The Collaborative International Dictionary of English v.0.48:

Croton bug \Cro"ton bug`\ (b[u^]g`). [From the Croton water of
   New York.] (Zool.)
   A small, active, winged species of cockroach (Ectobia
   Germanica), the water bug. It is common aboard ships, and in
   houses in cities, esp. in those with hot-water pipes; --
   called also the German cockroach.
   [1913 Webster +PJC]

The Collaborative International Dictionary of English v.0.48:

Cockroach \Cock"roach\, n. [Sp. cucaracha.] (Zool.)
   An orthopterous insect of the genus Blatta, and allied
   genera.
   [1913 Webster]

   Note: The species are numerous, especially in hot countries.
         Those most commonly infesting houses in Europe and
         North America are Blatta orientalis, a large species
         often called black beetle, and the Croton bug
         (Blatta Germanica, formerly Ectobia Germanica),
         also called the German cockroach.
         [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

Croton bug
    n 1: small light-brown cockroach brought to United States from
         Europe; a common household pest [syn: German cockroach,
         Croton bug, crotonbug, water bug, Blattella
         germanica]