148 



A. S. SHULOV AND M. P. PENER 



XVTTT 



XK 



XE 



Fig. 2. Embryos of Locusta migrator ia migratorioides (R. and F.) (stages 

 XIV, XVIII, XIX) and of Dociostaiirus maroccanus Thnb. (stage XIV, in 

 the right corner (punctated)). {Locusta embryos according to Shulov and 

 Pener-*, Dociostaurus embryo according to Bodenheimer and Shulov^^). 

 The embryos of stages XVIII and XIX of Locusta are on the same scale, 

 but that of stage XIV is magnified to match the size of embryo oi Dociostau- 

 rus maroccanus shown. The thoracal appendages of the Dociostaurus embryo 

 show more advanced differentiation, in comparison to the Locusta embryo 



of the same stage. 



ready morphologically for katatrepsis, but not physiologically. 

 This type of interruption is known in Dociostaurus^ and in 

 diapause-bound eggs oi Locustana pardalina^. The diapause may 

 last from two to several weeks. It seems that in Dociostaurus 

 this period is not influenced by temperature or humidity, but in 

 Locustana the addition of water at this time has apparently an 

 adverse eff"ect, i.e. causes prolongation of the diapause. 



The fourth type of interruption comprises embryos at the end 

 of anatrepsis which will resume development if provided with 

 a sufficient amount of water. The interruption in such cases may 

 persist for various lengths of time, ranging from five months in 

 the eggs of Calliptamus paJaestinensis^ to more than three years 

 for the eggs of Locustana pardalina'^^ (Table II). 



The species m_entioned in Table II (part A) are typical for 

 arid climates. Their eggs are laid mostly in dry soil. Such species 



