CH. V] WASPS 151 



indifferently. Males, however, are here always in far 

 smaller proportion than in the ordinary small cells. 

 Finally the full sized "royal" cells contain invariably 

 (provided the " queen " be healthy) females only, and these 

 as already explained are made into "queens" by liberal diet. 

 We cannot do better than quote the words of Paul 

 Marchal who has devoted much attention to this matter : 

 " We will admit that after an exclusive and uninterrupted 



deposit of worker-eggs at first, , the reflex, which 



causes the contraction of the seminal receptacle when 

 each egg is being laid, no longer acts with the same 

 regularity. The eggs can then be laid without being 

 fertilised. Hence the almost sudden appearance of the 

 males depends upon the relative inactivity of the seminal 

 receptacle. It is then that the workers build the large 

 cells and thus give the 'queen' a choice between two 

 different kinds of cell. The large cells, at the end of the 

 season, have the property of stimulating the ' queen/ 

 while she in certain instances seems to visit them with 

 marked preference. We may admit that on these large 

 cells she will concentrate all her energy and that in 

 consequence she will only lay in them fertilised (female) 

 eggs ; or again, that she will only lay in them when her 

 seminal receptacle is ready to contract. On the other 

 hand, when she is on the small cells she will lay carelessly 

 and at random, whatever be the state of her receptacle : 

 then according as the receptacle responds or not, the 

 deposit of eggs will produce, in the former case, groups 

 of females, and in the latter, groups of males 1 ." 



1 Paul Marchal, Arch, de Zool. Exp. et Gen. (3) iv. 1896. 



