Key to species of the genus Centrorhynchus of the birds of Ukraine and adjacent territories

1а. Pear-shaped proboscis with extension in the middle part. ........................................................................... 2

1b. Proboscis other form...........................................................................................................................................3

2a. In anterior and posterior parts of proboscis same 30–36 longitudinal hook rows. To a level of attachment of the proboscis receptacle 12–13 hooks in row. ................................................................. C. spinosus

2b. In anterior part of proboscis 34 longitudinal hook rows, in posterior part — 40. To a level of attachment of proboscis receptacle 9–10 hooks. ................................................................................................. C. narcisae

3a. Anterior part of proboscis almost cylindrical without evident narrowing in level of attachment of proboscis receptacle..................................................................................................................................................4

3b. Anterior part of proboscis spherical or spade-shaped with evident narrowing in the level of attachment of proboscis receptacle........................................................................................................................................6

4а. Proboscis with 38–42 longitudinal hook rows of 26–27 hooks. ................................................... C. magnus

4b. Proboscis with 26–34 longitudinal hook rows of 19–21 hooks....................................................................5

5а. Proboscis with 26–30 longitudinal hook rows. Blade of the largest hook 42 length. ........... C. amphibius

5b. Proboscis with 30–34 longitudinal hook rows. Blade of the largest hook 50–65 length. ............................ ..................................................................................................................................................... C. globocaudatus

6а. Each longitudinal row with 19–20 hooks. Eggs 45–55 × 25. ......................................... C. polissiensis sp. n.

6b. Each longitudinal row with 13–18 hooks. Eggs 56–72 × 28–35...................................................................7

7а. First 7–10 hooks in each longitudinal row large with strong roots. ........................................... C. buteonis

7b. First 3–6 hooks in each longitudinal row large with strong roots. .............................................................. 8

8а. First 3–5 (usually 4) hooks in each longitudinal row large with strong roots. Eggs 56–65 × 28–30. ........ ................................................................................................................................................................ C. aluconis

8b. First 4–6 (usually 5) hooks in each longitudinal row large with strong roots. Eggs 68–72 × 33–35. ........ ............................................................................................................................................................ C. conspectus