64 



APPLIED ENTOMOLOGY 



The Collembola may be characterized as: 



Apterygota without styli on the underside of the abdomen: cerci either 

 absent or very small and consisting of only one segment. Usually much 

 smaller than Thysanura and most of them with a ventral "spring." 



Fig. 36.— Springtail (Papirius fuscus Lucas) showing forked "spring" projecting forward 

 toward the head beneath the body. Greatly enlarged. From Lubbock.) 



The most famihar members of this order are probably the Snow 

 Fleas, which are sometimes seen in enormous numbers on snow, where 

 their dark color and their hopping movements make them noticeable 

 (Fig. 37). Some of the group often become a nuisance by gathering 



Fig. 37. — Snow Flea (Achoriiies nivicola Fitch) greatly enlarged. Real length K2 in^'h 



{From Folsom.) 



in maple-sap buckets on trees being tapped. Some also, feed on the leaves 

 of plants making tiny holes, which though of themselves unimportant be- 

 ing small, still afford the spores of fungous diseases excellent opportunities 

 for entrance to the plant tissues. In cases where work of this nature by 

 Collembola is sufficient to warrant it, spraying the leaves as soon as the 

 injury appears, with arsenate of lead, standard formula, is effective. 



