150 MANUAL OF VEGETABLE-GARDEN INSECTS 



feed at first on various wild plants, preferring solanaceous 

 weeds. As soon as potato and tomato ])lants are available, 

 the beetles migrate to them and deposit their eggs usually on 

 the underside of the leaves in clusters of six to ten. Each 

 egg is about -^ inch in length, smooth, oval and yellowish 

 in color. The eggs hatch in about two weeks and the young 

 larvae at first feed in a row side by side, beginning at the edge 

 of the leaf and moving backward as they devour the tissue. 

 When mature the larva is about ^ inch in length with the head, 

 thoracic shield and legs black and the body yellowish. The 

 body of the larva is kept moist and sticky by a secretion and 

 is usually covered with a coating of excrement. The grubs 

 become full-grown in about two weeks and then enter the ground 

 where they construct earthen cells lined with a gelatinous 

 secretion from the mouth. The pupal period occupies about 

 two weeks. There are said to be two generations annually. 

 The three-lined potato beetle has never been reported as 

 a very important pest but it may occasionally become trouble- 

 some when conditions are favorable for its development. It 

 may be controlled by spraying with arsenical poisons as recom- 

 mended for the Colorado potato beetle. 



References 



Harris, Insects injuriotis to vegetation, pp. 95-96. 1841. 

 Fitch, 10th Kept. N. Y. State Ent., N. Y. State Agr. Soc, 24, pp. 441- 

 447. 1864. 



The Potato Aphis 



Macrosiphum solanifolii Ashmead 



Although the potato aphis is generally distributed through- 

 out the United States and southern Canada, injurious out- 

 breaks have been reported only from Maine, Connecticut, 

 New York, New Jersey, Pennsylvania, Ohio, Illinois, Iowa, 

 Kentucky, Maryland and Virginia and the provinces of Ontario, 



