366 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
This method of collecting beetles in the field serves two purposes; 
to recover marked specimens and to obtain a supply for marking. 
As the beetles emerge from the sack, any marked ones can be easily 
distinguished and captured. When a marked beetle is found, the color 
with which is it marked determines the point at which it was released 
while the number of the sack from which it issued gives the location 
of its collection. 
The unmarked beetles collected in the large field cage are transferred 
to a small cylindrical screen cage 3 inches by 7 inches and then taken, 
as needed, to test tubes which are graduated at the points to which 100, 
200, 300, 400, and 500 beetles (by actual count) will come. In this 
manner, an accurate estimate may be made of the number of beetles to 
be marked without an actual count. A field cage is used in which to 
mark the beetles. It is fitted on each side with cloth containing head 
and arm holes and has a 20-mesh screen bottom. By employing 
this type of cage, it is possible for two operators to work at one time 
and mark more accurately and quickly. One operator shakes the 
beetles, about thirty at a time, from the test tube on the platform 
and then sweeps them from the platform to the floor of the cage after 
the other operator has sprayed them with the colored solution. The 
marking platform is a box of screen 2 inches by 4 inches by 6 inches set 
in the center of the cage. The beetles are marked on this platform and 
then swept immediately from it, in order to avoid giving them two coats 
of the spray material. If not over thirty beetles are shaken from the 
test tube to the platform at one time, it is possible for the person operat¬ 
ing the atomizer to spray all of the beetles before they can escape. All 
marking is done out of doors in order that the shellac may. dry more 
quickly and to prevent the operators from inhaling more of the spray 
than necessary. The marked beetles quickly crawl up the sides of the 
screen cage which facilitates the drying of the shellac. When all the 
beetles available at one time have been marked, they are taken in a 
cage to some predetermined spot, either in a cucurbit garden or some 
distance from one, and released. The cages are visited about 24 
hours later and all beetles, which have not flown away, are counted and 
subtracted from the number marked. Therefore, the “number re¬ 
leased” is the actual number which fly, or possibly crawl, away. 
Experiments in Flight 
During the summer of 1922, three lots of beetles, totaling 25,786 
individuals, were marked and released. The results obtained are 
given in the following table. 
