204 INSECT ARTIZANS AND THEIR WORK 



of their bodies. The insects that work in this 

 material are chiefly the grubs of beetles ; but there 

 is at least one remarkable example from the moths. 

 This is a South American species, known as the 

 Hammock Moth (Perofhora sanguinolenta), from 

 the extraordinary performance of the caterpillar. 

 Several allied species make cases for themselves by 

 sewing up the edges of leaves, and carry these about 

 from place to place on their food-plants, tempor- 

 arily fixing them by silken threads, and, when they 

 have exhausted the food within reach, cutting the 

 threads and moving the case to a more leafy part. 



The caterpillar of the Hammock Moth, however, 

 utilizes its own excrement, which is of a form 

 specially suited for this use, and builds up a spindle- 

 shaped case which is enlarged as the caterpillar 

 grows. It is slung up hammock-fashion by silk 

 threads at each end ; and the caterpillar protrudes 

 sufficiently to reach neighbouring leaves, but 

 withdraws entirely when it suspects danger from 

 exposure. 



In and about pine-woods where there are the 

 huge nests of the Wood Ant (Formica rufa), we. 

 may frequently find upon the birch-trees a beetle 

 that is often mistaken for a large kind of lady- bird, 

 owing to- the fact that it has red wing-cases and 

 each of these bears two 'unequal black spots. This 

 is Clytbra quadrimaculata, the second name having 

 reference to these four black spots. It is really of 

 different shape from the Lady-birds, which are 

 rounder in outline and more convex. The reason 



