490 



70 



in a part of the long-horned beetles {Saperdw, etc.) and in some others, 

 it is considerably wider, and affords valuable characters in classification. 

 The trochanters, or little joints at the base of the thighs, are marked tk. 

 in the figure, except the large hind trochanters, where the name is 

 printed in full. Behind the metasternum, and extending outwardly 

 fiom the hind coxse is a narrow piece marked ex. p. This is the hind 

 coxal plate. This is a very narrow piece in Harpalus, but in some of the 

 serricorn beetles {Buprestidm and Elateridw), it is much wider, and fur- 

 nishes important generic characters ; and in Haliplus, a genus of water 

 beetles, it is excessively dilated. The other parts are sufficiently named 

 in the figure. 



The antennae of the Coleoptera are usually eleven jointed and of mod- 

 erate length, l)ut they are subject to much variation both in length and 

 form, as will appear in the descriptions of the different families. The 

 subjoined figures show their most common variations, and the names by 

 which they are designated. These forms have been more particularly 

 described on a former page, when treating of insects in general. 



Explanation. — 1, filiform or thread-shaped ; 2 and 3, serrate or saw toothed ; 4, pectinate or coinb- 

 toothed ; 5, capitate or knobbed ; 6, 7, 8, olavate or club-shaped ; 9 and 10, lamellat« or plated. 



The palpi, or little jointed appendages to the mouth, also sometimes 

 furnish important characters in classification. They vary chiefly in the 

 shape of the terminal joint, which is sometimes much narrower than 

 the others, when it is called acicular or needle-shaped, and sometimes 

 much widened, so as to be in the form of a triangle or of a half moon, or 

 hatchet. 



As the terms large, small, and medium-sized are often used in speaking 

 of insects, and as these words vary considerably in force, when used in 

 different relations, we give below their average meaning when applied 

 to the Coleoptera : 



An inch or more in length, .... Very large. 



Three-quarters of an inch, Large. 



Half an inch, Medium. 



Quarter of an inch, Small. 



One-eighth of an inch or less, ... - Very small. 



The intermediate sizes are expressed by such phrases as, rather large, 



rather small, or a little above, or a little heloic the medium, etc. This 



standard applies only when speaking of any one group of beetles as 



compared with the Coleoptera generally. The same expressions will 



