METAMORPHOSES. 5 



thorax is composed. The head has two antennas. The majority 

 are provided with two pairs of Avings, bnt some have only one pair, 

 and many have none. 



The nervous system consists of two parallel cords down the 

 middle of the lower surface of the body, united at intervals by nerve 

 centres called ganglia. From these nerves are sent off to the various 



Fig. l. 



HYMENOPTERA. 



DIPTSHA 



LEPIDOPTBR4 



TRICHOPTERA 



RHYNCHOTA 



ORTHOPTER. 



4PTEIA 



parts of the body. In insects of a most primitive type there is a 

 ganglion in each segment of the body, but in the higher insects these 

 ganglia are drawn more or less forward, often uniting, especially in 

 the thorax. 



Examples of the caterpillar of a Goat-moth (1000), a Hornet 

 (1002), Horse-fly (1004) and Summer Chafer (1006) are exhibited in 

 Table-case 29. 



