December, '15] 



SELL- CUCU^IBER BEETLES 



517 



A study of the feeding habits of this insect is interesting. It \yill not 

 eat just any plant and must become adapted to a change of food. 

 Even when confronted with starvation a number of them would not 

 eat the leaves of mullein, thistle, artichoke, pond rushes, dog-fennel, 

 onion tops, red oak, chestnut, maidenhair, pine, spruce or cottonwood. 

 From a diet of beet leaves the^^ did not take readily to eating leaves of 

 maple, peach, plum, cherry, gooseberry, currant, potato or tomato, 

 but finally developed an appetite for them. 



After a pair had been fed on beet leaves for several daj^s prickly 

 lettuce was substituted. They did not eat it for two days, then, after 

 a period of six hours from the time they had eaten rather heartily, the 

 male died. In the field prickly lettuce is a perf erred host plant of 

 great numbers. 



Another pair that had been eating beet leaves were fed apricot 

 peelings. They began eating before night but died the next da}^ 



Ten beetles were fed on beet leaves for six days. After being with- 

 out food for one day they were given apricot peelings. Six of them 

 died but the other four adapted themselves to the change of diet. 

 After the university had received information of damage to potato 

 tops some experiments in adapting beetles to this food were attempted. 

 Twenty-five beetles that had been eating beet leaves were fed potato 

 tops. At first they would not eat and two of them died. In four 

 days the others had become accustomed to the change. Then they 

 were also given beet leaves but they preferred potato tops. When the 

 potato tops were removed they fasted one day and then resumed the 

 beet leaf diet. Xone of them died. 



Fifty beetles, taken in a beet patch, were fed potato tops. The 

 second day thej- began to eat and two of them died. After they had 

 been eating well for three days they were fed beet leaves which they 

 would not eat at first. In two days they had adapted themselves to 

 the change. 



Under certain conditions this species would eat some part of the 

 flower or fruit of every plant upon which it was observed during the 

 entire period of this investigation. 



Occasionally one of the beetles was found in a colony of aphids, 

 walking around among them and gathering up the honey dew but it 

 did not seem to be guided by a sense of smell since numbers of them 

 did not congregate around the bait. 



Field Habits. In order to study the range and field habits of 

 this insect large numbers of them were marked by painting with a 

 brush and ink. Several kinds of ink were tried with variable results. 

 White ink and black India ink were fairly successful but red India- 

 proved to be the most satisfactory. 



