BY THE REV. T. BLACKBURN. 
1411 
with strong sexual characters, these are liable to vary in their 
development. I have, in the case of each species, selected a well- 
developed male for description, but I have seen males of almost 
every one in which the characters are much enfeebled, — the tuber- 
cles on the mentum, and the size of the prothoracic excavation 
being particularly liable to variation. In many specimens the 
frontal horn is longitudinally concave on its anterior face, but this 
does not appear to be specific. The sculpture of the elytra is on 
the same plan (as described in the case of D. Dejeani) in all the 
species of Dasygnathus known to me, but varies in intensity so 
much within the limits of a single species that it would be 
misleading to characterise it particularly. 
The following table will show the distinctive characters of the 
species : — 
A. Sides of the prothoracic excavation in the male devoid of 
lateral protuberances. 
B. Elytra conspicuously dilated to considerably behind the 
middle. 
C. Male with a recurved frontal horn. 
D. The prothoracic excavation more or less bitubercu- 
late behind. 
E. The prothoracic excavation rugosely and finely 
punctulate down the middle line (female with 
an anterior prothoracic impresssion) 
Australis. 
EE. The prothoracic excavation with 
the median line unmarked Dejeani. 
DD. The prothoracic excavation tritu- 
berculate behind trituberculatus. 
CC. Male devoid of a frontal horn inermis. 
BB. Elytra not dilated behind the middle... 
C. Frontal horn of male recurved major. 
CC. Frontal horn erect recticornis. 
AA. Sides of the prothoracic excavation in the 
male with lateral protuberances Mastersi. 
