224 



AN INTRODUCTION TO ENTOMOLOGY 



AA. Body not clothed with scales. Median caudal filament wanting. Eyes 

 wanting. Jaws overgrown by folds of the genae. (The Entotrophi). 



B. Cerci many- jointed and filiform Campodeid^ 



BB. Cerci forceps-like Japygid^ 



Family Machilid^. — This family is represented by_ the genus 

 Mdchilis, of which several species occur in North America. These 

 insects are found in heaps of stones and in other 

 concealed places; they are very active and leap 

 with agility when disturbed. They are about 

 12 mm. in length 



Family Lepismatid^. — The best-known repre- 

 sentative of this family is the silverfish or fish-moth 

 Leptsma saccharma (Fig. 228). It is silvery white 

 with a yellowish tinge about the antennns and legs 

 and measures about 8 mm. in length. It is often 

 a troublesome pest in laundries, libraries, and mu- 

 seums, as it injures starched clothes, the bindings 

 of books, labels, and other things on which paste or 

 glue is used. The popular names were suggested by 

 the clothing of scales with 

 which the body is covered. 

 This pest can be destroyed 

 by the use of pyrethrum or 

 by a poisoned bait, consist- 

 ing of a thin boiled starch 

 paste to which has been add- Fig- 228.—Lepisma 

 ed from three to five per ^accMnna (After 



. . • xi. 4- Lubbock.) 



cent white arsenic ; the paste 



is spread on bits of cardboard, which are put 

 in the places frequented by the pest. 



Another common representative of this fam- 

 ily is the fire-brat, Thermohia domestica. This 

 species resembles the fish-moth in general ap- 

 pearance except that it has dusky markings on 

 its upper surface. It is remarkable for fre- 

 quenting warm and even hot places about 

 ovens, ranges, and fireplaces. It can be destroyed 

 in the same manner as the preceding species. 



Family Campodeid^. — The best-known 

 member of this family is Campodea staphyllnus 

 (Fig. 229). It lives in damp places under stones, 

 fallen trees, or in rotten wood and leaves. It is a 

 very delicate, small, white insect, about 6 mm. 

 in length. It has on the first abdominal seg- 

 ment a pair of appendages which occupy a 

 position corresponding to that of the thoracic 

 legs and each consists of two or three segments. 

 Family Japygid^. — This family is repre- 

 sented by the genus Jdpyx, of which two species 

 have been found in this country. These insects can be recognized by 

 the forceps-like form of the cerci (Fig. 222). They are small, deli- 

 cate, uncommon insects, found under stones. 



Fig. 229. — Campodea 

 staphylinus. (After 

 Lubbock.) 



