ECONOMIC IMPORTANCE OF S0WBUG8. 21 



very clnll. Followino- the first stage of the molt the anterior se<2:- 

 iiients eoininence to h)osen and are slid forward. The dorsum of 

 the third and fourth thoracic se^jnients is loosened l)efore the legs 

 of these segments are released. From then on the last two pairs of 

 legs in the very young and the last three in later stages are used to 

 hold the animal in position. The anterior legs are not available for 

 use for some time after they are free. The antennae are withdrawn 

 last. 



Regeneration of parts takes place in the antennae and legs. Several 

 times individuals with aborted members were noticed. These latter 

 W'ould gradually attain full length, then budding of the succeeding 

 segment would be noted and finally this member would be normal. 

 The regenerated part is Avhite for some time. 



REMEDIES. 



In the treatment of sowbugs poisoned baits are standard remedies. 

 The great fondness of sowbugs for potatoes long ago led to these 

 being used, poisoned either with I*aris green or London purple. 

 The potatoes are sliced and a thin covering of pow^der applied. 

 Sprinkling the soil around an injured plant Avith Paris green, or 

 dusting the same under boards and other haunts of the sowbugs is 

 also very effective. If the sowbugs are injurious in a garden patch — 

 after treating the ordinar}^ haunts — it is best to keep the ground well 

 broken and raked to prevent clodding and cracking, wdiich gives them 

 protection. Old boards, cans, and rubbish should not be allowed to 

 accumulate. Such precautions will tend greatly to prevent any 

 great damage or annoyance. 



Carbon bisulphid has been recommended for the treatment of sow- 

 bugs in greenhouses and dwellings, but no special experiments along 

 this line have been tried by the writer. 



PORCELLIO LiEVIS Latr. 



Pot'cellio lac is Latr. is a lighter colored sowbug than the preced- 

 ing, and does not roll up in a ball when disturbed, but instead runs 

 rapidly away to cover. The only definite point in favor of consid- 

 ering it as naturally a plant feeder was the discover}^ of one dead 

 specimen under cotton dusted w ith Paris green. It was found, how- 

 ever, that the best way to keep this species alive in the laboratory 

 w^as to furnish it with fresh cotton leaves and loose mixed soil. 

 Sowbugs of this species were not found far from the barns, and were 

 n.ot numerous in the laboratory cotton patch. They were generally 

 under moist, dark objects and seemed to prefer damp wood piles. 

 Several were found with Armadillidium in crevices and in trees at 

 various heights. One Porcellio was found in the skeleton of a car- 

 abid beetle, which was entirelv eaten out. In numerous cases this 



