| ROBBER FLIES (ASILIDAE) | | |
| Asilinae | | |
| Asilus sericeus | Fairly common, preys mainly on Lepidoptera. |
| Efferia aestuans | Widespread and common, the most frequently reported robberfly on Martha's Vineyard. |
| Efferia albibarbis | In sandy areas, mainly beaches. |
| Machimus sadyates | Common late-season generalist. |
| Machimus novaescotiae | Apparently rare. |
| Neoitamus flavofemoratus | Uncommon; two records, both June. |
| Neomochtherus sp. | Apparently scarce; two iNaturalist records, likely representing two different species. |
| Proctacanthus brevipennis | One record. |
| Proctacanthus philadelphicus | Status unclear due to ID difficulties, but probably fairly common. Often preys on Hymenoptera. |
| Brachyrhopalinae | | |
| Cyrtopogon falto | Uncommon |
| Cyrtopogon marginalis | Uncommon; mostly in sandplain habitats. |
| Holopogon sp. | Only two records, but possibly overlooked. |
| Dasypogoninae | | |
| Taracticus octopunctatus | Uncommon. |
| Dioctriinae | | |
| Stripe-legged Robberfly | Dioctria hyalipennis | Fairly common, most records from June. |
| Laphriinae | | |
| Atomosia puella | One record, presumably uncommon. |
| Complex Laphria canis | Apparently scarce; one record. |
| Laphria champlainii | Local, strongly associated with scrub oak habitat. |
| Laphria grossa | One record. |
| Laphria thoracica | Uncommon. |
| Leptogastrinae | | |
| Leptogaster sp. | Uncommon. |
| Ommatiinae | | |
| Ommatius tibialis | Fairly common |
| Stichopogoninae | | |
| Three-banded Robber Fly | Stichopogon trifasciatus | Uncommon; sandy areas, mainly beaches. |
| BEE FLIES (BOMBYLIIDAE) | | |
| Anthracinae | | |
| Anthrax albofasciatus | One Record. |
| Black Bee Fly | Anthrax georgicus | Fairly common in sandy habitat. |
| Exoprosopa fasciata | Uncommon. |
| Sinuous Bee Fly | Hemipenthes sinuosa | Uncommon. |
| Villa lateralis sp. | Genus-level observations of Villa are fairly common; many may be referable to this species. |
| Tiger Bee Fly | Xenox tigrinus | Common and conspicuous, often in settled areas. Nest parasite of the carpenter bee Xylocopa virginica. |
| Bombyliinae | | |
| Greater Bee Fly | Bombylius major | Common early-season species, mostly mid-April to mid-May. |
| Bombylius mexicanus | Uncommon. |
| Sparnopolius confusus | Uncommon. |
| Toxophorinae | | |
| Geron calvus | Scarce, two records. |
| Systropus macer | Uncommon; late summer, mimic of Ammophila wasps. |
| STILETTO FLIES (THEREVIDAE) | | |
| Therevinae | | |
| Brachylinga morata | One record. |
| Cerocatus sp. | One record. |
| Ozodiceromyia argentata | Uncommon. |
| Tabuda varia | Fairly common in sandplain habitats. |