SUBORDER COLLEMBOLA 



This suborder is composed of very minute insects which 



possess the faculty of springing suddenly, and which when 



alarmed make use of this means of escaping. They are found in 



the spring in the Northern States on bright sunny days when the 



snow is thawing, frequently in great numbers on the surface of 



the snow. They are also found on the surface of water, in old 



wells, and even at considerable distances under the surface of the 



ground feeding apparently upon vegetable mold. 



Five families are represented in the United States, which 



may be distinguished by the following table: 



A ventral spring below the abdomen i 



No ventral spring below the abdomen .... Family Aphoruridct 



, —Ventral spring on the second from last abdominal segment 



Family Poduridce 



Ventral spring on the next to the last abdominal segment. . 2 



2_Abdomen elongate, cylindrical, much longer than broad 



Family Entomobrytdce 



Abdomen globular, but little longer than broad 3 



5~Last segment of the antennse long, ringed • • • 



■^ . . Family Smynthuridce 



Last antennal segment short, with a whorl of hairs 



Family Papiritdx 



385 



