164 



THE ORCEE OF COLEOPTERA. 



tion of the first veutral segment, which is as long as all the others com- 

 bined. They are between a quarter and half of an inch in length, and 

 with a dark metallic lustre, of a greenish, bronze or purplish hue. The 

 under side is paler, and clothed all over with an extremely fine silken 

 prostrate pubescence, which enables them to shed the water, when the 

 aquatic plants upon which they reside happen to be submerged. The 

 species often closely resemble each other, rendering it difficult to draw 

 the line between species and varieties. The larvae inhabit the stems of 

 aquatic plants. When about to transform, they enclose themselves in 

 silken cocoons, which are sometimes attached in rows upon the outside 

 of the plants. 



Mr. Crotch enumerates twenty-five species as inhabiting the United 

 States, two of which he describes as new, and refers the reader for a 

 full description of the others to Dr. LeConte's Synopsis in the Proc. 

 Acad. Nat. Sc, of Philadelphia, for the year 1852. 



Sub-family CRIOCERIDES. 



This sub-family takes its name from the genus Crioceris, 

 of Geoflroy, a word which literally means a r«m's horn, but 

 which is not especially appropriate to these insects, unless it 

 be by way of expressing their relationship to the preceding 

 family of Cerambycidse, in which the resemblance of the an- 

 tennae to the horns of the ram and the goat is much more 

 maJTRiLiNEATA^ striking. Like them, also, some of the beetles of the present 

 sub-family have the faculty of making a squeaking noise, by 

 the friction of one part of their bodies upon another. The Criocerides 

 differ from the great majority of Chrysomelidie, in having the thorax 

 almost cylindrical and without a lateral c^ig- so.] 



margin, and more decidedly narrower 

 than the abdomen. The antennae are 

 somewhat moniliform, of the same 

 width throughout, and about half as 

 long as the body. The larvae live ex- 

 posed on the leaves upon which they ,cZ^='=w^'^-^:^^^^!^^< '^if "" T; 

 feed ; but some of them, of which the 

 common Tbree-lined potato-beetle is an 

 example, have the remarkable habit of LEMATRiuNEATA,oiiT.:-a«.iarvffi; cpupa; 

 protecting themselves by a covering of f^o^^f^^i L'Z^Jten^^^'o.Ve Zel^I^'i 

 their own excrement. To enable them "^ '^' ^'""'^ segment-after Kiiey. 

 to accomplish this purpose, the anal opening is upon the upper side of 

 the last segment, and the excrement is pushed forwards upon the back 

 by the pressure of that which is subsequently evacuated. The Crioce- 

 rides of this country are contained in two leading genera : 



