1909] Life History of Corizns lateralis Say. 273 



A close examination of the two plants in question will, at least, 

 suggest an answer. The petioles of pennsylvanicum, where the 

 eggs are deposited, are thickly beset with glandular hairs, while 

 those of persicaria are entirely smooth. These hairs may act as 

 the immediate stimulus to oviposition and also may serve the 

 insect in a mechanical way during the act. 



Eggs were first found early in August, and at this time young 

 in all stages of development were also found so that oviposition 

 must have begun early in July, and perhaps earlier. The eggs 

 are usually deposited on the petioles in small clusters of from 

 two to twelve, a few centimeters below where the flowers begin, 

 though occasionally they can be found singly and also sometimes 

 among the blossoms themselves. They are not attached directly 

 to the plant, but by means of a fine thread from one to two mili- 

 meters long. They are at first of a light yellow waxy color. 

 This changes to a bright red as the time for hatching approaches. 

 This occurs apparently in about six days, though this could 

 not be definitely determined as no female was observed depositing 

 her eggs, and none did so in captivity. Six days was the longest 

 time any eggs delayed in hatching after being collected. 



It seems probable that more than one brood may be reared 

 during the summer. Either this is the case or the egg-laying 

 period is very much prolonged, for eggs and young were found 

 until the autumn frosts had killed the host plants. 



The young when first hatched, like each instar when first 

 moulted, is quite red in color. Upon drying and hardening the 

 head and thorax turn black and the abdomen a light green. 

 After feeding, the latter becomes a pale greenish yellow. These 

 colors are kept unchanged until the first moult though toward 

 the latter part of the first instar a faint red spot is seen just 

 above the dorsal glands, and the black of head and thorax shows 

 a reddish tinge. Before feeding, the rostrum which is carried 

 beneath the body is longer than the insect itself and can be seen 

 protruding beyond the extremity of the abdomen. 



Within two hours after hatching, the young find their way up 

 the stem to the blossoms. The petals of this plant are persistent 

 and enclose the young seed until it is ripe. 



The rostrum is inserted into these and search is apparently 

 made for the young seed, for the rostrum can be seen to be thrust 

 in at different angles without taking it out of the first incision. 

 When they have found the spot that suits them the abdomen 



