HYMENOPTERA. 375 



of June, during which period the female lays her eggs upon the 

 common American elm, the leaves whereof are the food of her 

 young. The latter come to their growth in August, and then 

 measure from one inch and a half to two inches in length. They 

 are rather thick, and nearly cylindrical in form, and have twenty- 

 two legs, or a pair to every ring except the fourth. They have 

 a firm, rough, skin, of a pale greenish yellow color, covered with 

 numerous transverse wrinkles, with a black stripe, consisting of 

 two narrow black lines, along the top of the back, from the head 

 to the tail ; and their spiracles, or breathing-holes, are also black. 

 When at rest, they lie on their sides, curled up in a spiral form, 

 and, in this position, look not much unlike some kinds of cockle 

 or snail shells. Like all the false caterpillars of the genus Cim- 

 bex, this insect, when handled or disturbed, betrays its fears or 

 its displeasure by spirting out a watery fluid from certain little 

 pores situated on the sides of its body just above its spiracles. 

 After its feeding state is over, it crawls down from the tree to 

 the ground, and conceals itself under fallen leaves or other rub- 

 bish, and there makes an oblong oval, brown cocoon, very close- 

 ly woven, as tough as parchment, and about an inch in length. 

 In this the false caterpillar remains unchanged throughout the 

 winter, and is not transformed to a chrysalis till the following 

 spring. At length the insect bursts its chrysalis skin, and, by 

 pushing against the end of its cocoon, forces off a little circular 

 piece like a lid, and through the opening thus made it comes forth 

 in its winged form. 



For some years past many of the fir-trees, cultivated for or- 

 nament, in this vicinity, have been attacked by swarms of false 

 caterpillars, and, in some instances that have fallen under my no- 

 tice, have been nearly stripped of their leaves every summer, and 

 in consequence thereof have been checked in their growth, and 

 now seem to be in a sickly condition. These destructive insects 

 agree in their habits and in their general appearance, in all their 

 states, with the pine and fir saw-flies, described by Kollar,* by 

 whose ravages whole forests of these trees have been destroyed 

 in some parts of Germany. It is probable, however, that the 



* " Treatise," pages 340 and 347. 



