500 



of the seed coat. Upon a careful study of the emergence of 

 Bruchus pruininus it was found that in this sjoecies the pro- 

 cedure is as follows, the observations being made on it breeding 

 in the seeds of Leucaena glauca. In this plant the seeds have a 

 thin, albuminous endosperm which the larva gnaws away more 

 or less on either side of the seed in the latter part of its 

 feeding period, and this is particularly the case just opposite 

 the place where it finally places its head and which will be 

 in contact with the future mandibles of the adult. Here ap- 

 pears a definite circular patch where the albumen is entirely 

 eaten away but if this be examined during the pupal period 

 it will be seen that the circular cut has not yet been made 

 which permits the separation of the bit covering the emergence 

 hole. This is undoubtedly made by the adult just before emer- 

 gence by revolving in its pupal cell. 



