104 
SPOLIA ZEYLANICA. 
distance between the front of head and apex of the abdominal 
appendages. This is unreliable owing to shrinkage of the body. 
Taking the pronotal measurements, for example, as represented in 
the three series given in the sequence, the short-wing gracilis , the 
long-wing gracilis , and long-wing attenuatus, place modes, the 
result of geographical segregation, are detected and sufficiently 
well marked in degree of divergence and of isolation to distinguish 
the species, though strictly speaking, they are not severed entirely. 
The Origin of Denticles and Spines. 
That some of the spines and denticles on the Tettigid body 
have originated at different periods in the evolution of the species 
is indicated by the following observations :—Six nymphs of 
Griotettix tricarinatus , Bol., from seven to seven and a half 
millimeters in length, and having the pronotum extended back¬ 
wards nearly to the knees of the posterior femora, not only differ 
from, the adult in the size of the body, but especially in the 
character of the lateral lobes of the pronotum. In these nymphs 
which are presumably in the stage before the last moult, the lateral 
lobes are slightly laminate, but scarcely at all or very slightly 
acute produced outwards, and are obliquely truncate behind. 
From this it is inferred that the rather long spines arming the 
lateral lobes in the adult do not appear until after the last ecdysis, 
at which time the pronotal apex and wings, including the elytra, 
coincidently attain their full development. That these spines of 
the lateral lobes are of recent origin is shown by their variable 
form in the adult, together with their absence or vestigial character 
in the later nymph stage as before intimated. A study of the 
denticles on the lower margins of the femora in Scelimena logani, 
Hanc., on the other hand, leads me to think that these structures 
must date back to a much more remote period, for they are present 
in a well-developed condition in the nymphs of that species. 
Faunal Resemblances. 
Among other known facts accentuated by the present study 
is the close similarity existing between the faunae of Ceylon, 
Oriental India, Burma, the Philippines, and Java. It will 
suffice here to refer only to one noteworthy species, Hedotettix 
gracilis , De Hann., which ranges over the localities named. Fully 
as important is the fact that certain genera and species as discussed 
in the sequence are confined to the Island of Ceylon. Wallace 
(1895) describes the “ Oriental region” as comprising all Asia, south 
of the Palfearctic limits, and along with this the Malay Islands as 
far as the Philippines, Borneo, and Java. It was called the Indian 
region by Sclater, Before this Wallace (1876, pp. 326- 327), saw the 
