322 THE STUDY OF INSECTS. 



are much lighter in texture, being extended over all of the 

 leaves fed upon by the colony. 



The Isabella Tiger-moth, Pyrrharctia Isabella (Pyr-rharc'- 

 ti-a is-a-bel'la). " Hurrying along like a caterpillar in the 

 fall" is a common saying among country people in New 

 England, and probably had its origin in observations made 

 upon the larva of the Isabella Tiger-moth. This is the 

 evenly clipped, furry caterpillar, reddish brown in the 

 middle and black at either end, which is seen so commonly 

 in the autumn and early spring (Fig. 394). Its evident haste 



to get somewhere, in the 

 autumn, is almost painful to 

 witness. A nervous anxiety 

 is apparent in every undulat- 



^. ^.-Pyrrharctia nabella, larva. j ng movement Q f its body . 



and frequently its shining black head is raised high in the 

 air, and moved from side to side, while it gets its bearings. 

 Occasionally after such an observation it evidently finds it 

 is mistaken, and turns sharply and hastens along faster than 

 ever in another direction. So far as we can judge, its ex- 

 citement comes from a sudden fear that winter will over- 

 take it before it can find a cosy, protected corner in which 

 to pass its winter sleep. In the spring it comes forth again, 

 and after feeding for a time makes a blackish-brown cocoon 

 composed largely of its hair. The adult is of a dull grayish 

 tawny-yellow, with a few black dots on the wings, and fre- 

 quently with the hinder pair tinged with orange-red. On 

 the middle of the back of the abdomen there is a row of 

 about six black dots, and on each side of the body a similar 

 row of dots. 



The Yellow-bear, Spilosoma virginica (Spil-o-so'ma vir- 

 gin'i-ca). The larva of this species is one of the most com- 

 mon hairy caterpillars found feeding on herbaceous plants. 

 It was named by Harris the Yellow-bear on account of the 

 long yellow hairs with which the body is clothed. These 

 hairs are uneven in length, some scattered ones being twice 



