238 CATERPILLARS AND THEIR MOTHS 



On the tenth day they molted, being clear yellow at 

 first, but becoming black and yellow as before. 



On the eighteenth day they molted again. Their 

 heads were yellow, with five black marks. Their bodies 

 were yellow, with a dorsal line of transverse black 

 dashes. The second and third segments had four 

 black tubercles and two yellow ones, one on each side 

 of the dorsal line. The others had six black tubercles, 

 except the eleventh, which had two black ones, and 

 one yellow one on the dorsal line, and the anal seg- 

 ment, which had two tubercles, connected by a black 

 crescent over each prop. 



Part of the crawlers were eating sassafras and were 

 twice as large as those on ash, so more were given 

 sassafras. 



On the twenty-seventh day the third molt came. 

 The caterpillars' heads were bright yellow, marked 

 with black. Their bodies were greenish, covered with 

 a waxy bloom which made them look almost white 

 on the back. The first segment had two black dashes, 

 the second and third, each, two orange tubercles, 

 ringed with black, on the dorsum. The eleventh seg- 

 ment had one yellow tubercle, with a black ring. All 

 the other tnbercles were much smaller than before, 

 hardly more than dots. The anal shield was deep yel- 

 low, with a black mark. The anal props were edged 

 with black. 



On the thirty-third day they molted for the fourth 

 time. The only changes were in the tubercles. The 

 orange ones on the thorax became coral-red, with black 

 rings ; that on the eleventh segment was deep yellow ; 

 the black ones were replaced by blue-black dots just 

 raised above the level of the skin. 



