374 INSECTS INJURIOUS TO VEGETATION. 



in their cocoons, most of them during the winter ; are trans- 

 formed to chrysalids, of a whitish color, in the spring, and come 

 out in the winged form soon afterwards. Of some kinds there 

 are two broods in the course of the summer, the false caterpillars 

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

 their transformations, within six or seven weeks from their 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 hab- 

 its 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 mistaken 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 yel- 

 low. The length of her body varies from three quarters to seven 

 eighths of an inch, and her wings expand an inch and three quar- 

 ters or more. In the manuscript lectures of the late Professor 

 Peck, she is called Cimbex Ulmi^ because she inhabits the elm. 

 The male is the Cimbex Americana of Dr. Leach, and differs so 

 much from the female, that it might be taken for a different species. 

 His body is longer and narrower than that of the female, and 

 wants the white spots on the sides ; and there is a transverse, oval 

 hole, filled with a whitish film, behind the thorax, which is hard- 

 ly 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 hook, curved inwards. He often measures 

 an inch in length, and his wings expand about two inches. 

 These insects appear from the latter part of May to the middle 



