154 



INFLUENCE OF TEMPERATURE ON BIOLOGICAL SYSTEMS 



ation of larvae which had been incubated at the hatching threshold tem- 

 perature of 15°C. Weight data from one lot of 580 eggs which gave the low 

 hatch of only 8% could be stated as showing that bugs which only semi- 

 hatched used up more than 1.5 X as much material as those that gave active 

 larvae (table 3). This seems unreasonable, especially since we have data 

 showing that individual egg weights vary considerably within a single lot 

 of eggs, and since larvae lose approximately the same amount of weight 



Table 2. Determined and calculated weight losses of larvae of oncopeltus 



incubated at various temperatures, compared with loss 



ratios calculated from oxygen consumption 



Data from table 1 and fig. 6; weights in average Mg/larva. Calculated values in 

 parentheses. 



* Corrected by factor of 255/273; see weights in table 1. 



t Calculated on basis of 'b' set using ratios 3.56 and 4.46. 



t Average temperatures obtained by 2 hr. at 25° -f 22 hr. at 15° daily, and 2 hr. 

 at 25° + 22 hr. at 13° daily, respectively. 



after incubation at either 17° or 25° irrespective of the original egg weight 

 (fig. 7A, D) . If we assume that all the embryos being incubated at 15° use 

 about the same amount of energy, then those that successfully hatched 

 would have average dry weights of 67.5 + 22.4 = 89.8 [xg which corre- 

 sponds to a live weight of about 280 /^g, whereas those that did not quite 

 succeed in hatching would have average dryweights of 58.0 + 22.4 = 80.4 

 /xg which corresponds to a live weight of a little less than 260 /xg. This 

 amount of variation is not excessive for individual egg weights within a 

 lot of 580 eggs. The obvious conclusion, then, is that at the threshold tem- 



