Genus Howardula
Cobb, 1921
Acarinocola Warren, 1941 (= genus dubiuma)
Tylenchinema Goodey, 1930
Photo Gallery- University of Missouri 

Characters of Aphelenchus Bastian, 1865, but without oesophageal bulb and with a non-bulbous onchium and much reflexed ovary.  "Female" finally a flaccid, cylindriod sack, without distinct alimentary canal, and otherwise much deteriorated.  Syngonic; male unknown.  Howardula may be related to Bradynema zur Strassen, 1892, but the latter has no onchium and even lacks a mouth opening.
(Description- Cobb, 1921)

Definition:  Allantonematinae.  Cuticle annulated; lateral fields present.  Head slightly offset by being narrower than body.  Tails conoid to pointed tips.  Female with well-developed, knobless spear; dorsal and subventral glands open close together not far behind the spear base.  Nerve ring and excretory pore further back.  Vulva posterior; single anterior gonad with ovary in undeveloped state and large uterus often full of sperm.  No post-vulval sac.  Rectum and anus distinct.  Male without spear and details of gland openings not determinable.  Spicules and gubernaculum present.  Bursa usually present.  Testis single, outstretched, producing many sperms.  The parasitic female is a mere reproductive sac, considerably enlarged, in which, of the gut, only the spear and anus remain visible.

Type speciesHowardula benigna Cobb, 1921
(Description-Goodey, 1963)

    Allantonematinae.  Single generation cycle; male lacking a stylet. Entomoparasitic female: In body cavity or ovary of insect host.  Inert or with slight mobility, obese, worm-like, white, not turning yellow or brown.  Vulva almost terminal.  Oviduct and ovary coiled.  Uterus enormous, packed with juveniles in ovoviviparous species and with eggs in oviparous species.  Stylet obscure in type species, but seen in others, rod-like without knobs, often sunken in body.  Oesophagus degenerate.  Produces enormous numbers of eggs or juveniles (up to 20,000).  Juveniles moult twice or thrice in the host, reach ovary and oviduct to escape through ovipositer or reach gut and escape through anus.  Partially free-living forms:  About 0.5 -0.6 mm long.  Cuticle finely striated; lateral fields narrow, with incisures.  Cephalic region continuous; sclerotization slight or absent.  Excretory pore anterior to nerve ring in type species, but may be posterior to it.  Female stylet stout, 12 -24 um long, often without basal knobs or thickenings; orifice of dorsal oesophageal gland half to more than one stylet length behind stylet base.  Vulva near anus.  Ovary rudimentary; uterus acts as a reservoir for sperm.  Tail elongate-conoid.  Male without a stylet or rarely with one which is degenerate.  Oesophagus degenerate.  Spicules about one anal body width long.  Gubernaculum weakly developed or absent.  Bursa poorly developed, reaching terminus, or absent.  The male dies after inseminating the preadult female.  The latter penetrates the host's larva or pupa, remains within and develops through metamorphosis to become adult in the haemocoel of the adult insect.
(Description- Siddiqi, 2000)

    Coleoptera: Apion, Carpophilus, Colaspis, Diabortica, Monolepta, Phyllotreta.
    Diptera: Copromysa, Oscinella, Sepsis, Drosophila.
    Siphonaptera: Ctenophthalmus.
    Acarina: Cosmolaelaps, Euryparasitus, Haemogamasus, Parasitus, Poecilochirus.

Type species
    Howardula benigna Cobb, 1921

Species found:       at:
H. benigna University of Missouri Sample