The B ology of Maine Species of Altica. 179 



black ; body very dark olive brown above, lighter below ; general aspect 

 almost bla^k; anal proleg honey yellow. 



Color description of the second instar larva, late. Head and legs 

 shining black, prothoracic and anal shields brown ; body light greenish 

 yellow above and below, tubercles brown ; anal proleg honey yellow. 



The molt to the third instar (second molt). The process of 

 molting is the same in all of the flea-beetles studied, and is 

 described in detail under the second molt of the elm flea-beetle 

 (page i 88). 



Coloration after the second molt. After each molt the 

 larva is entirely pale honey yellow, including the head, legs, 

 shields, and tubercles, except that the spiracles are black, the 

 setal punctures brown, and the mandibles reddish brown. It 

 requires about 2 hours after the legs have been withdrawn from 

 the old cuticula to reach the normal coloration. The process is 

 typically approximately as outlined below : 



30 min. : dorsal tubercles slightly dull ; 45 min. : head, legs, shields, 

 and tubercles blackish ; 60 min. : head brown, shields, tubercles, and legs 

 gray brown, body dull yellow brown ; the apodemes of the head show 

 black, and the antennae are fully colored ; 75 min. : shields, tubercles, 

 and legs, as well as head, brown ; 90 min. : head, shields, legs, and tuber- 

 cles, dark brown, body dark ; 105 min. : head and legs brownish black ; 

 120 min.: head and legs black; 135 min.: normal coloration. 



Color description of the third instar larva, early. Head and legs 

 shining black; prothoracic and anal shields incompletely black; tuber- 

 cles dark brown, body dark olive yellow, whole aspect almost black; 

 anal proleg honey yellow. 



Color description of the third instar larva, late. Head and legs 

 shining black, prothoracic and anal shields incompletely brown; body 

 light greenish yellow above and below, tubercles brown ; anal proleg 

 honey yellow. 



Variation. There is very great variation in the color of 

 the prothoracic and anal shields in all of the instars, especially 

 the last. They may be either black or brown, and completely 

 or incompletely colored. They are more frequently brown than 

 black, especially in the older larvae, and more frequently 

 splotched than uniformly colored. 



■Feeding habits. The larvae feed exclusively on the under- 

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

 istic fashion, leaving only a network of the veins and the upper 

 epidermis. 



