HOW TO KNOW THE IMMATURE INSECTS 



5b. Mouth parts adapted for 

 chewing. Fig. 54 6 



Fig. 54. Chewing mouth parts: a, carabid 

 larva; b, grasshopper. 



6a. Labium when extended, usually 4 or more times as long as broad, 

 scoop-like in structure and when folded serves as a mask that 

 covers the other mouth parts; plate-like gills may occur at caudal 

 end of abdomen; aquatic life. Fig. 55. Order ODONATA page 67 



The damselflies 

 and dragonflies are 

 the members of this 

 order which includes 

 about 5,000 describ- 

 ed species. The 

 naiads are exten- 

 sively aquatic, liv- 

 ing in various sit- 

 uations i n fresh 

 water. Many live 

 hidden in sand or 

 mud, etc. Without 

 exception all the 

 naiads are preda- 

 cious, feeding upon 

 various forms o f 

 aquatic life. The 

 principal external changes involved during metamorphosis include an 

 increase in the size of the compound eyes, and during the last few 

 instars, ocelli become evident; the antennal segments increase in num- 

 ber, and the wing-rudiments undergo certain changes with the result 

 that the developing hind wings overlap the anterior pair; the caudal 

 gills change in the Zygoptera. 



Fig. 55. a, Agrion sp.; b, labium of Libellula Igctuosa 

 Burmeister; c, Libellulo luctuosa Burmeister. 



6b. Labium of normal type, not modified into a scoop nor hinged. ... 7 



32 



