88 
Psyche 
[June 
relationship between the masarids of Australia, South 
Africa, and South America respectively. This group evi- 
dently gives no support to the partisans of land connections 
between these continents during late Mesozoic and Tertiary 
times. 
In view of the highly specialized modification of the 
trophi into a proboscis correlated with strictly vegetarian 
habits, one may venture the hypothesis that the Masaridinse 
represent an early attempt at evolving an anthophilous 
group of aculeate Hymenoptera, perhaps anterior to the 
evolution of the Apoidea (or bees) from a sphecoid stock. 
It may be supposed that during some former geological pe- 
riods, these wasps were a predominant group, perhaps hold- 
ing the same important position in the ecology of the pha- 
nerogams as is nowadays reserved to the bees. Their even- 
tual decline, resulting in their present-day scarcity and dis- 
continuous distribution, may have been brought about by the 
rising competition of the Apoidea, whose branched hairs 
and highly efficient collecting apparatus gave them con- 
siderable advantage as pollen gatherers and feeders over 
the masarid wasps. 
