HETEROCHROSIS IN ESSEX BIRDS AND THEIR EGGS. 185 Skylark. Alauda a. arvensis L. Unrecorded. Complete .. 1 Complete partial 4 1 (male, cinnamon) Partial .. . . 2 Total .. 7 Ref.: The Birds of Essex (Christy); The Field, vol. 36, p. 236, vol. 116, p. 955 ; A History of the Birds of Essex. Meadow-Pipit. Anthus pratensis (L). Complete .. 0 Complete partial 1 Partial .. .. 1 Total .. 2 Ref.: The Birds of Essex (Christy); The Field, vol. 74, p. 545. Pied Wagtail. Motacilla alba yarrellii Gould. Complete .. 0 Complete partial 0 Partial .. .. 3 Total .. 3 Ref.: The Essex Nat., vol. 15, p. 259; The Felsted School Scientific Soc. Report, No. 25; A History of the Birds of Essex. Red-backed Shrike. Lanius c. collurio L. Complete .. 0 Complete partial 0 Partial .. .. 1 Total .. 1 Ref.: The Field, vol. 90, p. 389. Whitethroat. Sylvia c. communis Lath. Complete .. 0 Complete partial 0 Partial .. .. 1 Total .. 1 Ref.: The Birds of Essex (Christy).