CLASSIFICATION AND DESCRIPTION OF COMMON INSECTS 



95 



BB. Body not covered with scales. 



C. Caudal appendages many-jointed. — Campodcidce. 

 CC. Caudal appendages sickle-shaped. — Japygidce. 

 AA. Abdomen with not more than six segments; antennae with not more than 

 eight joints; no caudal appendages. — Collembola Order. 

 B. Ventral spring present. 



C. Spring on penultimate abdominal segment. 

 D. Abdomen globular. — Sminthuridce. 

 DD Abdomen cylindrical. — Enlomobryidce. 

 CC. Spring on antepenult abdominal segment. — Podurida. 

 BB. Ventral spring absent. — Aphorurida. 

 Of the above Apterous families only one, the LepismidcB of the Thysanura, 

 contains forms that are of economic importance. 



ORDER THYSANURA 

 LEPISMIDiE (Fish-moths) 



The Fish-moth, Silver Fish, or "SUcker" 



Linn.) sometimes does injury to books, 

 papers, labels and starched clothing. It 

 shuns light and is quite active. 



Adult. — A minute, glistening, scaly, fish- 

 like active insect, wingless, 3^^ inch long, 

 body tapering to hind end where are three 

 long, bristle-shaped appendages; antennae 

 prominent; coxae strongly developed; biting 

 mouth parts. 



Another species, Lepismadomestica Pack., 

 is found in bakeries and mills in some locali- 

 ties. It has dusty markings on its upper 

 surface and is 3-^ inch long. 



Control. — Frequent use of fresh insect 

 powder, sodium fluoride, or a poison-bait 

 of sweetened gluey paste and white arsenic 

 on bits of cardboard. 



{Lepisma saccharina 



PODURID^ (Springtails) 



IT 



Fig. 50.— The silver fish 

 {Lepisma saccharina) . {After 

 Marlatt.) 



Two species may be noted in passing: 

 Achorutes armatum sometimes attacking seedlings causing disfigure- 

 ment and loss, and A. nivicola often abundant in maple sap in early 

 spring. Both species are minute, and have some of the habits of 

 flea-beetles (Fig, 51). 



