HYMENOPTERA. 371 



by the gall-flies, and inhabited by their young; — the clay cells of 

 the mud-wasp, plastered against the walls of our houses, each 

 one containing a single egg, together with a large number of liv- 

 ing spiders, caught and imprisoned therein solely for the use of 

 the little mason's young, which thus have constantly before them 

 an ample supply of fresh provisions ; — the holes of the stump- 

 wasp, stored with hundreds of horse-flies for the same purpose ; 

 — the skill of the leaf-cutter bee in cutting out the semicircular 

 pieces of leaves for her patchwork nest; — the thimble-shaped 

 cells of the ground-bee, hidden, in clusters, under some loose 

 stone in the fields, made of little fragments of tempered clay, 

 and stored with bee-bread, the work of many weeks for the indus- 

 trious laborer ; — the waxen cells made by the honey-bee, with- 

 out any teaching, upon purely mathematical principles, measured 

 only with her antennas, and wrought with her jaws and tongue ; — 

 the water-tight nests of the hornet and wasp, natural paper-makers 

 from the beginning of time, who are not obhged to use rags or 

 ropes in the formation of their durable paper combs, but have 

 applied to this purpose fibres of wood, a material that the art of 

 man has not yet iDeen able to manufacture into paper ; — the her- 

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

 galleries, compared wherewith, if the small size of the laborers 

 be taken into account, the efforts of man in his proudest monu- 

 ments, his pyramids and his catacombs, dwindle into insignifi- 

 cance. 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 Hymen- 

 optera which are actually or seriously injurious to vegetation. 

 Those which 1 propose now to describe are not provided with 

 venomous stings, and, consequently, are to be included among 

 the Piercers. 



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

 found on the leaves of plants, and live almost entirely on vege- 

 table food. They are the least active of the Hymenoptera, are 



