Mesostigmata

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Taxonomy

updated 2025

Diagnostic characters

• Fixed chelachela:
  a pincer, as in a pseudoscorpion's distal pedipalpal segments.
  with membranous lobe replacing pilus dentilispilus dentilis:
  (pl. pili dentilis) a seta-like or membranous sensory organ inserted ventrolaterally on the fixed digit of the chelicera of many Mesostigmata.
  
• Movable chelachela:
  a pincer, as in a pseudoscorpion's distal pedipalpal segments.
  with ventralventral:
  relating to the lower or under side; opposed to dorsal.
  mucro near basebase:
  the usually columnar basal part of the tritosternum; sometimes expanded and rectangular or otherwise modified; the most basal part of any structure.
  
• Epigynialepigynal:
  (also epigynial) of or relating to the female genital opening or a shield protecting it.
  shield usually rounded posteriorly
• Anal shield usually bearing circum-anal setae only
• Spermathecaspermatheca:
  a structure in the female for storing sperm, typically sac-like.
  of laelapid-type but often obscure and always lacking well sclerotized cervixcervix:
  (= calyx) in phytoseioid Mesostigmata (Phytoseiidae, Blattisociidae, Otopheidomenidae, Podocinidae), a collar-like structure of the sperm access system which surrounds the base of the vesicle.
  
• Dorsaldorsal:
  relating to the upper or back side; opposed to ventral.
  shield entireentire:
  a shield or sclerite with a continuous margin without incisions.
  ; podonotalpodonotal:
  relating to the dorsal podosoma, the region of the idiosoma over the legs.
  region holotrichous or nearly so, seta z3 present; opisthonotalopisthonotal:
  dorsal opisthosoma.
  region with 18–22 pairs of setae, including most of the posteriorposterior:
  the back part of the body or towards that region in comparison, e.g., 'posterior to'.
  marginal (R) setae.
• Female usually with metasternal plates 
• Corniculicorniculus:
  (pl. corniculi) (also, external malae) a usually horn-like process (sometimes toothed, bifurcate, trifurcate, spine-like, spatulate, or membranous) on the subcapitulum of parasitiform mites that usually supports the salivary styli.  A toothed corniculus could be confused with a rutellum, a possibly homologous structure in Acariformes and Opilioacarida. Phytoseiid image is spatulate corniculus.
  stout, sometimes bifid or toothed

More about Proctolaelaps on Bee Mite ID

Similar taxa

Except for Mycolaelaps, no other Melicharinae have dorsaldorsal:
relating to the upper or back side; opposed to ventral.
shields that capture most of the R-series, but the Proctolaelaps hystrix group captures only R1–4 (R5–7 in soft cuticle) and is similar to Mucroseius, but lacks the distaldistal:
towards the free end of an appendage.
cheliceral process. Also, species of Proctogastrolaelaps have a separate ventral shieldventral shield:
in Mesostigmata, any shield or shields in the ventral region; often fused with the anal shield to form a ventrianal shield. [Back to Top]
; species of Rhinoseius, Tropicoseius, and Xanthippe has incised dorsaldorsal:
relating to the upper or back side; opposed to ventral.
shields; species of Mucroseius have macrosetae on telotarsustelotarsus:
(= acrotarsus, apicotarsus) a distal division of the tarsus.  
IV and a distaldistal:
towards the free end of an appendage.
process on the fixed digitfixed digit:
the distal extension of the middle article of the chelicera; usually bearing teeth and a distal hook and opposed to the movable digit in chelate-dentate forms, but often regressed; in Mesostigmata the fixed digit may bear the pilus dentilis.
; species of Melichares lack metasternal plates. Species of Neojordensia and Orthadenella capture the R -setae, but have a ventrianal shieldventrianal shield:
in Mesostigmata, a ventral shield bearing the anal opening, circum anal setae, and one or more pairs of ventral setae or pores (lyrifissures) [see anal shield]; maybe rather narrow or very broad and covering most of the gaster.
.

Similar taxa not in the Lucid key (see below): Orolaelaps De Leon (=Proctolaelaps)

Key to the genera of Melicharinae

1. Idiosoma narrow, dorsaldorsal:
   relating to the upper or back side; opposed to ventral.
   shield greater than twice as long as wide; leg setation strongly neotenous, genuagenu:
   (pl. genua) (= patella) the 4th leg segment, between the femur and tibia.
   I–II–III–IV with 12–7–6–7 setae, tibiaetibia:
   (pl. tibiae) the leg segment between the genu and the tarsus.
   with 11–7–6–6 setae; female lacking metasternal plates and with ventri-anal shield bearing 1–3 pairs of ventral setaeventral setae:
   in the Lindquist-Evans system used in the Mesostigmata, the ventral region has up to three longitudinal rows (Jv, Zv, Lv) with 1-5 transverse row designations.
   in addition to circumanal setaecircumanal setae:
   in Mesostigmata, the three setae (postanal and pair of peranal) setae surrounding the anal opening.
   .............................. Mycolaelaps
   - Idiosoma broader, legs not strongly neotenous, metasternal plates present or absent, only anal shield or separate anal and ventralventral:
   relating to the lower or under side; opposed to dorsal.
   shields.............................. 2

2. Female with separate ventral shieldventral shield:
   in Mesostigmata, any shield or shields in the ventral region; often fused with the anal shield to form a ventrianal shield. [Back to Top]
   bearing 4 pairs of setae between genital and anal shields; posteriorposterior:
   the back part of the body or towards that region in comparison, e.g., 'posterior to'.
   connection of peritrematalperitrematal:
   (peritrematic) of or referring to the peritreme; adjectival form of peritreme.
   shield to exopodal plate beside coxacoxa:
   the basal segment of the leg, articulating with (Parasitiformes) or fused to (Acariformes) the body wall.
   IV broad (subequal to width of stigmastigma:
   the opening to the tracheal system.
   ); corniculicorniculus:
   (pl. corniculi) (also, external malae) a usually horn-like process (sometimes toothed, bifurcate, trifurcate, spine-like, spatulate, or membranous) on the subcapitulum of parasitiform mites that usually supports the salivary styli.  A toothed corniculus could be confused with a rutellum, a possibly homologous structure in Acariformes and Opilioacarida. Phytoseiid image is spatulate corniculus.
   slender, acute; rows of deutosternal denticlesdeutosternal denticles:
   rows of small teeth-like projections (often irregular and sometimes reduced to a single tooth) running transversely across the deutosternal groove and sometimes onto the lateral faces of the subcapitulum.
   narrow, in deep trough; epistomegnathotectum:
   (= epistome, tectum) an often membranous dorsal projection of the anterior margin of the basis capitulum in Mesostigmata; often diagnostic at family-, genus- or species-levels; also often difficult to see without high magnification and good optics.
   convex, smooth; movable chelachela:
   a pincer, as in a pseudoscorpion's distal pedipalpal segments.
   of female unidentate.............................. Proctogastrolaelaps
   - Ventralventral:
   relating to the lower or under side; opposed to dorsal.
   area not sclerotized, only small anal shield with 3 circumanal setaecircumanal setae:
   in Mesostigmata, the three setae (postanal and pair of peranal) setae surrounding the anal opening.
   present.............................. 3

3. Fixed chelachela:
   a pincer, as in a pseudoscorpion's distal pedipalpal segments.
   of female and nymphs with pointed or rounded flange-like projection distally; leg IV with 1 or 2 erect macrosetae on telotarsustelotarsus:
   (= acrotarsus, apicotarsus) a distal division of the tarsus.  
   (pd2, +/- ad2); 3rd pair of sternal poressternal pores:
   (designations = stp or iv) in Mesostigmata, the lyrifissures in the intercoxal region; stp1-2 often occur on the sternal shield and stp3 is associated with the metasternal setae on a combined sternal-metasternal shield, on a separate sternal platelet, or in soft cuticle.
   absent.............................. Mucroseius
   - Fixed chelachela:
   a pincer, as in a pseudoscorpion's distal pedipalpal segments.
   without distaldistal:
   towards the free end of an appendage.
   flange-like projection; leg IV usually without macrosetae; 3rd pair of sternal poressternal pores:
   (designations = stp or iv) in Mesostigmata, the lyrifissures in the intercoxal region; stp1-2 often occur on the sternal shield and stp3 is associated with the metasternal setae on a combined sternal-metasternal shield, on a separate sternal platelet, or in soft cuticle.
   usually present.............................. 4

4. Dorsaldorsal:
   relating to the upper or back side; opposed to ventral.
   shield of adults with pair of deep midlateral incisions, lacking setae z3 on podonotalpodonotal:
   relating to the dorsal podosoma, the region of the idiosoma over the legs.
   region; movable chelachela:
   a pincer, as in a pseudoscorpion's distal pedipalpal segments.
   with 0 or 1 tooth; female without metasternal plates.............................. 6
   - Dorsaldorsal:
   relating to the upper or back side; opposed to ventral.
   shield of adults entireentire:
   a shield or sclerite with a continuous margin without incisions.
   , usually with setae z3 on podonotalpodonotal:
   relating to the dorsal podosoma, the region of the idiosoma over the legs.
   region; movable chelachela:
   a pincer, as in a pseudoscorpion's distal pedipalpal segments.
   with 3 teeth; with or without metasternal plates.............................. 5

5. Adults with 7–13 pairs of marginal (r–R) setae on soft lateral cuticle (rarely fewer if some r–R setae lacking); female with 14–15 pairs of setae on opisthonotalopisthonotal:
   dorsal opisthosoma.
   region of dorsaldorsal:
   relating to the upper or back side; opposed to ventral.
   shield and lacking metasternal plates (except in Orolaelaps).............................. Melichares
   - Adults with 1–4 pairs of posteriorposterior:
   the back part of the body or towards that region in comparison, e.g., 'posterior to'.
   marginal (R) setae on soft ventro-lateral cuticle, all others on edge of dorsaldorsal:
   relating to the upper or back side; opposed to ventral.
   shield; female with 18–22 pairs of setae on opisthonotalopisthonotal:
   dorsal opisthosoma.
   region of dorsaldorsal:
   relating to the upper or back side; opposed to ventral.
   shield; female usually with metasternal plates.............................. Proctolaelaps

6. Movable chelachela:
   a pincer, as in a pseudoscorpion's distal pedipalpal segments.
   unidentate; female with 1st pair of sternal setaesternal setae:
   in Mesostigmata, the five pairs of setae in the intercoxal region designated st1-5; st1-3 are present in the larva and usually are borne on a sternal shield in the adult female; st4, the metasternal setae, are added in the deutonymph, often are borne on metasternal platelets, and sometimes on the sternal shield; st5, the genital setae, are added in the protonymph and usually borne on or are inserted laterad the epigynal shield in the adult female.
   on soft cuticle in front of sternal shieldsternal shield:
   a shield in the anterior intercoxal region of parasitiform mites that bears one or more pairs of sternal setae.
   ; male with separate ventralventral:
   relating to the lower or under side; opposed to dorsal.
   & anal shields; male leg II with tarsal seta pv1 unmodified.............................. Xanthippe
   - Movable chela edentateedentate:
   with out teeth; usually referring to chelicerae.
   ; female with first pair of sternal setaesternal setae:
   in Mesostigmata, the five pairs of setae in the intercoxal region designated st1-5; st1-3 are present in the larva and usually are borne on a sternal shield in the adult female; st4, the metasternal setae, are added in the deutonymph, often are borne on metasternal platelets, and sometimes on the sternal shield; st5, the genital setae, are added in the protonymph and usually borne on or are inserted laterad the epigynal shield in the adult female.
   on sternal shieldsternal shield:
   a shield in the anterior intercoxal region of parasitiform mites that bears one or more pairs of sternal setae.
   ; male usually with consolidated ventrianal shieldventrianal shield:
   in Mesostigmata, a ventral shield bearing the anal opening, circum anal setae, and one or more pairs of ventral setae or pores (lyrifissures) [see anal shield]; maybe rather narrow or very broad and covering most of the gaster.
   ; male leg II with apicalapical:
   at the tip of a structure
   tarsal seta pv–1 slightly to conspicuously thickened.............................. 7

7. Tibiaetibia:
   (pl. tibiae) the leg segment between the genu and the tarsus.
   III and IV with 9 and 10 setae respectively (pl2 present); dorsaldorsal:
   relating to the upper or back side; opposed to ventral.
   shield with setae s6; female with hyaline anterior margin of epigynialepigynal:
   (also epigynial) of or relating to the female genital opening or a shield protecting it.
   shield rounded, and with genital setae on lateral edges of this shield; male tarsustarsus:
   (pl. tarsi) the subdistal leg segment between the tibia and the pretarsus (apotele).
   II with seta pv–1 knob- or spine-likespine-like:
   a seta or other structure that resembles a thorn or spine; spiniform.
   , and tarsustarsus:
   (pl. tarsi) the subdistal leg segment between the tibia and the pretarsus (apotele).
   III with 1–3 setae (always av2) knob-like; male spermatodactylspermatodactyl:
   (also spermadactyl) the 'sperm finger' on the chelicerae of male dermanyssine Mesostigmata used to transfer sperm to the secondary sperm system in the female; spermatodactyls take various forms, from simple finger-like processes to very long, contorted structures.  
   directed anteriorly.............................. Tropicoseius
   - Tibiaetibia:
   (pl. tibiae) the leg segment between the genu and the tarsus.
   III and IV with 8 and 9 setae respectively (pl2 absent); dorsaldorsal:
   relating to the upper or back side; opposed to ventral.
   shield lacking setae s6; female with hyaline anterior margin of epigynialepigynal:
   (also epigynial) of or relating to the female genital opening or a shield protecting it.
   shield usually truncated or emarginated, and with genital setae on soft cuticle flanking this shield; male tarsustarsus:
   (pl. tarsi) the subdistal leg segment between the tibia and the pretarsus (apotele).
   II with seta pv1 but slightly thickened, and tarsustarsus:
   (pl. tarsi) the subdistal leg segment between the tibia and the pretarsus (apotele).
   III without modified setae; male spermatodactylspermatodactyl:
   (also spermadactyl) the 'sperm finger' on the chelicerae of male dermanyssine Mesostigmata used to transfer sperm to the secondary sperm system in the female; spermatodactyls take various forms, from simple finger-like processes to very long, contorted structures.  
   directed posteroventrally.............................. Rhinoseius

Ecology and distribution

About 100 species of Proctolaelaps have been described from numerous habitats and associations. Some species are flower mites phoretic on hummingbirds, butterflies or honey opossums. Others are common inhabitants in beetle galleries, ant colonies, bumblebee nests, stored products, insect cultures, rotting fruit, and soil. Adults are found on a variety of insects and at least one species is a parasite of cockroaches.

References

• Colwell 1995Colwell 1995:
  Colwell RK. 1995. Effects of nectar consumption by the hummingbird flower mite Proctolaelaps kirmsei on nectar availability in Hamelia patens. Biotropica 27: 206–217.
• Egan and Hunter 1975Egan and Hunter 1975:
  Egan ME and Hunter PE. 1975. Redescription of a cockroach mite, Proctolaelaps nauphoetae, with notes on its biology. Annals of the Entomological Society of America 68: 361-4.
• Egan and Moss 1969Egan and Moss 1969:
  Egan ME and Moss WW. 1969. The life cycle and behavior of a cockroach mite, Proctolaelaps nauphoetae (Acari: Mesostigmata: Ascidae). Notulae Naturae 420: 1-9.
• Evans and Till 1979Evans and Till 1979:
  Evans EO and Till WM. 1979. Mesostigmatic mites of Britain and Ireland (Chelicerata: Acari-Parasitiformes): An introduction to their external morphology and classification. Transactions of the Zoological Society of London 35 (2): 145-270.
• Halliday et al. 1998Halliday et al. 1998:
  Halliday RB, Walter DE, and Lindquist EE. 1998. Revision of the Australian Ascidae (Acarina: Mesostigmata). Invertebrate Taxonomy 12: 1-54.
• Karg 1993Karg 1993:
  Karg W. 1993. Acari (Acarina), Milben Parasitiformes (Anactinochaeta) Cohors Gamasina Leach, Raubmilben. Die Tierwelt Deutschlands 59: 1-523.
• Krantz 1986Krantz 1986:
  Krantz GW. 1986. A manual of acarology [2nd ed., emended 1986]. Oregon State University Book Stores, Corvallis.
• Krantz and Ainscough 1990Krantz and Ainscough 1990:
  Krantz GW and Ainscough B. 1990. Mesostigmata. pp. 583-665. In: Dindal DL, ed. Soil biology guide. John Wiley & Sons, Brisbane.
• Lindquist 1971Lindquist 1971:
  Lindquist EE.  1971. New species of Ascidae (Acarina : Mesostigmata) associated with forest insect pests. Can. Entomol. 103: 919-42
• Lindquist and Evans 1965Lindquist and Evans 1965:
  Lindquist EE and Evans GO. 1965. Taxonomic concepts in the Ascidae, with a modified setal nomenclature for the idiosoma of the Gamasina (Acarina: Mesostigmata). Memoirs of the Entomological Society of Canada 47: 1-64
• Lindquist and Hunter 1965Lindquist and Hunter 1965:
  Lindquist EE and Hunter PE. 1965. Some mites of the genus Proctolaelaps Berlese (Acarina: Blattisociidae) associated with forest insect pests. The Canadian Entomologist 97: 16-32.
• McGraw and Farrier 1969McGraw and Farrier 1969:
  McGraw JR and Farrier MH. 1969. Of the superfamily Parasitoidea (Acarina: Mesostigmata) associated with Dendroctonus and Ips (Coleoptera: Scolytidae). North Carolina Agricultural Experiment Station Technical Bulletin No. 192, 162 pp.