PERIPATUS, MYRIAPODS, AND INSECTS. 



181 



the ordinary observer, this being probably primarily due to the 

 small size of the individual Insect, which leads the unreflecting to 

 treat the creature as of little importance. . . . The largest 

 Insects scarcely exceed in bulk a mouse or a wren, while the 

 smallest are almost or quite imperceptible to the naked eye, and 



Fig. II. 



Lithobius dissected 

 (after Vogt and Yung). 



a, Antennse ; 



b, Poison -claws ; 



c, Brain ; 



d, Salivary glands ; 



e, Legs ; 



/, Nerve cord ; 



g, Malpighian tube ; 



h, Malpighian tube ; 



i, Vesicula seminalis ; 



/, Accessory gland ; 



k. Accessory gland ; 



/, Testis ; 



;«, Thigh-gland ; 



«, Digestive tube. 



yet the larger part of the animal matter existing on the lands of 

 the globe is in all probability locked up in the form of Insects. 

 Taken as a whole, they are the most successful of all the forms of 

 terrestrial animals. 



