iv AQUATIC CATERPILLARS 231 



The Duckweed, so common on stagnant water, har- 

 bours another species of aquatic caterpillar, Cataclysta 

 lemnae, which produces the Moth called the Small 

 China Marks. The larva of this species is smaller 

 than that of nympJiceata, and of variegated brown 

 colour. The top of the thorax is darker, the head 

 small and yellowish, and usually concealed in the pro- 

 thorax, which is horny and shining. The spiracles 

 are very minute. This larva makes its sheath of 

 leaves of Duckweed, attached together by silk, or of 

 the hollow stem of some aquatic plant, closing in such 

 cases one of the open ends with leaves of Duckweed 

 or bits of larger leaves. It exhibits two distinct 

 larval stages, like those of nymphceata, an earlier 

 branchial stage, which lasts till the second moult, and 

 a later tracheate stage. The life-history is completed 

 in one season, and there appear to be two generations 

 in the year. The pupa may JDC distinguished from 

 that of nymphceata by its long antennary sheaths, 

 which reach to the end of the body. The female 

 Moth runs about on the surface of the water, and lays 

 eggs, three or four together, on the under side of the 

 leaves of Duckweed. 



The species described above, though living in water 

 throughout their earlier stages, are nevertheless during 

 most of their lives air-breathers. An allied caterpil- 

 lar, Paraponyx stratiotata, possesses a more complete 

 adaptation to aquatic life, namely, branchial respira- 

 tion. Paraponyx was first described by De Geer, to 

 whom we are indebted for an excellent description. 

 The larva of this species frequents the spiny leaves 

 of Stratiotes, the Water-soldier, a plant which is a 



