The Biology of Maine Species of Altica. 191 



Color cycle. When the pupa is first formed, it is bright 

 yellow, except for the black caudal spines, and the brown setae 

 and spiracles. But as the pupa grows older, certain color 

 changes appear very constantly and furnish a reliable key to 

 the age of the pupa. 



On the second day after the pupal molt, the eyes become 

 light brown ; they are a medium brown by the third day, and 

 black by the fourth. By the fifth day, the mandibles are red- 

 dish brown, and at the same time, the wings become light gray. 

 They become dark gray about 24 hours later. 



The Adult. 



Emergence. The emergence of the adult is exactly like 

 the process already described for A. corni on page 169. 



Coloration. When the beetle first emerges from the pupal 

 cuticula, the prevailing body color is orange yellow. The eyes 

 are black, as are also the antennae, and the parts of the legs; 

 between the eyes the head is gray, but elsewhere it is yellowish ; 

 the labrum is yellow, the mandibles reddish brown, and the 

 maxillae and labium black. All of the coxae are black, save the 

 prothoracic, which are yellowish, as are all of the femora, 

 except distally where they are piceous ; the tibiae are black 

 proximally, and the tarsi are black dorsally. There are 2 round 

 gray spots on the pronotum. The elytra are yellow. 



In about an hour the tibiae become entirely black, and the 

 procoxae, piceous. The pronotum is gray except around the 

 edges. The wings stretch out their full length behind, fully 

 formed, and not wrinkled. After another hour, the scutellum 

 is brown, and by four hours the elytra while" still soft begin to 

 have a greenish iridescence. In 5 hours, the pronotum is 

 entirely dark, with greenish reflections. In 6 hours, the beetle 

 is almost normally colored dorsally, and the ventral surface 

 begins to show signs of coloration. The beetle is very soft when 

 it is first formed, and- it remains in the pupal cell for about 24 

 hours, or until it is fully colored and hardened. 



Feeding habits. The adults feed very freely both in the 

 spring and fall on the leaves of their food plants. They eat 

 holes through the leaf, so that their work is as characteristic as, 

 and very different from, that of the larvae. Their work on elm 



