epiphallus

epi- +‎ phallus

epiphallus (plural epiphalli)

1. (entomology)
   1. In some orthopterans, a plate adjacent to the genital complex.
      • 1981, Daniel Otte, The North American Grasshoppers: Acrididae: Oedipodinae‎, page 92:

        Hadrotettix and Heliastus lack pale streaks but possess trilobed epiphalli, which led me to look for other characteristics shared with the Hippiscus group.

   2. In some dictyopterans, a pair of valves adjacent to the phallus.
      • 2006, A.P. Rasnitsyn, History of Insects‎, page 274:

        Male genitalia strongly asymmetrical, partially concealed by sternum 9, comprised by basisclerite, paired epiphalli (left with titillator), and hypophallus; hook process (=L3 sclerite after MCKITTRICK 1964) missing (KLASS 1997).

2. (malacology) In some gastropods, an enlargement of the vas deferens that continues beyond the apex of the penis.
   • 2012, A. South, Terrestrial Slugs: Biology, ecology and control‎, page 110:

     In mature Arion the atrium is divided into upper and lower atria, with the oviduct, spermatheca duct and epiphallus opening into the upper atrium.