The Simplest Insects 



6i 



poiieii slaphylinus (from California), 

 the simplest living insect. (Natural 

 size indicated by line.) 



is a striking proof that Nature does not inevitably crush out all of her 

 first trials in favor of her later results! 



The Campodeidic contain another 

 genus, Nicoletia (Fig. 91), one species of 

 which, N . texensis, has been found in Cali- 

 fornia and Texas, and which may be dis- 

 tinguished from Campodea by its posses- 

 sion of three caudal appendages instead 

 of two as in the latter form. 



The Japygida? include but a single 

 genus, Japyx, represented in this country 

 by two described species and several as yet 

 undescribed forms found at Stanford Uni- 

 versity. Japyx subterrancus is a species 

 first found under stones at the mouth of 

 a small grotto near the Mammoth Cave 



(Kentucky). Japyx (Fig. 92) is larger F>g- qo.— Young and adult of Cam- 

 than Campodea, being about one-half inch 

 long, and is readily recognized by its caudal 

 forceps. lake Campodea its body is white and soft. 



The Lepismida:' include the familiar household fish- 

 moths and a number of similar forms which live under 

 stones and logs in soft soil at the bases of tree-trunks, 

 under dead leaves in woods, and sometimes on the damp 

 sand of seashores. Three genera of this family occur 

 in North America, which may be distinguished as 

 follows: 



Caudal appendages short; prothora.x very wide and body 



behind it tapering rapidly Lepismin.a. 



Caudal appendages long; body elongate and tapering 

 gradually backward. 



Eyes large and close together Machilis. 



Eyes small and far apart Lepisma. 



Lepisma is be.st known by the species L. saccharina 



(Fig. 86), which is the silverfish or fish-moth of the 



house. It is silvery white, with a yellowish tinge on 



the antenna' and legs, and is from one-third to two- 



,,. , . fifths of an inch long. The three long caudal appen- 



FiG. gi. — Xicoletia tex- . . ^ , 



ensis, from Califor- dages, characteristic of the genus, are conspicuous. It 



nia. (Eight times nat- fgg(^is chieflv on sweet or starchy materials, sometimes 



doing much damage in libraries, where it attacks the 



bindings. It attacks starched clothing, eats the paste off the wall-paper. 



