Source : Webster's Revised Unabridged Dictionary (1913)

June \June\, n. [L. Junius: cf. F. Juin. So called either from
   Junius, the name of a Roman gens, or from Juno, the goddess.]
   The sixth month of the year, containing thirty days.

         And what is so rare as a day in June? Then, if ever,
         come perfect days.                       -- Lowell.

   {June beetle}, {June bug} (Zo["o]l.), any one of several
      species of large brown beetles of the genus {Lachnosterna}
      and related genera; -- so called because they begin to
      fly, in the northern United States, about the first of
      June. The larv[ae] of the June beetles live under ground,
      and feed upon the roots of grasses and other plants.
      Called also {May bug} or {May beetle}.

   {June grass} (Bot.), a New England name for Kentucky blue
      grass. See {Blue glass}, and Illustration in Appendix.

Dor \Dor\, n. [Cf. AS. dora drone, locust, D. tor beetle, L.
   taurus a kind of beetle. Cf. {Dormouse}.] (Zo["o]l.)
   A large European scaraboid beetle ({Geotrupes stercorarius}),
   which makes a droning noise while flying. The name is also
   applied to allied American species, as the {June bug}. Called
   also {dorr}, {dorbeetle}, or {dorrbeetle}, {dorbug},
   {dorrfly}, and {buzzard clock}.

Source : WordNet®

June bug
     n : any of various large usually brown North American
         leaf-eating beetles common in late spring; the larvae
         feed on roots of grasses etc. [syn: {June beetle}, {May
         bug}, {May beetle}]