138 



NATURAL HISTORY OF ARTHROPODS. 



silken trimmings of furniture ; and at times will injure books by devouring the paste 

 of the binding, as well as by eating holes in the leaves and the binding. I have 



seen old envelopes which had been riddled 

 with holes gnawed by these insects. 



Another species locally very common is 

 Lepisma domestica, which I discovered liv- 

 ing in great abundance in a house, especi- 

 ally the kitchen, about the range. This is 

 a heat-loving species, and it may prove iden- 

 tical with Xepisma thermophila of houses 

 in Brest, France. Our most common out- 

 of-door species is Lepisma quadriseriata, 

 which may be seen running over the walls 

 of outhouses. 



The genus Machilis stands at the head 

 of the Thysanura; its advanced standing 

 is seen in the rather large, full compound 

 eyes, and its well-developed mouth-parts. 

 The body ends in three bristles, but the 

 chief characteristics are the two-jointed 

 stylets, arranged in nine pairs along each 

 side of the abdomen, and which remind us 

 of the abdominal legs of myriapods. They 

 affect damp, though not wet places, living 

 in partial darkness under stones. Our com- 

 mon eastern species is Machilis variabilis, but other species occur in the western 

 states. 



A. S. Packard, Jb. 



Fig. W2. — lapyx solifugus, enlarged. 



Fig. 203. — Lepisma socc/iarina, enlarged. 



