21 
The insect called Water-flea, of a shining black colour, whose 
swiftness and circular motion often attracts our notice in standing 
waters, is of this genus. 
GENUS VIL BYRRHUS. Tab. 6. 
Li?in. Syst. JVat. page 568. 
The antennæ are clubbed, and end in a capitulum, or oval knob, 
which is a little compressed, and of a solid substance. 
The larvae are found on plants, and in decayed animals : their 
transformations often take place in the bodies of preserved insects, 
which they sometimes destroy. 
GENUS VIII. SILPHA. Tab. 9 and 10. 
Linn. Syst. J\ r at. page 569. 
Their antennæ are small at the base, and gradually increase in 
thickness to the end. 
The head is prominent. 
The thorax is a little flattened, and margined ; as is also the 
elytra. 
These insects are found in the spring under the loose bark of 
trees : they and their larvæ live on decayed animals. 
GENUS IX. CASSIDA, or Tortoise Beetle. Tab. 11. 
Linn. Syst. JVat. page 574. 
The antennæ of this genus are nearly filiform, increasing in 
thickness towards their end. 
The elytra have a broad margin. 
