14 INSECT ARTIZANS AND THEIR WORK 



on the silk a fluid containing oxalate of lime, which 

 hardens and gives the chalky appearance. The 

 caterpillars of the Tussock Moth family, which 

 includes the Gold-tail, the Gipsy, and the Vapourer, 

 also mix hairs with the silk, but the cocoons are less 

 substantial than those of the Eggers ; and in the 

 Tiger Moths they are still more flimsy, the chrysalis 

 in some cases being plainly visible through them. 



The butterfly-like moth Castnia eudesmia, of 

 Chili, comes from a caterpillar that is still more 

 sparing in its use of silk. Though its cocoon is 

 five inches long, it is composed mainly of twigs, 

 leaves, and other vegetable matter merely bound 

 together with silken threads. In this respect it 

 comes close to our Goat Moth (Trypanus cornus), 

 whose huge and strong-smelling caterpillar, after 

 several years spent in the interior of trees, wanders 

 out and constructs a cocoon which is largely made 

 of rotten wood fragments held together by silk. 



The two little moths known as the Festoon 

 (Liffiacodes testudo) and the Triangle {Heterogena 

 aselld) issue from roundish cocoons attached to 

 leaves and twigs of oak, that look more like vegetable 

 galls than silken structures. The cocoon is fur- 

 nished with a distinct hinged lid which opens on 

 the pressure of the emerging moth. The related 

 American species, Lagoa opercularis, constructs a 

 similar cocoon. 



In the familiar Burnet Moths (Zygcena) the silk 

 is so closely woven and varnished with liquid silk 

 that the long spindle-shaped cocoons are parch- 



