CATERPILLARS 



THE sight of the first butterflies is always gladdening, 

 even when they are the mischievous cabbage whites 

 (Pier is). For it is an indication that summer is set- 

 ting in. Most of these early butterflies have spent the winter 

 in the pupa-state, hidden away in sheltered retreats. They 

 emerge and pair ; the females lay their eggs ; these develop 

 into the caterpillars which are often so abundant in the 

 summer months. As we have studied young creatures in 

 the sea and in the fresh waters, we may take caterpillars 

 as examples of young creatures on dry land. 



A typical caterpillar the larva of a butterfly or a moth 

 shows a hard polished head and a body of thirteen rings. 

 The head is strengthened by a median shield and two side- 

 plates bearing half a dozen simple eyes and minute three- 

 jointed feelers in marked contrast to the large com- 

 pound eyes and long feelers of the adults. In the service of 

 the mouth there are three pairs of minute appendages the 

 mandibles and two pairs of maxillae. On the second pair 

 of maxillae, fused to form the labium, there is in many cases 

 a spinneret from which a thread of silk issues. In not a few 

 caterpillars there are also mandibular glands secreting a fluid 

 which is usually defensive, occasionally digestive as well. 

 Associated with the silk-glands, the old entomologist 

 Lyonnet found accessory glands, whose secretion seems to 

 glue one thread of silk to another and perhaps helps the 

 silk to harden quickly. Each thread of silk shows a glassy 

 core of pure silk, made at the expense of the living matter 



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