380 ARTICULATES : INSECTS. 



across each ring ; under surface yellowish. After the 

 last moulting they become yellow, burrow in the ground, 

 form small oval cells lined with silk, and in about a fort- 

 night come forth in the perfect form and lay their eggs 

 for a second brood, which are not transformed to flies 

 until the next spring. 



The Genus Lophyms contains the Fir-tree Saw-Fly, 

 Fig. 280. L, abietis, Harr., which feeds 



upon the fir-tree. The male 

 is about one fourth of an inch, 

 and the female about three 

 tenths of an inch long. 



The Genus Cimbex contains 



Saw-Fly (enlarged), L. 'alietis, Harr. large SaW-FHcS. The Elm SaW- 



Fly, C. ulmij Peck, is about three fourths of an inch 

 long, head and thorax shining black, abdomen steel- 

 blue, with three or four oval yellowish spots on each 

 side ; legs blue black, feet yellow. The male has the 

 body longer, narrower, and no spots on the sides, and 

 appears so different from the female, that it has been 

 described as distinct. These flies appear in the latter part 

 of May and June, and the female lays her eggs on the 

 elm, upon the leaves of which the larvae feed. These come 

 to their growth in August, and then are an inch and a 

 half to two inches long, thick, and covered by a firm skin, 

 with numerous transverse wrinkles ; color pale greenish- 

 yellow, with a black stripe of two black lines from the 

 head to the tail, and black spiracles. When at rest, they 

 lie upon the side, and look somewhat like a, snail-shell. 

 It makes an oblong cocoon, very closely woven, and 

 tough, about an inch long, in which it remains unchanged, 

 under leaves and rubbish, till the next spring. 



