HOW TO KNOW THE IMMATURE INSECTS 



53b. Setae subequal or sometimes with setae and prominent warts 

 and spines 54 



54a. 8th abdominal segment with a dorsal horn, or plate, 



or tubercle 55 



54b. 8 th abdominal segment without a dorsal horn, or plate, 



or tubercle ^ 58 



55a. Body with numerous branching spines or enlarged tubercles. ... 56 

 55b. Body with at most 2 pairs of small spines on thorax 57 



56a. Head angulated or spined dorsally, or abdomen with several mid- 

 dorsal spines; crochets of prolegs usually triordinal. 

 Fig. 484 Family NYMPHALIDAE 



Fig. 484. 

 tiopa. 



a, Basilarchia ostyonox Fab:; b, Vanessa an- 



About 4,000 species have been described. The caterpillars are 

 usually spiny but some are naked. The chrysalises are suspended by 

 the cremaster and the head is held downwards. They are often mark- 

 ed with silver or gold ornamentations. The adults are butterfhes. 



56b. Head rounded; crochets biordinal. 



Fig 485 



Fig. 485. Q, 

 crochets. 



Samia cecropia L.; b, a proleg with 



....Family SATURNIIDAE 



The caterpillars chiefly 

 feed on broad-leaved de- 

 ciduous and evergreen 

 trees. They are called 

 giant or wild silkworms. 

 No less than 30 species in 

 oriental Asia are able to 

 produce usable silk. 

 57a. Segments with 6 or 8 annulets; prolegs not widely separated. 



Fig. 486 Family SPHINGIDAE 



About 900 species have been 

 described. The caterpillars are 

 called hornworms because of the 

 presence of a horn-like process on 

 the 8th abdominal segment. Some 

 larvae assume grotesque attitudes 

 which are thought to be respon- 

 sible for the name "sphinx moth'' 

 or "sphinx caterpillar". 



Fig. 486 Tobacco hornworm, 

 porce sexto (Johanssen). 



Pro to- 



170 



