r)18 IIYMENOPTEEA. 



coming to their growth, and passing through all theu' trans- 

 formations, within six or seven weeks from their first ap- 

 pearance. 



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

 he found in my " Catalogue of the Insects of Massachu- 

 setts." Some of these are very interesting in their appear- 

 ance and habits in the catei'pillar 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 Cimhex (Plate 

 VIII. Fig. 12, Cimhex Ulmi). This name was originally 

 given by the Greeks to certain insects resembling bees 

 and wasps, but not producing honey. It therefore ap- 

 plies 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. Iler head ;md thorax are shinino; 

 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 buft'-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 semi- 

 transparent. Her legs are blue-black, and her feet pale 

 yellow. The length of her body varies from three quar- 

 ters to seven eighths of an inch, and her wings expand an 

 inch and three quarters or more. In the manuscript lec- 

 tures of the late Professor Peck, she is called Cimhex Ulmi, 

 because she inhabits the elm. The male is the Cimhex 

 Americana of Dr. Leach, and differs so much from the 

 female, that it might be taken for a different species. His 

 Ijody is longer and narrower than that of the female, and 

 wants tlie white spots on the sides ; and there is a trans- 

 verse, oval hole, filled with a whitish film, behind the tho- 

 rax, which is hardly perceptible in the other sex. His 

 hind legs are very thick; the shins are bowed, and hairy 

 within ; and the first joint of his feet ends with a stout 



