By Neal L. Evenhuis Species of Gasterophilidae, commonly known as horse bot flies, are represented in these regions by introduced Old World cosmopolitan species whose distributions coincide with those of their hosts. Larvae of gasterophilids, as with oestrids, are encountered more frequently than adults. They develop in the digestive tracts of their hosts and are passed out in feces, where pupariation occurs.
Adults have vestigial mouthparts and, consequentially, a short flight period.
Invalid emend. of Gasterophilus .