fontanelle
From ZooTerms (Dictionary of Invertebrate Zoology)
fontanelle also fontanel (noun; French fontannella, little fountain): (Arthropoda: Insecta) In Isoptera, when present, a small circular or slit-shaped orifice of the frontal or cephalic gland near the center of the head, through which a liquid is emitted; a frontal pore.
