THE HyMENOPTERA OF MINNESOTA 161 
worm, eat the leaf entire. When full grown, the larvae make an 
oval parchment-like cocoon which may be attached to host plant or 
just below the surface of the ground. 
Several species work on pine, others on strawberries, one on 
alder—on Cornus, oak, maple, etc. Two attack willows. One species 
is found on butternut. Another bores into the leaf stem of sugar 
maple. At least one species is known to work on cranberry. Still 
others make galls and two or more are known to be leaf rollers. One 
feeds on poison ivy, and another feeds on sweet potato. 
The family is referred to as “sawflies” because the females have 
saw-like ovipositors, the ovipositor represented by a pair of stylets, 
each serrate on outer margin. 
Fig. 38. Tenthredella lobata Norton: female. 
The larch sawfly, Lygaeonematus erichsonii is a menace to the 
tamaracks of the northern part of the United States and Canada. 
The effect of the attacks of the pear and cherry slug may be so 
severe as to cause the leaves of these trees to brown and fall to the 
ground in the middle of the summer. Fortunately, this pest of the 
orchardist is easily destroyed, yielding readily to any of the arsenical 
insecticides, to hellebore or pyrethrum, to dusting with air-slaked lime, 
or even with road dust. 
