The species of the family Tetrastichinae are found in almost any type of terrestrial habitat and have a worldwide distribution, except Antarctica.

Endoparasitism is more frequent than ectoparasitiusm and taxa of either parasitic type may be gregarious or solitary.

In other genera it is the ecological or behavioural traits of the host which are important, the Minotetrastichus species parasitise leaf miners whether these are Coleoptera, Hymenoptera or Lepidoptera; while other groups target galls irrespective of the nature of the gall former.

Another reason for the scarcity of males is that in some taxa (e.g. Melittobia) they have been observed to stay within the host pupa on emergence and aggressively attack and kill each other until only a few survive.

de V. Graham split this large genus into a number of smaller, more natural groupings, fifteen of which were named as new genera.