94 Rev. F. W. Hope's Observations on the Genus Cassida, 



those of Asia will far outnumber those of Africa. In both of 

 the last-mentioned continents^ large tracts of diversified coun- 

 try are unexplored, and till we become better acquainted with 

 their entomology, it may seem like presumption to attempt to 

 express an opinion respecting them. At the end of this pa- 

 per will be found references to the different authors who 

 have written on the Cassidoidea of the chief divisions of 

 our globe ; I shall therefore refer the entomologist for further 

 information to the species described by them, and conclude 

 these observations with a remark on the peculiar colouring 

 matter of some of these beetles which are called tortoise or 

 shield beetles. 



Little, very little is known, respecting the substance com- 

 posing the elytra of insects, and what has been written re- 

 specting chitine or elytrine does not appear to be applicable 

 to several of the Cassidce : I allude more particularly to the 

 brilliant metallic splendour of those diaphanous species allied 

 to Cassida nobilis, Linnaeus, which are frequently ornamented 

 with greenish -gold and sulphury-silver coloured spots and 

 fasciae, the colours of which disappear when the insects are 

 dead, but may be made to reappear by immersing them in 

 hot w ater. I am inclined to think that the colouring matter, 

 alluded to in the above insects, is not to be found in the elytra, 

 but is derived from the intestines. I do not here attempt to 

 explain the cause, but merely record an impression, which 

 may be erroneous ; it is w ith a hope indeed of inducing others 

 to investigate a cause very imperfectly understood, that this 

 suggestion is now thrown out. 



CASSIDA, LiNN^us. 



Cassida, Leach, Cassidoidea, Hope, 



The first genus which I propose to separate from the mul- 

 tiplicity of forms now arranged under the term Cassida is the 



Genus Mesomphalia^, PI. IV. fig. 1. 

 Type of the genus Cassida gibbosa of Fabricius. 

 Forma fere orbicularis. 



* Mesomphalia is derived from f^iao/^(poi}^iQv, or from f4,iaos and o'^fpaAoj-, 

 the boss of a shield. 



