The True Flies 



60 First joint of the posterior tarsi slender, longer than the 

 second joint Family Agromy^idce. 



First joint greatly dilated, shorter than the second 



Family Borboridce. 



Sub-order EPROBOSCIDEA Latr. 



6 1 Head greatly depressed, projecting forward or downward, 

 body usually depressed; living on mammals (except 

 bats), birds, or honey bees Family Hippoboscidce. 



Head rounded, projecting backward upside down over the 

 thorax, body usually nearly cylindrical; living upon bats 

 Family Nycteribiidce. 



93 



