October, ’23] 
HAMLIN: SEASONAL ADAPTATIONS 
423 
The fourth generation of the Australian lot numbered several thou¬ 
sand, and emergence of the adults began on April 13, 1923. On May 
18, 1923 pupation of this brood was practically completed, so it may be 
judged that the maximum emergence period would be about the middle 
of May, 1923. 
The fifth generation of the Australian batch may, then, be considered 
to date from May 15, 1923. 
Thus, during the period when the species was accomplishing its swing- 
over from the seasons of the Northern Hemisphere to those of the 
Southern Hemisphere, there were produced three generations in sixteen 
months. 
The rapidity of development of the species duiing midsummer 
(January-February) in 1923 is shown by the notes on certain cages of 
the fourth generation material. These cages received freshly deposited 
eggs about the first of January, 1923 and the adults issued therefrom 
within three months. 
From the reactions to the Australian seasons so far observed it seems 
that in the ultimate adjustment to seasons, Melitara junctolineella will 
have three generations annually instead of the two which occur in 
Southwest Texas. 
The manner in which such adjustment will be worked out may be seen 
in the transition period above reviewed. Those portions of a given 
brood which appear at unfavorable intervals are eliminated, and only 
that part of the brood which happens to appear at the opportune time 
will be preserved. Such elimination and preservation should, after a 
number of generations, accomplish a thorough adjustment of the brood 
cycle to the seasonal cycle in the new environment. 
The observed rapidity of development and the long summer of 
Queensland strongly indicate that the final adaptation of this species to 
that environment will be three broods yearly. 
The over-wintering generation will probably emerge about the middle 
of October and complete its cycle in three and one-half months. About 
the end of January, then, the second brood would begin, and the adults 
of this generation emerge about the middle of May. The progeny re¬ 
sulting from the May moths would pass the winter as larvae in approxi¬ 
mately five moriths. 
A further note of interest regarding this North American plant-feeding 
insect in Australia is that the adults are noticeably larger on the latter 
continent. 
