662 EXPERIMENT STATION RECORD. [Vol. 87 



dm and at no very distant date may become entirely adapted to this native 

 trea The species is liable through Importations to gain a foothold in any pear- 

 growing region, for, as recently as 1916, skins have been collected on seedling 

 nursery stock. . . , 



" The fall seiuparous migrants leave the pear roots upon which they have 

 developed and fly to elm trees to deposit the sexes on the trunks and limbs. 

 These migrants settle on Ulmtts americana and U. campestris. The latter tree 

 Is distinctly preferred ; in fact, no perfect galls have been produced on the 

 former. The sexed female after mating deposits a single egg in a crack in the 

 bark or underneath a bud scale. . . . From this egg hatches the young stem 

 mother which ascends a trunk or limb and seeks an expanding leaf. In 1916 

 hatching commenced March 23 and extended until April 18, the majority hatch- 

 ing during the first two weeks of April." 



The newly-hatched stem mother settles on the underside of the elm leaf near 

 the midrib, generally not far from the base. "-After the young aphid has fed 

 for a very few days, the leaf begins to curl around it, and the curling and twist- 

 ing become more pronounced as the Insect grows, so that by the time it has 

 reached the third Instar the leaf In the form of a gall has completely closed 

 around It" Following upon the maturing of the stem mother the galls grow 

 very rapidly and change their shape. " The possibility of the second generation's 

 wingless forms leaving the parent gall and founding new galls should not be 

 overlooked ; yet the observations made indicate either that no such movement 

 exists or that it Is uncommon." 



In 1916 nearly every gall examined contained winged forms by the fourth 

 week In June, large numbers of the earlier galls had been vacated by July 10, 

 and by the end of July hardly a gall with living Inmates could be found. Spring 

 migrants were observed resting on pear foliage and actively crawling up and 

 down the lower part of the pear trunks, young deposited by them were taken in 

 spider webs at the base of pear trees, and it appears that the young are nor- 

 mally deposited on pear trunks at or near to the soil surface. Spring migrants 

 when placed in Petri dishes with pieces of pear roots on wet sand deposited 

 young which readily settled and fed upon the roots and which precisely resem- 

 bled in structure the newly-born larvae of the pear-root aphis. The young de- 

 posited by the spring migrants readily fed on pear stocks of Kieffer, French, 

 and Japanese varieties, but like the root-dwelling larvae absolutely refused to 

 feed upon apple roots and fed only in very rare Instances upon roots of the 

 quince. 



The life history account is accompanied by a diagram of the complete life 

 cycle of the species. A list of ten titles cited Is appended. 



The aphid of tea, coflEee, and cacao (Toxoptera coffeae), F. V. Theobald 

 (Bui. Ent. Research, 7 (1911), No. ^, pp. SS7-^42, figs. S). — A summarized ac- 

 count of T. coffecB. 



Observations on Lecanium comi Bouche and Physokermes picese Schr., 

 F. A. Fenton (Canad. Ent., ^9 (1917), No. 9. pp. S09S20, pi. 1, figs. IS).— A. 

 report of biological studies of the European fruit lecanium (L. comi) and the 

 spruce scale (P. picece) at Mndison, Wis. 



L. corni, observations of which in New York by Sllngerland (E. S. R., 6, p. 

 1004) and by Lowe (K S. R., 9, p. 71) have been noted, now occurs throughout 

 most of the United States. It has a wide variety of host plants, a list here 

 given Including 36 genera, representing 21 families. In spite of the wide range 

 of Its host plants and Its general distribution this insect seldom becomes of 

 economic importance, although serious outbreaks of it have been recorded, it 

 having occurred In New York In destructive abundance on the plum and In 



