92 



GEOLOGY OF LA SALLE COUNTY. 



workmanship. Kpeira vulg-aris is very common, less 

 so, another Epeira having a salmon colored bod}^', 

 curiously waved and streaked with brown. We have 

 also a small, jet black, hairy spider, w^th a small, 

 o-reen blotch in the center of its back, in the middle of 

 which is a red spot. We have also pale yellow, white 

 and other colored creatures of this class, some small, 

 some large, some long- and some short-legg-ed, which 

 we must pass over without further mention. 



The Phalang-eta or long- leg's, Daddylong-leg's, 

 Father Graybeards or Harvestmen, are common, and 

 at once recognized by the small, roundish body and 

 very long- legs. 



The Acarina or mites are small, generally parasitic 

 insects, the cause of the itch, sheep scab, &c. A few, 

 however, live in the ground. Among these, Trambid- 

 ion, of a bright red color, often seen in the spring in 

 the garden. The ticks, Ixodidae, are large mites. 

 They are common in the woods, and are often found on 

 animals and sometimes on man. The sheep tick be- 

 longs to the diptera. 



The myriapods or centepedes are not numerous; 

 the Chief or lithobius Amsricanus, having a flattened 

 body and about 30 leg's. It is found about cellars, un- 

 der chips and about refuse heaps. It devours insects 

 and is harmless. It is very quick in its movements. 

 Another species wnth longer legs and slower in its 

 movements, is some times found in rooms. lulus mul- 

 tistriatus, the thousand-legged w^orm, dark purple 

 brown; 2-4 inches long, and as large as an ordinary 

 lead pencil, is common about the woods. 



Crustaceans — Our species of these are few —The 

 Cray fish — Astacus, is well known and well illustrates 

 the Decapods. Oniscus, a roundish, flat, purplish, 

 14-footed creature, one-fourth inch or less long, living 

 under boards and in damp places, the Tetradecapods. 



