230 



Felt (E. P.). Insects and the State. — Separate from N.Y. State Mits., 

 Albany. N.Y.. Bulls. 219, 220 (15th Kept, of Director, 1918), 

 1921, 7 pp. 



The importance of the insect fauna of the United States is discussed, 

 and the number of species represented in, and the value of, the New 

 York State collection are described. The natural resources of the 

 State offer large fields of investigation to the entomologist. It is 

 remarked that the occasional outbreaks of previously almost unknown 

 and obscure species, such as the importance assumed by Pyrausta 

 nubilalis (European corn borer) — a genus hitherto considered of little 

 or no economic importance — illustrates in a convincing manner the 

 need for studying some of the comparatively unknown or neglected 

 groups of insects in view of possible future emergencies. 



Theobald (F. V.). The Woolly Aphid of the Apple and Elm {Erio- 

 soma lanigera, Hausm.). Part I. — Separate from //. of Pomology 

 [sine loco], ii, no 2 [n.d.], 20 pp., 8 figs. [Received 10th March 

 1921.] 



The introduction and early history of Eriosoma lanigerum, Hausm., 

 in Britain is discussed. As this Aphid is found on wild crab-apple 

 in both America and Europe, the author is inclined to doubt whether 

 it is an introduced species in the latter continent. 



For many years the life-cycle in Britain was assumed to be known, 

 but the information was imperfect, and the fact that it migrates from 

 the elm to the apple in July alters the correct time for spraying and 

 explains many past failures in treatment. Eriosomatines differ from 

 most Aphids in laying but a single egg, both male and female being 

 produced on the primary food-plant by the alate autumn or return 

 migrants. 



The correct life-cycle of E. lanigerum with its normal double food- 

 plant has been described in America [R. A.E., A, v, 476]. The author 

 has observed the cycle to be the same in Britain. That is to say, 

 the primary food-plant is the elm {Ulmus), where the egg-stage is 

 found in winter on the wood of suckers and in crevices of the bark 

 near the ground. The eggs hatch from .early March to April, and 

 the larvae wander about until they settle on a tender, unfolding leaf. 

 They grow slowly at first, but by May the majority have become 

 stem-mothers, ensconced in a curled leaf. This curling must not be 

 confused with the elm-leaf curl caused by E. nlmi, E., which migrates 

 to the roots of Ribes and becomes E. fodiens. In June and early 

 July the apterae in the elm-leaf rosettes transform to nymphs, and 

 in July assume wings and migrate from the elm. These are the summer 

 migrants (called in America spring migrants). From this time until 

 September no stage of this Aphid seems to occur on elms. These 

 alatae represent a third generation. They are viviparous, and when 

 transferred to the apple, produce living young that become typical 

 woolly Aphids. This, however, will not happen in every case experi- 

 mentally. During September a certain number of woolly Aphids on 

 the apple become nymphs, and form the return alate females that 

 migrate during September and October, many of them straying, but 

 some settling on elms to continue the life-cj^cle. These return migrants 

 can easily be distinguished by their shorter antennae. On the elm 

 they give rise to living young that develop into the arostrate, oviparous 

 males and females, and these produce the few ova from which the 

 life-cycle starts. 



