Hippoboscidae

Forest fly Hippobosca equina, copyright Janswart.

Belongs within: Calyptratae.
Contains: Streblidae.

The Hippoboscidae, louse flies, are a group of flattened, blood-sucking flies that live as parasites of birds and large mammals. Wings may be fully developed and used for flight or reduced and non-functional. In the keds of the genus Melophagus, the wings are reduced to small tubercles on the side of the thorax and the halteres are absent (Wood 2010). Keds form part of the subfamily Lipopteninae, mostly parasitic on artiodactyls, which are characterised by fairly dense, almost entirely spiniform setae on the ventral surface of the thorax (Maa & Peterson 1987).

Characters (from Maa & Peterson 1987): Robust more or less dorsoventrally flattened flies, 1.5–12.0 mm long, usually dull with variable and poorly defined pale markings, and richly setose. Antenna and mouthparts highly specialized. Wing usually fully developed, rarely reduced or absent. Abdomen, particularly in female, mainly membranous. Aedeagus and gonopods of male simple, retracted into abdomen when at rest. Larva completing development in uterus of female. Head prognathous, rather broad and moderately flattened, with mouthparts displaced anteriorly so head is somewhat triangular in profile, and with its upper surface horizontal or descending forward; bristling light to moderate. Eyes separated in both sexes; eye large, usually horizontally elongate, rarely reduced, bare; ocelli often well-developed but sometimes vestigial or absent. Vertex well-developed, bearing ocellar triangle; inner vertical bristles long; outer vertical bristles absent; orbital bristles few to numerous. Frons large and well-developed, almost always with a soft wrinkled membranous median frontal vitta, sometimes bearing interfrontal setae or bristles, and with lateral sclerotised fronto-orbital plates that sometimes bear fronto-orbital setae or bristles; ptilinal fissure conspicuous; lunule usually large and conspicuous, shiny and bare, with a variably distinct suture separating it from face or sometimes fusing anteriorly, often imperceptibly, with facial sclerite. Face variable in size, sometimes produced at each anterolateral corner, and sometimes uniting with parafacial to surround and isolate antennal socket; face bare, but ridge enclosing anteroventral margin of antennal socket often bristled. Clypeus greatly reduced, membranous to lightly sclerotised. Antenna highly modified, immovable or with movement greatly restricted, lying in a deep single antennal socket or in paired sockets; scape usually small but usually recognizable, sometimes completely separated from lunule by a distinct suture and bearing stout setae, or more or less fused with lunule but recognisable by presence of one or more stout setae, or completely fused with lunule without external indication of its presence; pedicel constituting the largest of the antennal segments and enclosing the first flagellomere, rounded in shape, and with or without an antennal appendage; this appendage dorsally flattened, leaf-like, bearing numerous setae and bristles; dorsolateral longitudinal suture on pedicel usually distinct; arista protruding from pedicel, spatulate, bipectinate, or variously branching. Palpus one-segmented, nearly always well-developed, rarely reduced or vestigial, compressed laterally but with concave inner surface serving as sheath for labium, and usually heavily bristled; labium bulbous basally, with the remainder needlelike, and terminating in tiny labella with a double crown of prestomal teeth; labium retractable when not in use and concealed in subcranial cavity and by palpi. Thorax flattened, about one-third or less as high as width of scutum; lateral surface vertically flattened or concave, with dorsal margin variably folded dorsomedially so that part of upper lateral surface is dorsal in position; ventral surface or katepisternum broadened and flattened, widely separating each pair of coxae. Antepronotum reduced, more or less concealed; postpronotal lobes variably developed but sometimes with anterolateral angle strongly produced lobe-like on each side of base of head, and sometimes enclosing anterior spiracle; this spiracle usually conspicuous and more or less dorsally situated. Scutum large, divided behind midlength into a larger presutural areaand a smaller postsutural area by a transverse suture; transverse suture sometimes complete, or variably incomplete to faintly indicated laterally; median scutal suture also present, variably distinct and variably complete, sometimes meeting or even continuing posteriorly beyond transverse suture to near scutellum; bristling highly variable, with postpronotal, notopleural, supra-alar, postalar, pre- and post-sutural dorsocentral, and pre- and post-sutural acrostichal bristles appearing in various combinations and numbers, or sometimes absent. Scutellum usually large and well-developed, although sometimes small, varying from subtriangular to rectangular with parallel anterior and posterior margins; apical and discal bristles and setae few to numerous, rarely absent. Laterotergite of postnotum either gently or strongly raised as a convex process, and in turn sometimes bearing a digitiform process. Wing fully developed but sometimes falling off soon after emergence, reduced, or very rarely represented by a solid subcylindrical knob; membrane of wing often with microtrichia in varying patterns. Veins usually crowded toward anterior margin; distal part of posterior veins sometimes weak and not reaching wing margin; venation simple and nearly complete, or variously reduced; crossvein bm-cu absent or very faintly indicated. Alula, calypter, and halter present, rarely reduced or absent. Legs robust, moderately short, often strongly bristled; coxae short but greatly swollen, femora variously swollen, tibiae less swollen to somewhat flattened, and hind tibia sometimes with a slight swelling or depression in basal half. Tarsomeres short; first tarsomere sometimes more elongate than next three tarsomeres combined; apical tarsomere the largest. Tibiae and tarsi often with a longitudinal series of sensory pores and setae. Claws stout, simple or bifid, and with a prominent flattened heel-like base; empodia hairy or feathery; pulvilli paired and pad-like, often soft and elongate; claws, pulvilli, and apical lobes of certain tarsomeres of same leg sometimes aymmetric. Abdomen extensively membranous, particularly in female, with seven pairs of spiracles in both sexes; tergite 1 often represented by a pair of variably developed lateral plates in which or in front of which are located anterior spiracles on each side; these plates either free, or partly or entirely fused with tergite 2, thus forming syntergite 1+2; tergite 2 large, sometimes free but usually fused with tergite 1, sometimes with margins projecting somewhat ventrally and more often posteriorly as short to moderately long blunt or pointed processes; one or more paired or unpaired tergites sometimes following syntergite 1+2, identifiable by position of spiracles; tergite 6 and tergite 7 most frequently consisting of plates; tergite 8 membranous in female. Sternite 1 rarely absent, usually represented by heavily sclerotised plate with hind margin either transverse, convex, or concave, and sometimes with posterolateral margins projecting arm-like posteriorly; remaining ventral surface of abdomen membranous, often densely setose or bristled, sometimes with narrow bare strips denoting segmental limits; female sometimes with sternites 6 and 7 present as small variously sclerotised plates bearing one to several setae or bristles, with sternite 6 usually smaller and weaker than sternite 7; male sometimes with a pair of small or large sclerotised plates representing sternite 5, but sternites 6 and 7 membranous. Terminalia of female simple, but variable. Sometimes a tiny dorsomedial sclerite, probably representing the epiproct, present just anterior to and closely associated with cerci. Cerci sometimes present as small to moderately large flap-like setose structures or as slender setose ring-like structures, and sometimes separated dorsomedially by a tiny epiproct or fused dorsomedially; cerci not fused ventrally, but closely associated with hypoproct so that they appear to be fused. Sternite 8 often absent, but sometimes present as a U-shaped or subtriangular-shaped or transverse barlike sclerite just anterior to genital opening. Hypoproct small to large, simple to complex, membranous or sclerotised, and sometimes at least partly retractable internally; hypoproct usually consisting of a single structure, but in more complex forms seemingly composed of two or three united pieces with or without pale lines of apparent demarcation, and often with one or two variably developed raised ridges or rims. Two or three spermathecae present. Terminalia of male simple, retracted into abdomen when at rest and exserted for mating. Syntergosternite 7+8 variably developed from a slender weakly sclerotised half-ringlike sclerite to a broader saddle-like sclerite that may be variably excavated or emarginate dorsomedially along either anterior or posterior margin or both. Epandrium a narrow ring-like setose sclerite that may be continuous or narrowly separated dorsomedially into two halves, with ventral margin of each side often widening; surstyli sometimes present, in form of small setose lateroventral plates or larger lobes or flaps articulating with ventral margins of epandrium. Cerci fused, apparent externally as a flattened sclerotised rod-like or platelike sclerite; this sclerite setose distally, continuing anteriorly into genital pouch, and situated ventromedial to and articulating with epandrium; cerci sometimes greatly reduced and sometimes very lightly sclerotised or membranous, sometimes apparently absent. Sternite l0 sometimes present in form of short rod extending ventrally from anterior (internal) base of cerci to dorsal margin of base of aedeagus and gonopods. Hypandrium a relatively large trough-like heavily sclerotised plate fused with gonopods; gonopods elongate, subtriangular to digitiform, tubular, extending posteriorly on each side of aedeagus and exserted at same time as aedeagus during copulation, and usually beset with several microsetae and tubular sense organs; aedeagus rather large, sometimes rodlike and slender, or broader and cone-shaped with sclerotised dorsal rods and sometimes sclerotised laterally; aedeagal membrane usually with fine setae or spinules and sometimes with stouter spines; aedeagal apodeme well-developed, flattened and platelike, articulating with hypandrium; hypandrium and aedeagal apodeme enlarging and extending anteriorly with age of adult; aedeagal apodeme somewhat rod-like in newly emerged males but becoming sometimes more flattened and triangular in outline in old males. Egg elongate cylindrical, tapering anteriorly, blunter posteriorly, very slightly concave dorsally. Micropylar pores lying in funnel-shaped depression at anterior end. Larva with three instars developed. First instar maggot-like, with faint traces of segmentation, and with eight pairs (two thoracic, six abdominal) of rudimentary lateral spiracles; a nipple-like projection bearing mouth and a pair of minute papillae present anteriorly; anus and a pair of spiracles evident posteriorly, lying together on a spiracular plate; cephalopharyngeal skeleton and mandibles absent. Second instar similar to first, but with a plumper ellipsoidal shape. Third instar barrel-like; a transverse circular seam and a longitudinal semicircular seam (along which the adult breaks open and emerges from puparium) evident anteriorly, as well as functionless apertures of thoracic spiracles; a pair of plates or lobes present posteriorly, each bearing three spiracles or three curved series of spiracular pores, in addition to an anus; lateral abdominal spiracles completely lost. Puparium similar to third-instar larva, but with cuticle much more hardened and darkened. Circular and semicircular seams slightly more significant; polypneustic lobes at posterior end more protruding.

<==Hippoboscidae [Coriaceae, Eproboscidea, Olfersiini]
    |  i. s.: Stenepteryx hirundinis A71
    |         Ornithoica [Ornithoicinae] W10
    |           `--O. vicina W10
    |         Allobosca [Alloboscinae] W10
    |           `--A. crassipes W10
    |--Ornithomyinae [Ornithomyini] MP87
    |    |  i. s.: Austrolfersia CM91
    |    |         Myophthiria [=Myiophthiria] MP87
    |    |           `--M. fimbriata W10
    |    |         Stilbometopa impressa MP87, W10
    |    |         Olfersia MP87
    |    |           |--O. bisulcata W10
    |    |           |--O. fumipennis W10
    |    |           `--O. spinifera W10
    |    |         Icosta MP87
    |    |           |--I. albipennis W10
    |    |           |--I. americana W10
    |    |           |--I. ardeae MP87
    |    |           `--I. hirsuta MP87
    |    |         Microlynchia pusilla MP87, W10
    |    |--Ornithoctona erythrocephala KP10, W10
    |    `--+--Crataerina KP10
    |       |    |--C. hirundinis WT11
    |       |    |--C. pallida KP10
    |       |    `--C. seguyi W10
    |       `--Ornithomya Latreille 1802 KP10, L02 [=Ornithomyia MP87]
    |            |  i. s.: O. rottensis MP87
    |            |--O. biloba KP10
    |            `--+--+--O. fringillina KP10
    |               |  `--O. hirundini KP10
    |               `--+--*O. avicularia (Linnaeus 1758) L02, KP10, L58 [=Hippobosca avicularia L02]
    |                  `--+--O. anchineura KP10
    |                     `--O. chloropus KP10 [incl. O. lagopodis A71]
    `--+--+--+--Streblidae KP10
       |  |  `--Ortholfersia [Ortholfersiinae] KP10
       |  |       |--O. macleayi CM91
       |  |       `--O. minuta KP10
       |  `--Hippobosca Linnaeus 1758 KP10, L58 [Hippoboscinae]
       |       |--H. camelina A71
       |       |--H. capensis A71
       |       |--H. equina Linnaeus 1758 L58
       |       |--H. fulva A71
       |       |--H. hirsuta A71
       |       |--H. hirundinis Linnaeus 1758 L58
       |       |--H. longipennis MP87
       |       |--H. martinaglia A71
       |       |--H. rufipes Olfers 1816 R01 [incl. H. maculata R01, H. variegata A71, H. wahlenbergiana R01]
       |       |--H. sitiens Boisduval 1835 B35
       |       `--H. struthiornis A71
       `--+--Pseudolynchia KP10
          |    |--P. brunnea W10
          |    `--P. canariensis W10
          `--Lipopteninae [Melophaginae] MP87
               |--Neolipoptena ferrisi MP87, W10
               `--Lipoptena KP10
                    |--+--L. depressa KP10
                    |  |    |--L. d. depressa MP87
                    |  |    `--L. d. pacifica MP87
                    |  `--L. mazamae KP10
                    `--+--L. cervi KP10
                       `--Melophagus Latreille 1802 KP10, L02
                            |--*M. ovinus (Linnaeus 1758) L02, L58 [=Hippobosca ovina L02]
                            `--M. rupicaprinus A71

*Type species of generic name indicated

REFERENCES

[A71] Askew, R. R. 1971. Parasitic Insects. Heinemann Educational Books: London.

[B35] Boisduval, J. B. 1835. Voyage de Découvertes de l’Astrolabe. Exécuté par ordre du Roi, pendant les années 1826–1827–1828–1829, sous le commandement de M. J. Dumont d'Urville. Faune entomologique de l'océan Pacifique, avec l'illustration des insectes nouveaux recueillis pendant le voyage vol. 2. Coléoptères et autres ordres. J. Tastu: Paris.

[CM91] Colless, D. H., & D. K. McAlpine. 1991. Diptera (flies). In: CSIRO. The Insects of Australia: A textbook for students and research workers 2^nd ed. vol. 2 pp. 717–786. Melbourne University Press: Carlton (Victoria).

[KP10] Kutty, S. N., T. Pape, B. M. Wiegmann & R. Meier. 2010. Molecular phylogeny of the Calyptratae (Diptera: Cyclorrhapha) with an emphasis on the superfamily Oestroidea and the position of Mystacinobiidae and McAlpine's fly. Systematic Entomology 35: 614–635.

[L02] Latreille, P. A. 1802. Histoire Naturelle, générale et particulière des crustacés et des insectes vol. 3. Familles naturelles des genres. F. Dufart: Paris.

[L58] Linnaeus, C. 1758. Systema Naturae per Regna Tria Naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Laurentii Salvii: Holmiae.

[MP87] Maa, T. C., & B. V. Peterson. 1987. Hippoboscidae. In: McAlpine, J. F. (ed.) Manual of Nearctic Diptera vol. 2 pp. 1271–1281. Research Branch, Agriculture Canada.

[R01] Ricardo, G. 1901. Notes on Diptera from South Africa (concluded). Annals and Magazine of Natural History, series 7, 7: 89–110.

[WT11] Wiegmann, B. M., M. D. Trautwein, I. S. Winkler, N. B. Barr, J.-W. Kim, C. Lambkin, M. A. Bertone, B. K. Cassel, K. M. Bayless, A. M. Heimberg, B. M. Wheeler, K. J. Peterson, T. Pape, B. J. Sinclair, J. H. Skevington, V. Blagoderov, J. Caravas, S. N. Kutty, U. Schmidt-Ott, G. E. Kampmeier, F. C. Thompson, D. A. Grimaldi, A. T. Beckenbach, G. W. Courtney, M. Friedrich, R. Meier & D. K. Yeates. 2011. Episodic radiations in the fly tree of life. Proceedings of the National Academy of Sciences of the USA 108 (14): 5690–5695.

[W10] Wood, D. M. 2010. Hippoboscidae (louse flies). In: Brown, B. V., A. Borkent, J. M. Cumming, D. M. Wood, N. E. Woodley & M. A. Zumbado (eds) Manual of Central American Diptera vol. 2 pp. 1241–1248. NRC Research Press: Ottawa.

Last updated: 9 July 2021.