TETRAMEROTTS PLANT-BEETLES. 
175 
Wholly black: nigrita , Oliv., 0.16. 
Black varied with red : 
Thorax red and elytra black: bicolor, Oliv., 0.25: Ariadne, Newm., 0.18 : Walshii, Crotch, 0.14 : 
Lecontei, Baly, 0.20. 
Thorax red only at the sides, elytra black : notata, Oliv., 0.24. 
Sides of thorax and shoulders of elytra red: scapularis, Oliv., 0.25: omogera, Crotch., 0.31. 
Wholly or mostly red : 
Wholly red: rubra, Weber, 0.20. 
Red with a black suture: Harriaii , Crotch, 0.24. 
Red usually with obscure brown or blackish spots: q uadrata, Fab., 0 24 : rosea, Web., 0.15. 
Microrhopala, Okev., (meaning a little club,) is distinguished by having 
the antennae apparently 8-jointed, the four last joints being consolidated, 
to which the generic name refers. The sculpture is usually either irreg- 
ular or imperfect, as expressed in the following table of species : 
Ribs of elytra indistinct, and with fewer punctures. 
Thorax and stripe on base of elytra red: vittata, Fab., and variety leetula, Lee., 0 23. 
Sides only of thorax and stripe on elytra red : xerene, Newm., 0.17. 
Ribs more or less confounded with the few and largo punctures: 
Punctures moderate and somewhat regular, color blue: cyanea, Say, 0.23. 
Punctures very large and confluent, color black: excavata, Oliv., 0.20. 
Surface rugulose in all directions ; black with front of thorax; scutelluin and base of anfcenme 
orange: plicatula, Fab., 0.20. 
Ribs and punctures regular and distinct : 
Color black: porcata, Melsh., 0.13. 
Color red with obscure spots : Melsheimeri, Crotoh, 0.13. 
Most of these species are widely distributed east of the Mississippi 
river, but a few of them, ( nigrita , notata, and plicatula J have as yet been 
observed only in the Southern States. 
[Fig. 69. 
Sab-family CASSDDIDES. 
This sub-family is founded upon the genus Gassida of Linnmus, a term 
derived apparently from the Latin cassida — a helmet. They are easily 
recognized by their rounded and usually 
more or less flattened form, the thorax and 
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 
Cassida iuvittata, Say:— 2, larva ; 3, 
pupa; 4, beetle — after RUey. to some or the genera of scavenger beetles, 
such as Peltis, Thymalus and Nitidula, but from these they can be read- 
ily distinguished by their strongly dilated and deeply bilobed tarsi, and 
their anteume not abruptly enlarged at the tip. They are of medium 
or rather large size, and are often prettily colored. A few species 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 larv® are oval, flattened, 
prickly grubs, feeding upon the surface of leaves, often in company 
with the perfect insects. Many of the foreign species feed upou thistles 
