i8o 



NEW YORK STATE MUSEUM 



They are more or less gregarious and are found, frequently in 

 considerable numbers, in damp situations, as under logs and stones 

 which have lain on the ground for some time, or under bark or in 

 crevices of trees or in moss. 



Many of the species are world-wide in distribution, and a number 

 seem to prefer the vicinity of human habitations, old greenhouses 

 being a favorite resort. 



The_\ - are commonly known as sow-bugs, pill-bugs, wood lice or 

 slaters and are probably familiar to everyone. In spite, however, 

 of their commonness, little appears to be known of their habits. 

 According to Fitch, their only economic value is as a food for fowls ; 

 but in former times they found much favor as a medicinal agent, 

 being used either dried and pulverized or made into an infusion 

 with " Rhenish wine." 



Family oniscidae 

 Antennae generally long. 

 Body not usually able to be 

 contracted into a ball. Uropoda 

 long and reaching beyond ter- 

 minal segment, which is gen- 

 erally conically produced. 



Oniscus asellus Linn. 



Oniscus asellus Linnaeus. 

 Fauna Suecica, ed.2. p. 500. DeKay. 

 /. c. 1844. p. 51, pl.6, fig.12. Sars. 

 /. c. 1899. v.2, p.171, pi. 75. Richard- 

 sen. /. c. 1901. p.562. 



Flagellum of antennae three 

 jointed; head produced under 

 eyes. 



This and the following species 

 differ from all the rest of our 

 terrestrial Isopods in having the flagellum of the antennae with 

 three joints instead of two. From Philoscia it differs in the greater 

 size and in the lateral angles of the head under the eyes being pro- 

 duced into lobes. 



Fig. 52 Oniscus asellus 



