Is it a fly or a wasp?

Fusco Brothers by J.C. Duffy
Wasps have 2 pairs of wings. Therefore, the fairy flies are wasps (order Hymenoptera).



Flies have 1 pair of wings. Therefore, the bee flies are flies (order Diptera), even though bees are hymenopterans.

Both drawings and information are from How to know the insects by H. E. Jaques (1947).