CODLIXG MOTH 1ST COLORADO. t 



The second generation includes: 



1. The eggs of the second brood. 



2. The larvae of the second brood : 



(a) Transforming second-brood larvae; 

 (5) Wintering second-brood larvae. 



3. The pupae of the second brood. 



4. The moths of the second brood. 



The third generation {not complete in the Grand Volley) includes : 



1. The eggs of the third brood. 



2. The larvae of the third brood, all of which are wintering 



individuals. 



METHODS AND REARING APPARATUS EMPLOYED IN THE LIFE- 

 HISTORY STUDIES. 



The methods used in the study of the biology of the codling moth in 

 the Grand Valley were in most respects like those employed in simi- 

 lar investigations of the bureau at other places. 



The rearing apparatus likewise conformed with that previously 

 used, with the exception of an improved cocooning rack, devised by 

 Mr. Van Leeuwen. This device was made of wooden strips 8 inches 

 long, If inches wide, J inch thick, having two rows of compartments 

 or cells, each cell of which would accommodate one codling moth 

 larva. These cells were covered with a strip of celluloid, through 

 which the transformation of the insect could be observed, and the 

 record of the observations was kept by placing a reference number 

 at the head of each cell in the space provided for that purpose. 

 After the inspection of the insects, the cells were covered by a strip 

 of wood one-eighth inch in thickness, which was held in place by 

 means of wire clamps made from paper clips. Three views of the 

 cocooning rack are shown in Plate III: a, the rack with cover re- 

 moved, showing the cells and larvae within as well as the reference 

 numbers; o. side view, showing cover held in place by wire clamps; 

 e, top view. 



The cages used in the studies usually consisted of glass battery 

 jars, 6 by 8 inches, covered with cloth tops which are held in place 

 by rubber bands. 



The oviposition cages consisted of the regular battery jars, the 

 bottoms of which were covered with a 2-inch layer of slightly moist 

 sand. A fresh twig of apple or pear foliage was placed daily in 

 each cage, as was also a small piece of sponge moistened with a solu- 

 tion of brown sugar. 



The incubation cages, in which the eggs were kept, were similar 

 to those used for oviposition purposes. The leaves, on which the 

 eggs had been deposited, were held in a flat position between two 

 pieces of wire screen for a day or more to prevent curling while they 

 dried. 



