Key to Asilidae subfamily taxa sensu Dikow (2009)

This interactive, matrix-based identification key is provided to place all Asilidae genera in the revised, phylogenetic classification proposed by Dikow (2009). This newly revised classification recognises 14 subfamily taxa based on already published family-group names summarised in Sabrosky (1999) and Dikow (2004). The status of some of the taxa is revised, but no new family-group names have been proposed.

The 14 taxa are: Asilinae, Bathypogoninae, Brachyrhopalinae, Dasypogoninae, Dioctriinae, Laphriinae, Leptogastrinae, Ommatiinae, Phellinae, Stenopogoninae, Stichopogoninae, Tillobromatinae, Trigonomiminae, and Willistonininae. Details about revised, phylogenetic classification.

The phylogenetic analysis, which is the basis for this classification, was published as Dikow, T. 2009. Phylogeny of Asilidae inferred from morphological characters of imagines (Insecta: Diptera: Brachycera: Asiloidea). Bulletin of the American Museum of Natural History 319: 1–174. Download a free PDF from the AMNH library.

The characters for this key are taken from Table 7, are described below, and are illustrated with photographs and line drawings in the interactive key, which are partly taken from Dikow (2009). Photographs of Asilidae were kindly provided by Michael Thomas, Giff Beaton, Fritz Geller-Grimm, Riley Nelson, Eileen Collins, and Robert Copeland.

Start the key in a new tab/window here.
Please also read below for how to use the key, system requirements, description of the 24 characters used in the identification key (taken from the character matrix in Dikow (2009)), and the table with the information regarding the proximal tarsomeres, a character which might help in placing genera in the revised classification as well. For detailed information about the revised, phylogenetic classification implemented in this identification key see.

Using the key
As this is an interactive identification key, you can select any character to start with.
Select a character from the list in the upper left → use the triangle to open the character choices → enter the state. Taxa still to be identified remain in the upper right and taxa discarded are moved to the lower right.
Use the ‘Best’ and ‘Next Best’ buttons (shown below) to select the best possible character to identify the remaining taxa.
Use the ‘Character’ and ‘Taxa’ thumbnail buttons (shown below) to hide or expand the previews of the images.

System requirements
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Test your Java version.
Download the latest, freely-available Java version.

Description of 24 characters used in the identification key

Maxillary stipites #14 – The stipites of the maxilla are two separated sclerites bearing the maxillary palpi in Diptera (McAlpine 1981). In the Asilidae, the stipites are large plate-like sclerites at the base of the proboscis that can be fused medially or divided medially.
– Undivided: all Dasypogoninae, Leptogastrinae, Ommatiinae, Tillobromatinae, and Trigonomiminae.
– Divided: all Bathypogoninae and Stichopogoninae.

Position of tentorial pits #44 – Papavero (1973) used the development of the anterior tentorial pits (referred to as “deep, mediogenal grooves”), as a diagnostic character for the Trigonomiminae. In most Asilidae species, the tentorial pits are small, slit-like and inconspicuously positioned more or less ventrally.
– Well-developed, conspicuous and positioned antero-medially: all Trigonomiminae.

Size of anterior-median ommatidia #46 – As early as Walker (1851), dipterists realised that the median ommatidia of the flattened compound eyes of an assassin fly are often enlarged. The majority of Asilidae species possess larger ommatidia medially.
– same size: all Bathypogoninae, Phellinae, and Stenopogoninae.
– different size: all Leptogastrinae, Ommatiinae, Trigonomiminae, and Willistonininae.

Shape of frons #48 – The frons is usually parallel-sided as wide at the ventral margin as at the level of antennal insertion in Asilidae.
– markedly and suddenly diverging: all Stichopogoninae and a few Willistonininae.

Macrosetae on lateral frons #49 – Asilidae usually possess setae on the lateral margin of the frons dorsal to the antennal insertions. These setae can be particularly well developed and form strong macrosetae.
– only regular setae: all Brachyrhopalinae, Leptogastrinae, Ommatiinae, Tillobromatinae, Trigonomiminae, and Willistonininae.
– macrosetae and regular setae: all Bathypogoninae and representatives of all remaining subfamily taxa.

Postpedicel shape #54 – The shape of the postpedicel varies considerably in Asilidae.
– cylindrical: throughout Asilidae
– never cylindrical: all Brachyrhopalinae, Ommatiinae, and Willistonininae.

Setae anteriorly on antennal stylus #59 – Hardy (1927), in erecting the tribe Ommatiini, pointed out the setose antennae of species of Ommatius and related genera.
– setae present: all Ommatiinae.
– setae absent: all remaining taxa.
Note: Oligopogon possesses setae on all surfaces of the stylus.

Lateral eye margin strongly sinuate #64 – The majority of Asilidae have a more or less oval-shaped compound eye in lateral view. In most Asilinae and a few other species the ventral quarter is angled anteriorly and the ventral part of the eye is much narrower than the dorsal half, but this state is not coded here.
– eye margin strongly sinuate: all Stichopogoninae.
– eye margin not strongly sinuate: all remaining taxa.

Median occipital sclerite setae #65 – The median occipital sclerite is situated ventral to the vertex and between the compound eyes and often entirely fused to the occiput (McAlpine 1981). In Dasypogoninae, the sclerite is relatively easy to distinguish and in most instances, more than two macrosetae are situated on it.
– setae absent: all Asilinae, Bathypogoninae, Brachyrhopalinae, Dioctriinae, Laphriinae, Leptogastrinae, Ommatiinae, Phellinae, and Trigonomiminae.
– setae present: most Dasypogoninae as well as some Stenopogoninae, Tillobromatinae, and Willistonininae.

Prosternum flange dorsally #75 – The dorsal (anterior) margin of the prosternum is usually not particularly pronounced, but in a few species a distinct dorsal flange-like projection is evident.
– present: all Laphriinae and Trigonomiminae, most Leptogastrinae and Stichopogoninae as well as some Dioctriinae and Tillobromatinae.
– absent: all Asilinae, Bathypogoninae, Brachyrhopalinae, Dasypogoninae, Ommatiinae, Phellinae, Stenopogoninae, and Willistonininae.

Metkatepisternum visible (ventral) #100 – Yeates & Irwin (1996) postulated the large metkatepisternum (referred to as “metepisternum”) as an autapomorphy for a subordinate taxon of Mydidae. In Asilidae, the metkatepisternum is usually small and not visible between the mes- and metathoracic coxae.
– visible: many Laphriinae, some Dasypogoninae and Acronyches (Leptogastrinae).

Postmetacoxal bridge sclerotised #102 – Several authors, e.g., Hull 1962, Papavero 1973, have emphasised the development of sclerotization in the postmetacoxal area in Asilidae. Most Asilidae possess an entirely membranous postmetacoxal area with a straight lateral margin.
– complete postmetaxcoxal bridge: all Ommatiinae, most Atomosiini (Laphriinae), and a few Brachyrhopalinae and Trigonomiminae.
Note: A partly developed postmetacoxal bridge in which the lateral sclerites fold medially, but where the median area is still membranous to a large extent or a median suture is still visible dividing the two halves is to be considered as an unsclerotised postmetacoxal bridge in the key.

Dorso-ventrally flattened setae on legs #103 – Setae on all legs are usually circular in cross section in Asilidae, but some Willistonininae possess dorso-ventrally flattened setae as well as circular setae on the legs.

Straight spine on prothoracic tibia #106 – One of the most obvious characters used in classifications on Asilidae has been the development of spurs or spines on the prothoracic tibiae, e.g., Hermann 1912, 1920, Hull 1962, Papavero 1973, Oldroyd 1974, and Hermann (1912) based an entire taxon on the presence of projections, i.e., Acanthocneminae (unavailable name: Sabrosky 1999, Dikow 2004). The majority of Asilidae species lack any projections on the prothoracic tibiae with the exception of straight macrosetae or setae.
The large spine found in Molobratia teutonus is easy to observe, but the smaller, S-shaped spur in, e.g., Leptarthrus brevirostris, is difficult to see and to distinguish from the surrounding macrosetae. A detailed examination of the different tibial projections reveals that the large spines are always originating on the postero-ventral surface whereas the small, S-shaped spurs originate on the antero-ventral surface of the prothoracic tibiae. Hull (1962) and Oldroyd (1974) recognised the different shapes of the projections, but not their different origin on the prothoracic tibiae.
– straight spine present: most Dasypogoninae and some Australian Brachyrhopalinae.

Blunt protuberance anteriorly on metathoracic coxa #113 – Cannings (2002) observed the blunt protuberance on the anterior surface of the metathoracic coxa of some Stichopogoninae in contrast to species of Lasiopogon, and Londt (2005) based the description of the Afrotropical genus Ischiolobos (placed in Stenopogoninae sensu Papavero 1973), on the presence of a blunt protuberance on the metathoracic coxa. The majority of Asilidae do not possess any protuberance on the metathoracic coxae.
– blunt protuberance: all Bathypogoninae as well as some Brachyrhopalinae, Stenopogoninae, Stichopogoninae, Tillobromatinae, and Willistonininae.
– peglike, pointed protuberance: some Dioctriinae.

Pulvilli #123 – Martin (1968) observed that the pulvilli are absent in all Leptogastrinae and a few other species of Asilidae and concluded that the lack of pulvilli is a plesiomorphic character.
– pulvilli absent: all Leptogastrinae as well as some Willistonininae.

Alula reduced in size #130 – Karl (1959) and Martin (1968) discussed the reduction of the alula as an autapomorphy of the Leptogastrinae in contrast to most other species of Asilidae, which have a well-developed alula.
– alula reduced: all Leptogastrinae and Stichopogoninae as well as some Brachyrhopalinae, Dasypogoninae, Dioctriinae, Laphriinae, Trigonomiminae, and Willistonininae.

Cell r1 closed #131 – Hull (1962), Papavero (1973), and subsequent authors widely used the development of cell r1 for separating taxa of Asilidae, but highlighted the fact that this character has to be used with caution because a closed cell r1 is supposed to have arisen several times independently. An open cell r1, in which veins R1 and R2+3 reach the wing margin separately, is present in most Asilidae.
– cell r1 closed: all Asilinae and Ommatiinae, most Laphriinae, as well as some Dasypogoninae.

Cell cup closed #136 – Karl (1959) used the open or closed cell cup in his phylogeny of Asilidae.
– cell cup closed: all Asilinae, Bathypogoninae, Laphriinae, Ommatiinae, Phellinae, Stichopogoninae, as well as many Dasypogoninae, Stenopogoninae, Trigonomiminae, and Willistonininae.

Vein R2+3 arching 90 degrees anteriorly #142 – Wood (1981) and later authors used the sharply arching vein R2+3 as a diagnostic feature to separate genera of Laphriinae from Laphystia and relatives (Laphystiinae sensu Papavero 1973). Most Asilidae exhibit a relatively straight vein R2+3.
– vein R2+3 arching anteriorly: all Bathypogoninae, some Laphriinae, Stenopogoninae, Tillobromatinae, and Willistonininae.

Vein R4 sinuate distally #144 – Papavero (1973) established the strongly sinuate vein R4 as the defining characteristic to separate Laphriinae and a number of genera related to Laphystia (Laphystiinae sensu Papavero 1973). Most species of Asilidae exhibit a relatively straight vein R4.
– vein R4 sinuate distally: all Bathypogoninae, some Laphriinae and Stenopogoninae.

Short stump vein on R4 #146 – The wing venation in Asilidae is relatively straightforward and simple compared to, for example, Mydidae or Nemestrinidae. The short stump vein present at the base of R4 just after departing from the common R4+5 in a few taxa is, however, an interesting case of the development of an additional vein not commonly present in other taxa. Most Asilidae species lack any sign of the stump vein on R4.
– short sump vein present: all Phellinae, some Asilinae and Willistonininae.

Adominal tergite 2 (T2) more than twice as long as wide #153 – Martin (1968) established the elongated second abdominal tergite in Leptogastrinae species as an autapomorphy for this taxon and it has since been used in identification keys by several authors, e.g., Wood 1981.
– T2 more than twice as long as wide: all Leptogastrinae.

Abdominal segments comprising ovipositor #167 – The specialised abdominal segments that are associated with the oviposition of eggs are generally referred to as the ovipositor. The ovipositor of Diptera is not homologous to the “true” ovipositor found in other Endopterygota (e.g., Mickoleit 1973, McAlpine 1981). In general, the ovipositor comprises segments 8 and 9.
– ovipositor segment 7 and following: all Phellinae, some Laphriinae, Leptarthrus (Brachyrhopalinae).

Additional, informative characters
The table below (Table 3 of Dikow 2009) indicates the respective lengths of the proximal tarsomeres (characters 120–122) that appear to be diagnostic for at least some subfamily taxa, and so can be informative in placing genera as well, e.g., Dasypogoninae with proximal tarsomeres always longer than the two following tarsomeres combined and Stichopogoninae with proximal tarsomeres always shorter than (or equal in length to) the two following tarsomeres combined.
Note that a species exhibiting state (0) on the prothoracic leg might not exhibit the same state on another leg, for example, and the columns are just counts of species; number in parentheses following the taxon name equals number of species of the taxon included in Dikow (2009).

**Length of proximal tarsomeres in relation to two following tarsomeres combined.**
**state 0** = shorter or equal to the length of two following tarsomeres combined
**state 1** = longer than two following tarsomeres combined
Taxon	prothoracic state 0	prothoracic state 1	mesothoracic state 0	mesothoracic state 1	metathoracic state 0	metathoracic state 1
Asilinae (32)	21	11	20	12	4	28
Bathypogoninae (1)	–	1	–	1	–	1
Brachyrhopalinae (18)	2	16	13	5	all	–
Dasypogoninae (16)	–	all	–	all	–	all
Dioctriinae (9)	8	1	7	2	1	8
Laphriinae (29)	13	16	13	16	2	27
Leptogastrinae (7)	2	5	3	4	3	4
Ommatiinae (7)	all	–	4	3	–	all
Phellinae (2)	–	all	–	all	–	all
Stenopogoninae (13)	2	11	–	all	–	all
Stichopogoninae (7)	all	–	all	–	all	–
Tillobromatinae (3)	–	all	2	1	–	all
Trigonomiminae (7)	6	1	6	1	4	3
Willistonininae (5)	all	–	all	–	2	3