Two new phoretomorphic Siteroptes from galleries of the southern pine beetle (Acarina; Pyemotidae).

Intro~Iuction , This paper provides taxonomic descriptions of two pyertlotid mite species displaying polyrriorphic features discovered by MOSER & CROSS (1975). i'olyrrzorphisrn in the Acarina was first noted by CANESTRIYI in 1888 for I Z I ~ i ~ ~ g l j j p I ~ u s ecI~1r~opzls (FUJIOVZE r' .: KOBIN). He associated the heterorrlorphic male with the norrnal horrzocortlorphic rnale of this species. Later, MICHAEL (1 901) substantiated CANESTRINI'S discovery antl introtluced the term hypopus for another stage or forrrl (deutonyrnph) of the sarile species. This discovery had great biological significance. T t showed that rnites rnade adaptations to environriiental conditions by physiological chaligcs and that this form or stagc was not a separate taxon. Reports of observations and studies on polymorphism in the Aearina are few. O U D E ~ ~ A N S (1906) antl ~ Z A I C E R (1949) reportctl tliat htbterornorphic rnnles occurred in the farnily Cheyletidae. Recently, SMILEY [in press] and SJIILEY a' ~ I O S E R (1975) have studied a predatory rriale cheyletid rnite which is now known to exemplify such a condition. Previously, this characteristic has been reporter1 only for the malt:. Rec.ently, i t was discovered in the farnily by RACK have observetl hetcrorilorphic Inales in the genus S t l ~ r ~ ~ o p i t ~ ~ l j o i d c B. RAARLOV (1974 Personal Cornrr~ul~ication) has found a heterorrlorphic lrialc for Orrc?tltociieylet;~i I~nZlcne SBIILEY. XOSER & CROSS (1975) defilied the terrrl "JS1~oretoriior~)h" as a ht~tc~rorr~orpl~ic ftkrnrtle spcbcializt~tl for phoresy. Because of this discovc~r~. a n e w generic classification for t2lr farliily I'yernc~tidae is nectsssat.y. Lillso, the gentbric narliev applicbtl for species tlcscribc.rl here rrla>-prove to be provisional. I'olyrrlorphisrn will rtntlo-nbtabl?; he founct sorrlr (lay arrlong other fa~ililies of the Tarsont~rr~oidc~a ancl is strongly suspectt~tl to occur in the farnily Tarsoncrnitlae for tht: genus Pse~iiiitctr~ci?~eini)ides V I T Z T H ~ T ~ I. Jlrtles are not iinown for this genus except for bhe species tleseribotl by WIXG (1939). l t l o s ~ n 8 CROSS (1976) pr.esisnt phototuicrograplzs for the species bt~ing described here. I n their paper figures 1 ant1 2 are terrr~etl "S'lter.r~~trv forrri" for the norrrlal fernalt: ant1 "YrrX;t?rlirstc?* f o r ~ ~ z " for the phorttor~iorph. Also, figrises 3 axit1 3, arc termed '"iteroptes forrtl" …