The Mason-Wasps 



lated circles are distributed in two trans- 

 versal rows over the middle segments and 

 have a black dot in the centre, surmounted 

 by a black cilium. On the third and fourth 

 and also on the penultimate segment, each 

 circle has two black dots and two cilia. This 

 is the rule. 



The exception is supplied by two head 

 of game in the whole course of my observa- 

 tions. These two had a pale yellow body, 

 with five longitudinal brick-red stripes and 

 a few very rare cilia. Head and prothorax 

 brown and shiny; length and diameter as 

 above. 



The number of pieces served for the meal 

 of each larva interests us more than the 

 quality. In the cells of E. Amadei I find 

 sometimes five caterpillars and sometimes 

 ten, which means a difference of a hundred 

 per cent in the quantity of the food, for the 

 pieces are of exactly the same size in both 

 cases. Why this unequal supply, which 

 gives a double portion to one larva and a 

 single portion to another? The consumers 

 have the same appetite: what one nurseling 

 demands a second must demand, unless 

 there be here a menu differing according to 

 the sexes. In the perfect stage, the males 

 are smaller than the females, are hardly 

 16 



