lo CRUSTACEANS. 



CASE PoRCELLio SCABER (Zrt/r.).— No. 3. Specimens (12); 4. Enlarged figure 

 Nos. of ditto. 



3. 4- 



Porcellio scaber (natural size). Antenna of Porcellio scaber. 



External antennae, seven-jointed. Rougher than Onlscus asel- 

 lus, and browner and more varied in colour. There are several 

 species, two of which have the power 'of rolling themselves up 

 like a ball, the rest have not. 



Nos. Armadillo vulgarls (Zm«.).— 5. Specimens (12) ; 6. Enlarged figure of 

 5~7- ditto ; 7. Enlarged figure of insect rolled up as a ball. 



Armadillo vulgaris rolled up as a ball. Armadillo vulgaris. Antenna of Armadillo vulgaris. 



(natural size). 



In this genus, as in Porcellio, the last elbow of the outer an- 

 tennae has two joints instead of three, and the insect has the 

 power of contracting itself into a ball. It is larger, smoother, and 

 of a more uniform slatey-blue colour than the others. Its habits, 

 and the mischief it does, are much the same as those of the com- 

 mon Oniscus, and the remarks made on it also apply to this and 

 the species of PorcelHo. 



