August, ’23] 
DUDLEY & SEARLES: MARKING CUCUMBER BEETLES 
365 
camel’s-hair brush. In order to make the normally very active beetles 
more easy to handle while being marked, a method of chilling by placing 
them in test tubes in ice water was employed. By this process the 
beetles were marked effectively. It was used also with complete success 
by N. F. Howard at Birmingham, Ala., in marking the Mexican bean 
beetle. This method, however, is very laborious, about 2,000 beetles per 
diem requiring two men’s work. The principal problem dttring the 
season of 1922 was, therefore, to find some equally good marking agent 
which could be applied with much greater rapidity. 
A coloring agent was finally produced by diluting shellac with alcohol, 
using alcohol-soluble aniline dyes as the coloring matter. The most 
satisfactory solution was one composed of six parts alcohol and four 
parts commercial shellac, colored with a saturated solution of the aniline 
dye in alcohol. This dried quickly, adhered well to the body of the 
beetle, retained its color indefinitely, and did not interfere in any way 
with the normal functions of the insect. An added advantage of the 
diluted shellac over former materials used was that it could be sprayed 
on the beetles with an atomizer. This material also provided a very 
effective marking agent for other insects, especially for bees. Bees 
marked with a solution of seven parts alcohol and three parts shellac 
dyed with aniline green, remained vividly colored seven days after they 
had been marked. A solution of eight parts alcohol and two parts 
shellac with aniline green as the coloring agent proved satisfactory for 
house flies and the potato aphis, the color being particularly conspicuous 
on the wings. 
Present Technique of Marking and Recovery 
The technique of marking beetles, liberating, and recovering them, 
has developed as the work progressed and no doubt will be still further 
perfected, but a most satisfactory method followed at present is here 
described: A large number of beetles, five to ten thousand or more, 
is collected from the field. The problem of collecting beetles is very 
simple after the first squash blossoms of the season appear, due to their 
decided preference for pollen. On these they congregate in large 
numbers and it is only necessary to gather the staminate blossoms to 
collect a great many beetles. The collected blossoms are placed in 
numbered ten-pound paper sacks. All the blossoms from a certain 
garden are placed in one sack and a note made as to the number of the 
sack and the name of the owner of the garden. The sacks are brought 
to the laboratory and opened, one at a time, in a field cage. 
