96 SUMMER 



where the kindred groundsel feeds their caterpillars. Burnet 

 moths have much the same contrast of scarlet spots on a dark 

 green ground, shot with blue like a rook's wing; and the 

 beautiful yellow underwing flashes like a firefly about the 

 heaths in the sun. In close company with the Mi moth the 

 brown and orange burnet noctua visits the flowers in rough 

 shrubby fields ; and at the end of summer and in early 

 autumn the bright chestnut wings of the male vapourer 

 zigzag rapidly from tree to tree, and the humming-bird hawk 

 moth vibrates with intense rapidity at the flowers. Cinna- 

 bars and burnet moths are feeble and heavy fliers, but most 

 of the other day-flying moths add vivacity and vigour to any 

 summer scene in which they appear. 



Emperor moths are the best-known examples in this 

 country of a family of silkworm moths which in Asia and 

 North America run to a great size. Their broad eye-spotted 

 wings are familiar in insect-houses and private collections, 

 for they are easily reared, largely owing to their habit of 

 protecting themselves* in a cocoon during the pupa stage. 

 The cocoon of the emperor caterpillar is spun among the 

 heather stems in July and August, and consists of a pear- 

 shaped case of a tough material like oiled paper, surrounded 

 by yellowish-brown silk, which holds it in place among the 

 herbage. Inside the tough cocoon lies the pupa, with the 

 shred of caterpillar's skin which is cast off; but the method 

 devised for the emergence of the moth in the following 

 spring is different from that of the common silkworm or the 

 caterpillar of the oak eggar moth, which also spins a cocoon 

 among the heather. The cocoons of the oak eggar and silk- 

 worm are evenly oval, but the narrow end of the emperor's 

 cocoon is open externally, and is closed inside by a set of 

 bristly silken threads, converging to a point. These effec- 

 tually close the orifice against any small creature which might 



