378 



THE STUDY OF INSECTS. 



with black lines on the veins. Between the two rows of 

 spots on the hind wings there are many blue scales ; these are 

 more abundant in the female. Near the anal angle of the 

 hind wing there is an orange spot with a black center. On 

 the lower surface of the wings the yellow markings become 

 mostly orange and are heavier. 



This species is found throughout the United States and 

 in the southern parts of Canada. 



The Tiger Swallow-tail, Jasoniades glaucns (Jas-o-ni'a-des 

 glau'cus). The larva of this butterfly (Fig. 458) is even more 



striking in appearance than that of the 

 preceding species. When full grown it is 

 dark green, and bears on each side of the 

 third thoracic segment a large greenish- 

 yellow spot, edged with black, and enclos- 

 ing a small purple spot bordered with 

 black. This caterpillar has the curious 

 habit of weaving upon a leaf a carpet of 

 silk, upon which it rests when not feed- 

 ing ; when nearly full grown, instead of 

 spinning a simple carpet as before, it 

 stretches a web across the hollow of a 

 leaf and thus makes a spring bed upon 

 which it sleeps (Fig. 458). 



In the adult state two distinct forms of 

 this insect occur. These differ so greatly 

 in appearance that they were long con- 

 sidered distinct species. They may be 

 distinguished as follows : 

 (i) The Turnus Yorm, Jasoniades glaiicus turnus. The 

 wings are bright straw-yellow above, and pale, faded straw- 

 yellow beneath, with a very broad black outer margin, in 

 which there is a row of yellow spots. On the fore wings 

 there are four black bars, extending back from the costa ; the 

 inner one of these crosses the hind wings also. This form 



FIG. 458. Jasoniades glau 

 cus, larva upon its bed. 



