TETRAilEEOUS PLANT-BEETLES. 175 



Wholly black: ni<jrita, OUv., 0.16. 

 Black Viiiieil with red : 



Thorax red and elytra black: bieolnr, Oliv., 0.25: Ariadne, Newm., 18 : WaUhii. Crutch, 14 : 

 Lecontei, Baly, 0.20. 



Thorax red only at the sides, elytra black : notata, Oliv., 0.24. 



Side.s of thorax and shoulders of elytra retl : ncapulari-n, Oliv., 25: omogera, Crotch., 0.31. 

 Wholly or mostly red : 



Wholly red: rubra, Weber, 0.20. 



Red with a bliw.k suture : Ilarrixii, Crotch, 0.24. 



Ked usually with obscure brown or blackisli spots: 'piadrata. Fab.. 24 : rosea, Web., 15. 



Microrho2)ala, Chev., (meaning' a little eluh,) is distinguished by having 

 the antennaj apparently 8-Jointed,the four last joints being consolidated, 

 to which the generic name refers. The sculpture is usually eitlier irreg- 

 ular or imperfect, as expressed in the following table of spe(;ies : 



Kibs of elytra indistinct, and with fewer punctures. 



Thorax and atripo on ba.se of elytra red: rittata. Fab., and variety Ifftula, Lee, 23. 



Sides only of thorax and stripe on elytra red : xerene, Newm., 0.17. 

 Kibs more or less confounded with the few and large punctures: 



Punctures moderate and somewhat rejrular, color blue: cyanea. Say, 0.2'J. 



Punctures very large and contluont, color black : excavata, Oliv., 0.20. 



Surface rugulose in all directions ; black with front of thorax ; soutellum and base of antennas 

 orange: plicatula. Fab., 0.20. 

 Ribs and punctures regular and distinct : 



Color black: porcata, Melsh., 0.13. 



Color red with obscure spots : Melsheimeri, Crotch, 0. 13. 



]\rost of these species are widely distributed east of the j\[ississippi 

 river, but a few of them, fuigrifa, notata., and plicatula) have as yet been 

 observed only in the Southern States. 



Sub-faiuily CASSIDIDES. 



This sub-family is founded upon the genus Cassida of Linnaeus, a term 

 derived apparently from the Latin cassida — a helmet. They are easily 

 [Fig. 89.] recognized by their rounded and usually 



-#*^^^ ^^^^ ^"^i^^ more or less flattened form, the thorax and 

 . ^^^?; -r^^B^feT *?wttL elytra being dilated into a broad thin mar- 

 gin, beneath which the head and limbs are 

 retractile so as to be sometimes partially, 

 but usually wholly concealed. In this re- 

 spect some of them bear a close resemblance 



CAs.-in>A BmTTAT.\, Sav:— 2. larva ; 3, - •, ^i 



pupa: 4, beetit^after Riley. to souic of the genera of scaveugcr beetles, 



such as Peltis, Thyraalus and ^'iti<Ulla, but from these they can be read- 

 ily distinguished by their strongly dilated and deeply bilobed tarsi, and 

 their antenme not abruptly enlarged at the tip. They are of medium 

 or rather large size, and are often prettily colored. A few si)ecies are 

 extremely brilliant, resembling drops of burnished gold, but this bril- 

 liancy appears to be in some way dependent upon the vital functions, 

 as it disappears immediately after death- The larvie are oval, flattened, 

 prickly grubs, feeding upon the surface of leaves, often in company 

 with the perfect insects. Many of the foreign species feed upon thistles 



