HYMENOPTERA. 409 



their backs, like the Tineae ; certain kinds live within the stems 

 of plants, and devour the pith ; and wheat, in Europe, is said 

 to suffer considerable injury from internal feeders {Cephus 

 pys^mccus) of this kind. When fully grown, most of them go 

 into the ground, and enclose themselves in thin silken cocoons, 

 of an oblong oval shape, coated with grains of earth. Some 

 make much thicker cocoons, in texture resembling parchment, 

 and fasten them to the plants on which they live, or conceal 

 them in crevices, or under leaves and stones on the ground. 

 They generally remain for a long time unchanged in their 

 cocoons, most of them during the winter; are transformed to 

 chrysaHds, of a whitish color, in the spring, and come out in 

 the winged form soon afterwards. Of some kinds there are 

 tu^o broods in the course of the summer, the false caterpillars 

 of the first brood coming to their growth, and passing through 

 all their ti'ansformations, within six or seven weeks from then- 

 first appearance. 



The names of above sixty native species of saw-flies may 

 be found in my " Catalogue of the Insects of Massachusetts." 

 Some of these are very interesting in their appearance and 

 habits in the caterpillar state. In what follows an account 

 will be given of one of the largest species, and of some smaller 

 kinds, that have been found very injurious to cultivated plants. 



Our largest saw-fly belongs to the genus Cimbex. This 

 name was originally given by the Greeks to certain insects 

 resembling bees and wasps, but not producing honey. It 

 therefore applies very well to some kinds of saw-flies, such as 

 the female of this species, which, at first sight, might be mis- 

 taken for a hornet. Her head and thorax are shining black. 

 Her hind body is oval, and of a steel blue or deep violet color, 

 with three or four oval yellowish spots on each side. Her 

 antennae are buff-colored, except at the base, where they are 

 dusky; they are short, and end with an egg-shaped knob. 

 Her wings are smoky brown, and semitransparent. Her legs 

 are blue-black, and her feet pale yellow. The length of her 

 body varies from three quarters to seven eighths of an inch, 

 and her wings expand an inch and three quarters or more. In 

 the manuscr!]pt lectm-es of the late Professor Peck, she is called 

 •52 



