224 APPENDIX. 



fine sand. In the centre of the dish was set a circular box of card, 

 without bottom, 2 inches in diameter, and 14 inches high. In this box 

 bread moistened with beer, a bait very attractive to Cockroaches, 

 was placed, and renewed daily. The four Cockroaches were allowed 

 to run about in the dish outside the box, and to feed upon the 

 bread at pleasure by climbing over the enclosure. Observations 

 were made late at night for a month, when it was found that, 

 except on the first night, when the Insects ran all over the dish, 

 none of the Cockroaches without antennae made their way to the 

 food ; while twenty-three times one of the Cockroaches without palps, 

 but with antennae intact, was found to be feeding ; in one instance, 

 both were so found. 



Plateau observes that a special sense of smell can only be claimed 

 for organs which are able to detect faint and distant odours, and 

 that experiments made with powerful odours close to the body of 

 the Insect may lead to fallacious results. The perception of faint 

 odours cannot be effected by the palps or cerci of the Cockroach, 

 but only by the aiitennse. 



THE END. 



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