OBSEKVATIONS ON THE SPINED SOLDIER BUG. 



157 



OBSERVATIONS ON EGG LAYING AND DURATION OF INCUBATION. 



The female became adult on July 16 and deposited her first batch 

 of eggs on the ninth day thereafter, 

 data relating to eggs laid by this insect : 



The following table gives the 



Data on egg laying and incubation. 



« The " recorded fraction " of a day is obtained as follows : For an egg batch recorded 

 as deposited in the forenoon, one-half day (noon to midnight) has been added to the inter- 

 vening days: if recorded as deposited in the afternoon, one-fourth day (6 p. m. to mid- 

 night) has been added to the intervening days; if recorded as hatching in the forenoon, 

 one-fourth day (midnight to 6 a. m.) has been added to the intervening days; if recorded 

 as hatching in the afternoon, one-half day (midnight to noon) has been added to the 

 intervening days. " Corrections " are based on one-half of the sum of the period pre 

 ceding the record of deposition and the period preceding the record of hatching during 

 which no observations were made. While in general the incubation periods without doubt 

 were made more nearly correct by the method of correction adopted, in some cases it 

 resulted in slight discrepancies in the ratio of the incubation periods to the mean tem- 

 peratures of the intervening days. 



* The temperature records are from the Bulletins of the Meteorological Observatory of 

 the Massachusetts Agricultural College. The insects under observation were kept close to 

 a north window which was open daily from 8 a. m. to 6 p. m. Under the conditions the 

 daily mean temperature was probably very close to that recorded at the observatory. 



<■ l^nhatched eggs fed upon by nymphs of batch No. 3. 



<* Fourteen infertile ; 16 fertile, but failed to hatch. 



« Nine infertile ; 5 fertile, but failed to hatch. 



