HOW TO KNOW THE IMMATURE INSECTS 



26a. Meso- and metathorax with seta ia in front of ib and well sep- 

 arated; abdominal seta iv above level of spiracle. 

 Fig. 447 Family HEPIALIDAE 



MeiorHOKAX AODO/^INAK JF«V£«7 



Fig. 447. a, Hepialus • 

 hiimuli; b, setal map 

 of mesothorax; c, 

 setal map of an ab- 

 dominal segment. 



The caterpillars are all plant borers in- 

 cluding roots, stems, twigs of grasses, shrubs 

 and trees. Some species are quite large and 

 often somewhat wrinkled. Rather numerous 

 hairs arise from tubercules. The larvae are 

 usually dusky, whitish or tinged with yellow. 

 The adults are narrow winged medium to 

 large sized moths and are known as swifts. 



26b. Meso- and metathorax with seta ia and ib closely associated; 

 abdominal seta iv below level of spiracle. 

 Fig. 448 Family YPONOMENTIDAE 



Fig. 448. a. Diamond- 

 back moth, Plutello 

 moculipennis (Curt.); 

 b, setal map of meso- 

 thorax; c, setal map 

 of an abdominal seg- 

 ment. 



The caterpillars are often found gregariously 

 living in webs or mining in leaves, twigs and 

 fruits. They are destructive to conifers and other 

 trees. The species here pictured feeds on mem- 

 bers of the mustard family. The small green 

 caterpillars start as miners but presently feed on 

 the surface of the plant. 



159 



