io6 



FIRST LESSONS IN ZOOLOGY 



smell far more than on sif^ht or hearing for the dis- 

 covery of food, and for becoming aware of the pres- 

 ence of their enemies and the proximit)- of their mates 

 and companions. The organs of smell of insects are 

 situated principall)' on the antennae or feelers (fig. 72), 

 a single pair of which is borne 

 on the head of every insect. 

 That many insects liave an ama- 

 zingly keen sense of smell has 

 been shown by numerous experi- 

 ments, and is constantly proved 

 by well-known habits. If a small 

 bit of decaying flesh be inclosed 

 in a box so that it is wholly con- 

 cealed, it will nevertheless soon 

 be found by the flies and carrion 

 beetles that either feed on carrion 

 or must alwaj'S lay their eggs in 

 decaying matter so that their 

 carrion-eating larva; may be pro- 

 \'ided with food. In Jordan and 

 Kellogg's "Animal Life" is 

 given the following illustration 

 of the remarkable sense of smell 

 possessed by certain insects: " In 

 the insectary at Cornell Universit}', 

 a few }-ears ago, a few females of 

 the beautiful Promethea moth were 

 inclosed in a box, which was kept inside the insectary 

 building. No males had been seen about the insectar)' 

 nor in its immediate vicinit)', although they had been 

 sought for by collectors. A few hours after the beginning 

 fjf the captivity of the female moths there \\'ere forty male 

 I'rometheas fluttering about over the glass roof of the 

 insectar)'. They could not sec the females, and j^et had 



Fio. 72. — 'I'liL- unteiina of 

 a carrion lieclle, witli 

 tlie terminal three seg- 

 ments enlarged and flat- 

 tened, a n d bearing 

 many " smelling-pits." 

 the anteiina tlm^ ^er\ing 

 as an olfactory organ. 

 (Much enlarge<l; photo- 

 micrograph by Geo. O. 

 Mitchell.) 



