6 BULLETIN 932, U. S. DEPARTMENT OF AGRICULTURE. 



As mentioned previously and explained later, the larvae which 

 hatch from the eggs deposited by the second brood of moths do not 

 transform into pupae and moths the same season as hatched, but pass 

 the winter in the larva stage. Hence there is, in the Grand Valley 

 of Colorado, what might be called a " partial " or " incomplete " third 

 generation. However, these eggs and larvae are known as third-brood 

 eggs and larvae. 



The " life cycle " of a generation includes the time from the deposi- 

 tion of the egg to the emergence of the moth of the same generation. 



The k ' complete life cycle " extends from the time of the deposition 

 of the egg of one generation to the deposition of the egg of the next 

 generation and, strictly speaking, should include the female sex only. 



The seasonal-history studies begin with the wintering or spring- 

 brood larvae which transform to pupae of the spring brood and from 

 which issue the moths of the spring brood. 



The moths of the spring brood deposit the eggs of the first brood, 

 which, upon hatching, are known as larvae of the first brood. Some 

 of these remain in the larva stage until the following spring, while 

 the remainder transform successively into the pupae and moths of the 

 first brood. 



The moths of the first brood produce the eggs of the second brood, 

 which, after their incubation period, result in the larvae of the second 

 brood. Some of these, like some of the first-brood larvae, are 

 wintering individuals, while the others transform and become suc- 

 cessively the pupae and moths of the second brood. 



The moths of the second brood deposit the eggs of the third brood. 

 In the Grand Valley of Colorado all the larvae of this brood pass 

 the winter, comprising part of the spring brood of pupae and moths 

 the following season. 



Wintering larvce or larvce of the sirring brood (spring-brood larvce) 

 include: All of the nontransforming larvae of the first and second 

 broods and all of the larvae of the third brood. 



Pupce of the spring brood (spring brood pupce) include : All of the 

 pupae from the spring-brood larvae. 



Moths of the spring brood (spring-brood moths) include: All of 

 the moths from the pupae of the spring brood. 



The first generation includes: 



1. The eggs of the first brood. 



2. The larvae of the first brood : 



(a) Transforming first-brood larvae; 



(b) Wintering first-brood larvae. 



3. The pupae of the first brood. 



4. The moths of the first brood. 



