HOW TO KNOW THE IMMATURE INSECTS 



37a. Prespiracular wart on prothorax with 3 setae. 



Fig. 466 Family YPONOMEUTIDAE 





'PROTHol\A\ 



Fig. 466. Setal 

 map of prothor- 

 ox. 



37b. Prespiracular wart on prothorax with 2 setae 



38a. Tubercle vii on meso- and metathorax with 2 setae. 



.38 

 ,39 



38b. Tubercle vii on meso- and metathorax with 1 seta. 



Fig. 467 FamUy NOCTUIDAE 



About 20,000 species have been 

 described. The caterpillars are 

 commonly known as armyworms, 

 cutworms, etc. Night is their 

 usual feeding time, but when 

 very numerous they often spread 

 out during the day as well. Some 

 feed on seeds and some are stem 

 borers while the great majority 

 are foliage feeders. They are no- 

 torious pests of agricultural crops. 

 The corn earworm, Heliothis armi- 

 geia (Hubner) is a cosmopolitan 

 pest. 



Fig. 467. o, Setal map of mesothorax; 

 b, Tomato fruitworm, or corn earworm, 

 Heliothis ormigera (Hbn.); c, varie- 

 gated cutworm, Peridromo margaritosa 

 (Howorth). (U.S.D.A.) 



Fig. 468. Thyatira derasa. 



39a. Setae minute; tubercle reduced to obscure rings; head usually 



wide; prolegs reduced. Fig. 468 Family THYATIRIDAE 



The larvae of this small family are 

 spanworms traveling like the geome- 

 trids. There are known as the beautiful 

 mining moths, the "beauty" belonging 

 to the adults. The naked caterpillars 

 sometimes live gregariously in webs. 

 They pupate in a cocoon. 

 39b. Setae heavy, almost always spinulose; with conspicuous tub- 

 ercles 40 



40a. Tubercle iii of abdomen with 2 setae. 



Fig. 469 Subfamily Lithosiinae, ARCTIIDAE 



The caterpillars possess tufted 



hairs whicTi are much reduced in the 



last instar. This subfamily includes 



about 50 North American species. 



Fig. 469. Oenistis quodro. The caterpillars feed upon lichens. 



165 



