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under favorable conditions, the periods are about equal and 

 range from eight to ten or eleven days. 



After the insect has become full-grown and is provided with 

 wings it is fully equipped for the migratory life which it leads. 

 As will be seen by a reference to the portion of this chapter re- 

 lating to "migration", the locust gradually works its way during 

 the remaining summer and fall months to a favorable winter- 

 ing place. During this time a gradual change in color is pro- 

 gressing. From the predominating grayish or reddish-brown 

 and bright colours of the freshly winged individual it changes 

 to reddish with obscure mottlings and rose-colored wings 

 instead of the transparent ones possessed by it in the early part 

 of its career as a flying locust, in this chang-ed appearance it 

 spends the winter with thousands of its companions in a more 

 or less torpid condition tucked away from the cold among the 

 grasses and thorny vegetation so characteristic of the "Chaco'" 

 country. All this time our insect has apparently thought of 

 nothing but itself and of eating, for all our observations and the 

 reports of correspondents and others would indicate that it 

 does not begin to develop eggs before the following spring after 

 it has come out of winter quarters. In early spring, when the 

 nights begin to be warmer and fresh green grasses commence 

 to appear, the reddish color of the insect graduall}' gives place 

 to a yellowish olive and mating takes place for the first time ful- 

 ly seven months after it became a perfect insect and about ten 

 days to two weeks before egg-laying begins. After this, mating 

 ma}" occur at anytime up to death under favorable conditions. 

 Eggs are laid chiefly during the months of September, October 

 and November ; though a few are deposited as earl\' as August 

 and as late as December. 



The above seems to be the general rule in this insect's career 

 from year to year. Other reports, however, mention egg-laying 

 to have taken place in Mendoza, San Juan, Rioja, Catamxarca, Sal- 

 ta, Jujuy and Santiago del Estero during the months of January-, 

 February and March. It is these seemingly abnormal features 

 that make the whole matter one of doubt to the entomologist 

 and that require more study to enable us definitely to settle 

 whether the insect is not, after all, double brooded under cer- 

 tain conditions. 



Another feature in the life-history ol' Sc/i/stocerca paraiiensis, 

 that requires further study and additional data before we can 

 be quite certain concerning the entire subject, is the number 



