34 REPORT OF NEW JERSEY STATE MUSEUM. 



THERMOBIA Bergr. 



T. domestica Pack. The common "silver-fish" or "fish moth" found every- 

 where in houses, and usually in dry places around kitchen stoves, in 

 pantries, and even in dusty drawers. Feeds on starchy material, 

 and sometimes gnaws the bindings of books. All these species are 

 economically harmless. 



SCOLOPENDRELLA Gerv. 



S. gratiae Ryder. In damp places, under leaves and mold; resembles 

 a minute larval centipede. 



CAMPODEA Westw. 



C. americana Pack. Common everywhere in woods, under stones and 

 leaves. 



MACHILIS Latr. 

 M. variabilis Say. Generally distributed in the Atlantic States. 



Sub-order COLLEMBOLA. 



Much more abundant in species and specimens, and all small or very 

 small. They are distinguished by a pair of short anal spines or "furcula," 

 which are turned under the body and form a spring or leaping organ, 

 which gives them the common name "spring-tails." Most of the species 

 are feeders on vegetable decay, and they occur literally in thousands on 

 manure beds, in toad-stools, on stored fermenting vegetables, in cellars 

 and generally in damp places. A few species occur on living, healthy 

 plants, but not in such a way as to prove injurious. The insects are very 

 light, and after a heavy rain thousands may be seen hopping about on 

 the surface of the pools formed in low meadows. I have seen millions 

 on the water covering a cranberry bog reflowed late in May or early June. 



SMYNTHURUS Latr. 



S. arvalis Fitch. This and the four next following 

 species are found on garden plants and are locally 

 common. 



S. elegans Fitch. With the preceding. 



S. hortensis Fitch. Common on grasses. 



S. quadrimaculatus Ryder. Locally common. 



S. clavatus Banks. Under rotten bark, Sea Cliff, Long 

 Island. 



Fig. 2. Podurid 



with spring s - rnacgi I livrayi Banks. Long Island, on weeds, in May. 



extended. 



