2 1 4 Zoology of Colorado 



excrement, but when they are large and cannot escape notice they 

 may find protection by being able to emit a disagreeable odor. 

 The following key will enable the student to separate the Colorado 

 swallow-tails: 



Tail of hind wings very short, light markings very pale. . indra 

 Reakirt. 



Tail or tails of hind wings long 1 . 



1. Each hind wing with two tails, and the inner angle also pro- 



longed; large species with yellow background and stripes 



(except submarginal bands) not heavy . . daunus Boisduval. 



Each hind wing with one tail 2. 



2. Anterior wings greenish black without spots or bands, hind 



wings more decidedly green . . philenor Linnaeus. 

 Anterior wings with at least some conspicuous markings ... 3. 



3. Middle of hind wings crossed by a suffused pale bluish band, 



but without yellow or white band or area . . troilus Lin- 

 naeus. 

 Hind wing with at least some conspicuous light bands or areas. 4. 



4. Ground color of wings creamy white eurymedon Lucas. 



Ground color of wings yellow 5. 



5. Neither anterior nor posterior wings with an extensive black 



basal area, but extreme base of anterior wings and a band 

 along inner margin of hind wings black; large species .... 

 rutulus Lucas. 

 Base of anterior wings (at least) broadly black 6. 



6. Much more than half of hind wings, before the broad black 



band, yellow 7. 



About half of hind wings, before the dark band, yellow; yellow 



band on anterior wings conspicuously broadening below 



bairdi hollandi Edwards. 



Much less than half of the hind wings, before the dark band, 



yellow 8. 



7. Dark band of hind wings with large blue spots; marginal yellow 



spots larger; larger species . . bairdi brucei Edwards. 

 Dark band of hind wings with small blue spots; smaller species 

 . . . zelicaon Lucas. 



8. Larger; inner edge of yellow band on hind wings strongly curved 



.... bairdi Edwards. 



