INTRODUCTION. o 



portion is composed of 2 pieces joined together at their sides ; one 

 narrow, adjoining tlie ScufeUum, is distinguished as the Clavus ; the 

 other, broad, as the Corhm. In 2 sections {Capsina and Antliocorimi) 

 the Cormm is prolonged into a trianguhar piece (Cimeus), which is at 

 once joined to and separated from the Corhini by a flexible suture. 

 The junction of the Corium and Claims is the Claval suture, and the 

 junction of the Corkim and Membrane is the Memhrane-suture. The 

 apical portion of the elytron is the Memlrane, the inner portion of 

 which on one elytron overlaps the corresponding portion on the other 

 elytron when the insect is in repose. 



Botli Corium and Membrane are furnished with nerves.* In the 

 Corium are at least 2 principal longitudinal nerves, and sometimes 1 

 within the anterior margin separates a narrow portion, forming tlie 

 Emholium. In the Membrane the number and position of the nerves 

 vary greatly, often even in closely allied genera. 



In some cases the nerves become obsolete, sometimes the Membrane 

 is wholly or partly wanting, and, more rarely, the Clavus or Corium 

 is but partially developed. 



The Wings are of a delicate membranous structure, furnished with 

 nerves, and fold up under the Elytra when in repose. In some cases 

 the Wings are not developed. 



The Legs differ much in the several Sections, with respect to 

 length, breadth, and form ; but they are always composed of 5 parts 

 articulated together — the basal piece or Coxa, the Fulcrum, the 

 Thigh, the Tibia, and the Tarsus. The latter consists at most of 3 

 joints, the terminal one being furnished with 1 or 2 claws, between 

 which are often 2 small membranous appendages or Pulvilli. 



The Abdomen. — Flor, in hia * Rhynchoten Livlands ' has laid much 

 stress on the structure of the abdomen as affording characters for 

 classification, describing it with great detail, and we cannot do better 

 than transfer the following portion of his description to our pages. 



* Called also veins, nervures and ribs, by various authors. None of these 

 terms are correct, iu the sense iu which they are used in the anatomy of the 

 higher animals, but as Flor well observes, no one thinks in their application to 

 insects, of their primitive meaning. 



