THE STUD Y OF INSECTS. 



clothed. The palpi are short, usually but little developed ; 

 and the maxillae are present. The most important features in 

 the venation of the wings (Figs. 386, 387) is the union of 

 veins V a and V, of the fore wings with cubitus, making 

 it apparently four-branched ; and the growing together of 

 subcosta and radius of the hind wings for a considerable 

 distance. The extent of the union of these two veins varies 

 greatly in the different genera; but so far as we have ob- 

 served it is always less 

 Tr rj:r 4 than four fifths of the 

 length of the discal 

 cell. This character is 

 of use in separating 

 these insects from the 

 Zygaenidae in which 

 the union of these two 

 veins is carried farther. 

 The larvae of the 

 Tiger-moths are clothed 

 with dense clusters of 

 hairs. In fact a large 

 proportion of our com- 

 mon hairy caterpillars 

 are members of this 



FIG. 387. Wings of Pygoctenucha funerea. 



family. In some species, certain of the clusters of hairs 

 are much larger than the others, resembling in this 

 respect the clothing of the Tussock-moths. Most larvae 

 of the Arctiids feed upon herbaceous plants, and many 

 species seem to have but little choice of food-plant ; 

 but certain common species feed upon leaves of forest- 

 trees. 



About one hundred and fifty North American species 

 have been described. The following are some of the more 

 common representatives. 



Among the more beautiful of the Tiger-moths is a genus 

 the species of which are snow-white or light yellow with the 



