WOOLLY APHID ON ELM AND JUNEBERRY. I99 



This, then, is the destined summer residence of the insect; — 

 the little thing whose mother, grandmother and great grand- 

 mother grew up in the curl of a high swinging elm leaf, creeps 

 under ground and sips Juneberry sap in the dark. 



There is, perhaps, no bird migration more remarkable than 

 the flight of a migratory aphid and the histories of many species 

 of this family of insects have the thrill of a dramatic tale of 

 adventure. 



The summer colonies of our aphid of elm and Juneberry, luce 

 their spring antecedents, are composed only of females, the first 

 generation being wingless and the body whitened by the secre- 

 tions of the wax glands. 



In the fall a generation of winged females is developed 

 among the underground forms. These are the fall migrants and 

 in appearance they are practically like the spring migrants. 

 These leave the Juneberry and take flight to some American 

 Elm. 



Alighting on the bark, they seek a convenient crevice and give 

 birth to minute young, part of which are egg-laying females 

 and part males, — this being the only time in the life cycle of 

 this insect that either of these forms appear. These tiny "true 

 sexes" have no functional mouth parts, — their chapter in the 

 life history being concerned merely with mating and providing 

 for the deposition of the overwintering egg. Each female lays 

 but a single egg which nearly fills her small body. 



The egg is the closing page of the life cycle for the fall, and 

 the opening one for the spring; because it is from this overwin- 

 tering egg that the stem-mother hatches at the time of the 'dutsl- 

 ing leaf buds, in season to form the curl of the elm leaf for the 

 spring habitation used by her and her numerous progeny. 



Natural Enemies. 



There are several predaceous insects which frequent the elm leaf curls 

 of this aphid. In Maine the most common ones are a capsid (Cainpto- 

 brochis nitens), the flocculent larva k3f a coccinellid, and syrphus mag- 

 gots. Some years these greatly reduce the numbers of this elm^ pest. 



Preventive and Remedial Measures. 



In a state vi^here both elms and Juneberries abound as they do in 

 Maine, we must expect ithis aphid to occur both in the curl of tne 

 leaves of the former and on the underground stems of the latter. 



