156 
MK. J. S. BALY ON SOME GENERA 
Fig. 9. Posterior antenna of ditto. X 400. 
10. Anterior foot-jaw of ditto. X 400. 
11. Posterior foot-jaw of ditto. X 400. 
Plate XIII. 
Fig. 1. Cymbasoma rigidum, n. sp., female. X 250. 
2. Anterior antenna of ditto. X 400. 
3. First swimming-foot of ditto. X 400. 
4. Abdomen of ditto, with attached ova and caudal appendages. 
5. First pair of swimming-feet of Aeontiophorus angulalus. x 400. 
6. Fifth foot of ditto. X 400. 
Descriptions of some Genera and Species of Galerucirue. 
By Joseph S. Baly, E.L.S, 
[Read 2nd February, 1888.] 
The examination of some extensive genera of Galerucince — Haplo- 
sonyx , Cerotoma, and others — in which the anterior acetabnla 
are described as closed or entire, has convinced me that the views 
expressed by myself in the Ent. Month. Mag. vol. xxiii. p. 26S 
are correct. In any long series of individuals belonging to these 
various genera I have almost invariably found some species in 
which, whilst certain specimens have the acetabula closed, others 
have them open, in some instances these opposite states occurring 
on the different sides of the same individual. This is strikingly 
the case in Cerotoma and Monolepta . Under such circumstances 
it must, I think, be conceded that the state of the acetabula 
cannot be regarded as a primary, even if it can be retained as a 
secondary character. It becomes therefore necessary to dis- 
cover some other and more stable means by which to divide the 
Galerucince into primary sections. This, 1 venture to suggest, 
will be found in the form and structure of the hinder portion of 
the prosternum, lii a large number of genera, for instance 
Haplosonyx, CEnidea, and numerous others, the prosternum, as in 
the Chrysomelidae and the earlier groups of the Phytophaga, is 
produced just before its base into a distinct lobe or process, the 
sides of the lobe (in cases where the acetabula are closed) being 
connected with the apices of the epimera, whilst the hinder 
margin of the lobe is free, and usually applied to the anterior 
surface of the mesosternum. In a second large sectiou of the 
family, represented by Galeruca, Aulacophora, &c., this subbasal 
lobe is entirely absent, the prosternum being connected without 
