more, resulted in re-occurrence of feeding and oviposition in 10 cases. 



Uptill now, our attempts to obtain similar re-activations by injection with 

 H. cecropia extracts have failed. 



b. Effect on metabolism. 



Oxygen consumption in the operated beetles is on a still lower level than 

 in "natural" diapause (Tab. 1). 



Re-implantation of 4— 6 corpora allata restores the normal level of respir- 

 ation (de Wilde & Stegwee, 1958). 



Table 2 



Effect of corpora allata on oxygen consumption by tissue 

 homogenates of diapausing female Leptinotarsa. 



Effect of corpora alata on oxygen consximptiom by tissue homogenates of diaJDaiusing 

 female Leptinotarsa (Warburg inethod). In each experiments measiu-ements were made 

 on aliquots of 10% homogenate, which had been homogenized for an additional ^/^ mi- 

 nute in the presence or absence (controls) of added corpora allata, obtained from ovi- 

 positing females, (after de Wilde & Stegwee, 1958). 



Effect of abdominal extract of male adult H. cecropia on oxygen consumption 

 Table 3 of tissue homogenates of Leptinotarsa decemlineata adults (Warburg method). 



Effect of abdominal extract of adult male H. cecrojjia on oxygen consumption by 

 tissue homogenates of diapausing Leptinotarsa (Warburg method). After homogenization, 

 the extract was added in 10% aceton soluting to the 10% homogenate in the Warburg 

 vessels by ineans of an Agla microsyringe. 



228 



