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laboratory cultures of Lu . diabol ica. Such mixed oviposition of fast 

 and slow-developing eggs in the same batch by a single female has been 

 reported in several insects (Walker, 1980). According to Walker 

 (1980), for many insect species living in habitats where moisture and 

 temperature are unpredictable (such as south central Texas), the 

 optimal strategy is to produce progeny with a frequency of 

 developmental programs reflecting the probability of failure and 

 success. No single program is always a winner, and the payoffs for 

 winning programs vary within a year, from year to year. Females that 

 spread their risks by laying normal-developing and quiescent eggs, 

 avoid genetic catastrophe. This seems to be the case with Lu . 

 diabol ica , whose environment is extremely unpredictable in terms of 

 precipitation and temperature. The delayed hatching (obligatory 

 diapause) of a few of the eggs in a batch "spreads the risk" and 

 insures the survival of at least some members of the species. 



Lindquist (1936) described another type of quiescence in Lu . 

 diabol ica , which has not been reported in any other sand fly species. 

 Eggs deposited by wild-caught females in the laboratory on 14 October 

 1933 and kept in an indoor room during the winter, hatched on 29 March 

 1934, 167 days after oviposition. This phenomenon, also observed in 

 the outside colony of Lu. diabol ica during this study, probably 

 represents a true winter diapause (hibernation) in the egg stage. The 

 type of egg produced (diapause or nondiapause) is dependent upon the 

 temperature and/or photoperiod experienced by the female during the 

 preoviposition period (Walker, 1980). The first appearances of 

 diapause eggs in the outside colony, 18 October and 16 October for 

 1982 and 1983, respectively, are consistent with Lindquist's 



