauna has been thoroughly investigated. 



The young of Eurycantha. The adults of this genus are extremely remarkable ; 

 the number of spines on the body and the enormous size and curious armature of 

 the hind legs of the male being especially conspicuous (PI. VIII, Fig. 9). Dr Willey 

 brought back a series of specimens in various pre-adult stages which I at first 

 thought must represent more than one species, but which after comparison I believe to 

 be stages in the growth, or instars 1 , of E. horrida. Although probably no quite newly- 

 hatched specimen is present, yet it is clear that most of the conspicuous characters of 

 the species are acquired during the post-embryonic growth ; almost the only resemblance 

 between the youngest specimen and the adults are that both are broader and shorter 

 than is usual in Phasmidae. The number of segments in the antennae is of great 

 importance in the classification of the family ; our series of E. horrida indicates 

 a remarkable change in this feature during life. The youngest specimen we have has 

 only nine segments on the antenna, whereas the adult has upwards of forty 2 . Never- 

 theless in the young the antennae are proportionally rather longer than in the adult, 

 so that we have present the phenomenon of a great increase in number of segments, 

 accompanied by an arrest of growth in comparison with other parts. Although our 

 series is not sufficiently good to enable me to state with certainty the manner in 

 which the change occurs, it would seem to be due to many of the segments of the 

 young antenna dividing at once into a considerable number — about six — of smaller 

 segments (PI. VIII, Fig. 8). 



The median segment of Phasmidae. It is commonly stated that the third thoracic 

 segment in Phasmidae is formed by the union of the first abdominal segment with 

 the metathorax. This view is stated by Brunner v. Wattenwyl 3 , and is adopted by 

 Heymons 4 . The adult insect so far as its structure goes does not exhibit positive 

 evidence in support of this view so far as the sternum is concerned. On looking at 

 the metasternum it is easy to imagine that one can detect in it a sufficiently 

 complex structure to justify the view above alluded to ; but on comparing it with 

 the mesosternum exactly the same parts seem to be also present there (Fig. 10). As 

 there can be no question of an abdominal sternite being added to the mesothorax, 

 the view that one is added to the metathorax should be confirmed by observation 

 of the development. 



1 For definition of this term refer to Cambridge Nat. Hist. v. p. 158. 



2 Only one antenna of the adults is intact, and this has 49 segments. 



3 Brunner v. Wattenwyl, Morph. Bed. Segm. Orthopt. Wien, 1876. 



4 Heymons, SB. Ak. Berlin, 1897, p. 367. 



