152 INSECTS AFFECTING THE ORANGE. 



THE CORK-COLORED ORANGE TORTRICID. 



(Platynota rostrana, Walker.) 

 [Fig. 71.J 



The tubular webs of this species are very common and quite destruc- 

 tive to small seedling and nursery plants, as the worm is apt to select 

 the tender budding leaves at the top of the plant, and by killing these 

 check further growth. Both this and the other Tortricid leaf-rollers do 

 occasional damage to the fruit by puncturing the rind 

 beneath the shelter of a leaf, which they fasten with web 

 to its surface. 



The larva is translucent, dull yellowish-green above, 

 paler on the sides and beneath. The head is brown, and 

 the next joint bears a polished shield of the same color, 

 edged with white. A dark stripe extends along the back, 

 and a stripe of pale brown along each side. The body 

 of the larva is naked, except that each joint bears a few 

 long, fine hairs, each arising from a dot of glistening 

 white. These hairs are sensitive organs of touch. The 



FIG. 71. Platynota 



rostrana.- pupa length of the caterpillar is 18 ram d 2 ^ inch). 



shell protruding 



from folded leaf. The pupa is of slender form and chestnut-brown color. 

 It has six pairs of terminal hooks, with which it clings 

 to its tubular web. 



The male moths are much darker than the females, the upper wings 

 cinnamon in color, with oblique bands of umber, and their surface's 

 much roughened with elevated tufts and ridges of coarse scales. The 

 females are larger and the upper wings much lighter in color, the red 

 being mingled with silver-gray. In this sex the tufts of scales are very 

 minute, and the oblique bands are reduced to fine, elevated lines. 

 Length of the male, with wings folded, 10 mm (-fa inch); of the female, 

 12 mm (-nfo-mch). 



The eggs of each batch hatch simultaneously, the last caterpillar 

 quitting its egg shell a few minutes after the first. The young cater- 

 pillars immediately scatter over the plant, but hide in crevices at first, 

 and do not begin rolling the leaves until they are three or four days 

 old. They shed tneir skins five times during the eighteen or twenty 

 days of their existence as larvae. They remain eight or ten days in 

 pupa. Allowing eight or ten days for the laying and hatching of the 

 eggs, a period which is not certainly known, a single generation oc- 

 cupies less than six weeks. There are apparently four or five broods 

 during the eight warm months, and an additional brood in mild winters, 

 but the caterpillars may be found at all seasons of the year, and there 

 is in fact very little evidence of a separation into distinct broods. 



Hand-pickiug is the only remedy that can be relied upon, and by this 



