The Collaborative International Dictionary of English v.0.48:

Hypoderma \Hyp`o*der"ma\, n. [NL. See Hypo, and derma.]
   1. (Bot.) A layer of tissue beneath the epidermis in plants,
      and performing the physiological function of strengthening
      the epidermal tissue. In phanerogamous plants it is
      developed as collenchyma.
      [1913 Webster]

   2. (Zool.) An inner cellular layer which lies beneath the
      chitinous cuticle of arthropods, annelids, and some other
      invertebrates.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Hypoderma
    n 1: in some classifications considered the type genus of the
         family Hypodermatidae: warble flies [syn: Hypoderma,
         genus Hypoderma]