176 



THE CANaOIAN horticulturist. 



DAXGER TO OUR SHADE TREF.S. 



During the past few days evidence 

 has been accumulating of the rapid in- 

 crease of an injurious insect which 

 promises to become a serious injury to 

 the maple trees on our streets. Just 

 now on the trunks of many of these 

 trees the empty pale-brown chrysalids 

 of this insect may be found protruding 

 about half an inch. These chrysalids 

 are so delicate in their texture that a 

 touch will crush them, and if not in- 

 terfered with otherwise the >yinds will 

 detach them, and they will disappear 

 within a few days. 



I will endeavor, in as few words as 

 possible, to trace the life history of this 

 insert, which, with the aid of the 

 accompanying illustration, will easily 

 be understood. 



The perfect insect (shown at c in the 

 figure) is a very pretty, clear winged 

 moth, resembling a wasp, which, when 

 its wings are expanded, will measure 

 about three-quarters of an inch across. 

 It is known to entomologists as the 

 maple Egerian, jEger'ia acerni. The 

 wings are transparent and decorated 



! with bluish-black markings ; the head 

 is dee[) orange ; the antennae, bluish- 

 black ; the thoi-ax yellow, and the ab- 

 domen bluish-black, banded with golden 

 yellow, and terminating in a tuft of 

 brilliant orange-red haii-s. 



The female lays her eggs on the bark 

 of the trees chiefly affecting the soft or 

 red maple, .-leer rubrum, although it was 

 occasionally found also on the other 

 two species of maple used for street 

 planting, namely, the suyar maple, 

 Acer saccharlnum, and the silver-leaved 

 maple, Acer dasycaiyuiu. In a few 

 days small larvae hatch from the eggs, 

 and these at once penetrate through 

 the bark and begin to feed upon the 

 inner portion and sap-wood of the tree, 

 making an irregular burrow which is 

 packed with the castings of the larva 

 mixed with minute woody fragments. 



When full grown it is about three- 

 fourths of on inch long, with a small 

 yellow head and a white or yellowish- 

 white body, which is darker on the 

 hinder segments. Early in the follow- 

 ing spring, when full gi-own, it a})pears 

 as seen at a. It then eats its vvay 

 nearly through the bark, leaving but a 

 very thin film unbroken, when it re- 

 tires within its burrow, and, having en- 

 closed itself within a loose silky cocoon 

 (see h in the figure) changes to a brown 

 chrysalis. A short time before the 

 moth is ready to escape the chrysalis 

 works its way out of the cocoon, and, 

 wrigging itself forward, pushes against 

 the filmy layer of bark, ruptures it, and 

 protrudes half-way or more from the 

 opening (as seen at d), when the im- 

 prisoned moth shortly ruptures the 

 chrysalis case and escapes. 



It is while in the larval stite that 

 this insect is destructive. Many of 

 the maple trees on our streets, and 

 some of those in the Park, are being 

 injured, and where the insect is allowed 

 to multiply it is likely that it will, 



