SAW-FLIES. 515 



yet been able to manufacture into paper ; — the herculean 

 labors of ants in throwing up their hillocks, or mining their 

 galleries, compared wherewith, if the small size of the la- 

 borers be taken into account, the efforts of man in his proud- 

 est monuments, his pyramids and his catacombs, dwindle 

 into insignificance. These are only a few of the objects 

 deserving of notice among the insects of this order; many 

 others might be mentioned, that would lead us to observe 

 with what consummate skill these little creatures have been 

 fashioned, and how richly they have been endowed with 

 instincts that never fail them in providing for their own 

 welfare, and that of their future progeny. 



Comparatively speaking, there are not many of the Hy- 

 menoptera which are actually or seriously injurious to vege- 

 tation. Those which I propose now to describe are not 

 provided with venomous stings, and, consequently, are to 

 be included among the Piercers. 



Such are the saw-flies (TENTHREDiNiDiE), insects that 

 are found on the leaves of plants, and live almost entirely 

 on vegetable food. They are the least active of the Hymen- 

 • optera, are sluggish in their habits, fly heavily and but little, 

 and do not attempt to escape when touched. Most of them 

 are rather short and somewhat flattened. They have a 

 broad head, which, seen from above, appears transversely 

 square; The hind body is not narrowed to a point where 

 it joins the thorax, but is as broad as the latter, and is closely 

 united to it. The antennae are generally short; but they 

 vary much in form; in many species they are thread-like 

 and slightly tapering; in some, thickened or knobbed at 

 the end; more rarely, they end suddenly with a few very 

 small joints, much more slender than the rest; they are 

 feathered in some males, and notched in the other sex ; and 

 sometimes they are forked, or divided into long branches. 

 Their wings cross and overlap each other, and cover the 

 back horizontally when closed. But the most striking pe- 

 culiarity of these insects consists in the double saws where- 



