88 JOURNAL OF ECONOMIC ENTOMOLOGY [Yol. 1 



wingless aphides. In one instance, trunk-bands of the sticky substance 

 known as "Tree Tanglefoot" had been placed upon apple trees in 

 order to catch the crawling woolly aphides. These apple trees were 

 adjoining an orchard of peach and when the crawling lice from the 

 peaches started up the trunks of the apple they were caught in such 

 numbers that the lower borders of the bands were green with a mass of 

 their bodies. The peach trees, now deserted by their parasites, the 

 aphides, soon began to form new leaves and within a few weeks were 

 once more in heavy foliage. The wingless migrating aphides evidently 

 perished in great numbers upon the ground before reaching other food 

 plants; some winged ones safely reached other plants at a distance, 

 where they established new colonies and multiplied until the winged 

 migrants returned again to the peach in the fall. 



Life history records for the early spring generations were secured 

 in the breeding cages. Stem-mothers were kept alive from twenty-three 

 to twenty-nine days from hatching. About eight days passed from 

 hatching to the first molt, four or five days from the first to the sec- 

 ond molt and about the same time from the second to the third. 

 Prom fifteen to seventeen days were passed by the stem-mother from 

 hatching to the birth of the first young. This record was secured by 

 confining single stem-mothers in cages alone, and thus demonstrating 

 them to be parthenogenetic. The first young were born about the time 

 of the third molting by the stem-mother. The maximum number of 

 young secured from one stem-mother in the cages was twenty-six. 



The first young of the second generation from the eggs were seen 

 born in the orchard at Palisade on March 14, 1907, though some were 

 secured in cages as early as March 4. From the birth of the second 

 generation to the first molt was from four to five days and from 

 their birth to their becoming equipped Avith wings was on an average 

 of from eleven to sixteen days. This second generation usually bore 

 the first of the third generation about twelve to seventeen days from 

 their birth and at about the time the first winged lice appeared. Only 

 a portion of the second generation of lice developed wings. From 

 twenty-eight to thirty-three days seemed about the length of life from 

 birth to death of a second generation individual. 



The third generation of agamic aphides were found in the orchard 

 at Grand Junction last season on March 24. These lice are a trifle 

 smaller at birth than the generation born by the stem-mothers. It will 

 be seen that as many as thirteen generations of the green peach aphis 

 may be produced through a single season if the same rate of develop- 

 ment is kept up through the summer to the time when eggs are again 

 deposited in the fall. 



