526 journal of economic entomology [vol. 9 



Host Plants 



The writer has found the caterpillars feeding upon \mt three plants. 

 Named in the order of preference they are: velvet-beans (Stizolobiu7n 

 sp.), kudzu vine (Pueraria thunbergiana) , and the "horse bean" 

 {Cannavalia sp.). Some varieties and species of velvet-beans are 

 evidently preferred to others. The common "Florida velvet" is 

 always much more severely damaged than the "China" when the two 

 are planted side by side. As the caterpillars ordinarily do not leave 

 the plant on which they were hatched, any choice between plants must 

 be made by the female moths at the time of ovipositing. When 

 leaves of the two varieties were left over night in a cage of moths there 

 were, on the average, two eggs deposited on the "Florida velvet" to 

 one on the " China." Care must be taken that the leaves are of equal 

 age as the moths are less attracted to either very young or old leaves. 

 The early maturing varieties, such as the China, have the further ad- 

 vantage that if they are planted early they will, at least in northern 

 Florida, often mature most of their seed before the caterpillars become 

 abundant. 



The caterpillars feed both night and day, stopping only to molt. 

 Some determinations were made of the amount of food they normally 

 consume. The larvae were well fed at the beginning of the experiment 

 so that the amount they consumed should be not far from that usually 

 eaten in the field. Twenty-two caterpillars in the fourth, fifth, and 

 sixth instars weighing 4.8 grams ate 17 grams in 52 hours, an amount 

 equal to their own weight at the beginning of the experiment in less 

 than fifteen hours. Another lot of fifty-three larvie weighing 8 grams 

 ate 24.5 grams of leaves in 48 hours, the equivalent of their own weight 

 in less than sixteen hours. No cannibalistic tendencies were observed 

 even when the food was exhausted in cages in which many cater- 

 pillars of different sizes were confined. In this respect they differ 

 markedly from some other Noctuids such as Heliothis. 



Caterpillars in the first and second instars, when disturbed, lower 

 themselves on a silken thread. But after the second instar this thread 

 is usually not secreted. Instead the caterpillars (}uickly throw them- 

 selves to the ground by means of very rapid and violent contortions. 

 The noise they make in dropping from the upper to the lower leaves 

 as one walks through the field is quite characteristic and furnishes a 

 ready means of detecting their presence. 



Natural Enemies 

 The caterpillars are eagerly sought by many predaceous enemies. 

 One of the most important is the red- winged blackbird or "Ricebird" 

 (AgeUvus phfrniceus). These birds congregate in infested fields in 



