30 Mr. J. O. Westwood's Description of a 



has treated the nomenclature of the subgenera or types of form 

 of the genus Scarabceus in the Horce Entomologicce, as thus ar- 

 ranged : — 



Genus Scarabceus. 



Sub-Genus 1. Scarab^us (Heliocantharus) Sacer. 



2. Scarab^us (Mnematium) Ritchii. 



3. Scarab^us (Pachysoma) JEscidaphis. 



4. ScARAB^us (Gymnopleurus) pUularius. 



It is not for me to decide upon the greater propriety of either 

 of these plans. If the plan of Dr. Horsfield be adopted, the sub- 

 genera o£ Macrocephalus will stand thus: — 



Genus Macrocephalus. 

 Sub-Genus 1. Macrocephalus (Stricte sic dictus) Chnicoldes. 

 2. Macrocephalus (Oxythyreus) Cylindricorms. 

 o. Macrocephalus (Ambly'thyreus) Rhomhiventris. 

 If, on the other hand, the plan of Brown and M'Leay be 

 retained, they will stand thus : — 



Genus Macrocephalus. 



Sub-Genus 1. Macrocephalus (Macrothyreus) Cimicoides. 



2. Macrocephalus (Oxythyreus) Cylindricornis. 



3. Macrocephalus (Amblythyreus) Rhombiventris. 



The name Macrothyreus being now first proposed, in allusion 

 to the large size of the scutellum in the typical species. 



Of the third of these sub-genera, I have seen but a single spe- 

 cies, of which two specimens, in a mutilated state, are preserved in 

 the collection of the Linnaean Society. 



Macrocephalus (Amblythyreus) rhombiventris. (n. s.) (PI. 2, fig. 8.) 



Laete fulvo-luteus, opacus, Isevis, capite supra postice et tho- 

 racis parte posticd nigricantibus, angulis lateralibus abdominis 

 macula fusca maculaque utrinque versus apicera, hemelytro- 

 rum membrana fuscescenti, abdomine in medio sub alas ru- 

 fescenti. Corpus totum subtus, cum pedibus, fulvo-luteum. 



Long. corp. lin. 6. 



Habitat ? 



In Mus. Soc. Linn. Lond. 



