16 4 INSECTS. 



hatched. The red and green swellings so common on 

 the leaves of various willows, and woody excrescences 

 found upon the stems, are the production of species of 

 the Tenthredinidse. 



It has been said above (p. 154} that while the larvae 

 of the rest of this order are footless grubs, incapable of 

 seeking their own food, or in any way providing for 

 their own wants, the larvae of the Tenthredo family are 

 active, and are left to " make their own living." In form 

 and general appearance they closely resemble the cater- 

 pillars of moths. Like them, they have the six true 

 legs (i.e., legs which answer to those in the perfect 

 insect), and, in most eases, the " false legs." These 

 false legs differ from those of the moths, in being with- 

 out the circle of hooks with which the false legs of the 

 Lepidoptera are furnished. The false legs of the 

 Tenthredo caterpillar differ in number also from those 

 of the Lepidoptera, which never have more than three 

 pairs of true legs on the thorax, four pairs on the- 

 abdomen, and one pair at the tail. The Tenthredo ha& 

 three pairs of true legs, five, six, or seven pairs of 

 abdominal legs, and one pair at the tail, except in two- 

 genera, where the false legs are altogether wanting. The 

 examination, therefore, of the legs will at once enable 

 the student to distinguish between the Hyinenopterous- 

 and the Lepidopterous caterpillar. 



The hirvee are chiefly green, sometimes yellow, with 

 spots and tubercles, and have many of the habits of 

 true caterpillars, for instance, of coiling themselves up, 

 feigning death when alarmed, throwing out a silken 

 rope by which to descend from one branch to another, 

 &c. Some roll up the leaves of trees, and fastening 

 them in that position by means of silken threads, thus 



