BUTTERFLIES OF MONTANA. 21 



allied to the other members of the family. The caterpillar feeds on a 

 great variety of plants. 



Distribution It is found among the eastern valleys of the Rocky 

 Mountains and descends into Mexico. In Arizona it is quite common. In 

 Montana it is on the wing by the last of April. It is very similar to the 

 turn us of the eastern and middle states, but is larger, and with two tails 

 to the wings. It is rather common in the western end of the state, but 

 nowhere abundant. Wiley does not report it from the eastern end, ex- 

 cept to refer a specimen on the wing to either daunus or rutulus. Brande- 

 gee has taken it at Helena. 



THE TURNUS SWALLOW-TAIL. 



Papilio turnus, Linnaeus. 



Butterfly Expanse of male, 3.00 to 4.00 inches, 75 to 100 mm.; female, 

 3.50 to 5.00 inches, 87 to 125 mm. Ihis species very closely resembles 

 rutulus, or, rather, rutulus very closely resembles turnus. It may be 

 distinguished by the fact that the marginal spots on the under side of the 

 fore wings are separate, while in rutulus they join together. The species 

 is dimorphic in the female sex in the southern portion of the territory it 

 occupies. At first the black form was regarded as a distinct species, 

 but it is now known that the black and yellow females are of the same 

 species. By experiments it is shown that eggs from yellow females 

 produce black females, and conversely eggs from black females produce 

 yellow females. The dark or black female does not occur in Canada or 

 in the country northward and westward. Holland has obtained speci- 

 mens of a small dwarfed yellow form near Sitka. 



Early Stages The egg is green or bluish green, with occasionally 

 some reddish spots. The caterpillar feeds on the wild cherry and other 

 plants. 



Distribution It abounds in the wooded regions in the eastern United 

 States, often in great numbers, extending from New England to the Gulf 

 of Mexico. Westward it is found to the Rocky Mountains, extending 

 northward to Alaska. In the state it has been taken by Carrington and 

 Logan in 1871, locality not given. 



Several specimens of turnus are among Wiley's specimens in his Miles 

 City collection. 



