CHAP. V. SINGULAR AUSTRALIAN CATERPILLARS. l63 



Goodeniana K.) occasionally sleep in security, by sus- 

 pending themselves by their jaws. This unusual atti- 

 tude is,, probably, to secure themselves from particular 

 enemies. We have before mentioned the cad-worms, 

 or May-flies (Phryganea), in their caterpillar state; but 

 the economy of these insects, when about to undergo 

 a change into the chrysalis state, is still more curious. 

 This latter is a state of inactivity : it is, therefore, ne- 

 cessary that the open end of their cylindrical case should 

 be- sufficiently closed to prevent the intrusion of enemies, 

 and still admit the water necessary for their existence. 

 But these sagacious little creatures know how to do 

 this ; for they interweave a grate or portcullis at each 

 end of their fortress, which, at the same time, keeps 

 out intruders and admits the water. These grates they 

 weave with silk, spun from the anus into long threads. 

 Both Reaumer and De Geer have given us many in- 

 teresting accounts of this family ; which, by their 

 spinning, represent, in their own order, the spiders 

 among the Aptera, and the Lepidoptera among the Ptilota, 

 or winged insects. The nocturnal habits of a very 

 large proportion of the Lepidoptera, including many 

 thousand species of moths (Phalcenides Sw.), are Well 

 known ; they remain concealed during the day, and the 

 night is, to them, the season of recreation, feeding, and 

 enjoyment. Many of the larvae or caterpillars of this 

 tribe do the same ; by which means they escape de- 

 struction, not only from birds, but from many large 

 carnivorous insects. Some (like that of the Noctua 

 subterranea Fab.) never ascend the stems of plants ; but, 

 like an experienced woodman, lop down the stems at 

 their base, which, by falling, bring the foliage within 

 the reach of the caterpillar. 



(183.) But the principle of concealment is remark- 

 ably developed in a family of moths peculiar to New 

 Holland, named by Lewin, who has investigated their 

 economy, Cryptophasia. Their history may be exem- 

 plified in that of the C. irrorata Lewin (fig. 56.). The 

 egg is deposited on the bark, into which the young cater- 

 M 2 



