THE CASE MOTHS. 657 



a portion of the remarkable silk-spinning family of the Bomhycidce, 

 but offer many points distinct in themselves, which entitle them to 

 rank, as recent lepidopterists agree, as a separate and well-defined 

 tribe. 



Their geographical distribution is extensive, since they are found 

 in Europe, in ISTorth and South America, the West Indies and 

 Mexico, in northern India and Ceylon, in China, the South Sea 

 Isles, and Australia, being most abundant in subtropical regions. 

 Wonderfully few species are described as natives of the United 

 States, while in California, unfortunately, three have been discovered 

 solely in the larval state, the more mature conditions of the species 

 as yet eluding detection. But there, as in various other parts of the 

 globe, probably greater numbers await the industry of observers. 



Among English-speaking folk, the common appellations for the 

 moths originate in the same circumstance as the popular term in 

 Germany — house-builders, sack-bearers, basket-carriers, basket- 

 worms, case moths; by these names they pass in England, America, 

 and Australia, on account of the singular habitations or sacks 

 they weave for the well-being of the caterpillars in the early 

 stages of their growth. Through the whole of their larval life 

 they carry the protecting structure about with them; and as re- 

 gards the apterous female, she never leaves this home in which 

 she dwelt while in larva — one of the oddest incidents in this odd 

 economy — but reaching maturity, and bringing forth her young, 

 dies at last, without once quitting her self-constructed prison. 

 She deposits her ova, an immense number, within the body of the 

 case, closely enveloped in some species in a short silky down, and 

 almost as soon as hatched the larvae force their way out of the pu- 

 parium which had served for the defense of the eggs, deserting their 

 early abode, and going into the world to follow independent lives. 

 Escaping in crowds from the lower end of the tube, to some twig 

 or leaf, they immediately commence to prepare for themselves each 

 a separate case, arranged in every respect as the larger ones, even 

 before they have taken food. 



Particles of wood or bark, leaves, sticks, straws, lichens, mosses, 

 and other vegetable substances form, among the different species, 

 the outer covering or decorative fortification of the house; the in- 

 terior is lined with soft silk, and interwoven silky threads likewise 

 bind together the external fragments. In the building materials 

 chosen, and their arrangement, Metura elongata is a most inter- 

 esting architect. Strengthening the large elongate ovate bag of 

 silk, and worked into it, irregularly, numerous rows of short sticks 

 appear, rather distantly separated, and about half an inch long, gen- 

 erally speaking, but toward the lower end there are usually several 



VOL. LIII. — 45 



