The Biology of Maine Species of Altica. 189 



releases the anal proleg, walks out of the old skin, and the molt 

 lis complete. This process takes about half an hour. The larva 

 begins to feed immediately. 



One can see very plainly that the invaginated portions of 

 the ectoderm molt their chitinized linings, as well as the exposed 

 parts. Under a binocular the molting of the intima of the fore 

 and hind intestines and of the tracheae shows up very clearly. 

 As is supposed to be the case with insects generally, the new 

 setae are not formed inside of the old ones (although they are 

 developed from the same trichogen cells) but lie flat on the 

 body wall, between the new and old cuticulae. They spring up 

 to the normal position as soon as they are free from the molted 

 skin. 



Coloration after the second molt. As the larva starts to 

 walk, the body is entirely bright shining orange yellow, except 

 for the brown setal punctures, the reddish brown mandibles, 

 and the translucent legs. The coloration proceeds typically 

 about as follows : 



10 min. : no change ; 20 min. : body slightly duller, but head, legs 

 and prothorax unchanged ; 30 min. : all three thoracic segments and the 

 abdomen dull, head somewhat duller, legs paler ; 40 min. : legs pale 

 gray, head still yellow, thorax and abdomen blackish; 50 min.: head and 

 prothorax duller and darker than the rest of the body, tubercles brown ; 

 60 min. : no change ; 70 min. : legs black, tubercles dark brown ; 85 min. : 

 larva darker, but no relative change ; 100 min. : head and legs deep shin- 

 ing black; prothoracic shield dark shining brown; body dark; 115 min.: 

 no change; 130 min.: prothoracic shield shining black; tubercles very 

 dark brown; 150 min.: normal coloration. 



Color description of the third instar larva, early. Head, prothoracic 

 and anal shields, and legs shining black; general body color almost 

 black (darker and duller than in early second instar), a little lighter 

 below ; dorsal and lateral tubercles dull black, ventral tubercles brown ; 

 anal proleg yellow. 



Color description of the third instar larva, late. Head, prothoracic 

 and anal shields, and legs, shining black ; body dark golden yellow 

 (darker than in late second instar), a little lighter below; dorsal and 

 lateral tubercles dull black, ventral tubercles brown ; anal proleg yellow. 

 Feeding habits. The larvae feed exclusively on the under- 

 side of the leaves, which they skeletonize in a very character- 

 istic fashion. Their work is illustrated in figure 95 of bulletin 

 195 of this Station. 



