268 EXPERIMENT STATION RECORD. 



rod extent, respectirel3\ On August 20, 1898, the wasps were seen 

 eating the cabbage worm and also the codling moth. The apple trees 

 were loaded with fruit and were almost free from the codling moth, 

 which was considered remarkable in view of the fact that apples in 

 that region are usually badly infested. The owner had never been 

 under the necessity of spra\nng these trees. The author collected a 

 few larvae of the codling moth and scattered them near the })urrows of 

 the wasps, and the}^ were greedily seized upon by the latter. As a rule, 

 the wasps cover the opening of their burrows upon leaving them. In 

 an area 18 in. square 39 closed burrows were found with a depth of 

 from 4 to 8 in. and a diameter of i in. The burrows were for the most 

 part un branched, and at the terminus was to be found sometimes a sin- 

 gle cocoon and at other times from 1 to .3 larvae of the codling moth. 

 The author describes the method by which the larva of the wasp feed 

 upon the codling moth. 



The apple plant louse, J. B. Smith {New Jersey Stm. Bui. lJf3, j)I>- 

 ^3., Jigs. S2). — From observations made by the author during the past 

 3 years, it is concluded that the apple plant louse upon apple trees in 

 New Jerse}" has no alternate food plant and, therefore, no "'migrant" 

 or "return migrant" forms. The species is Ajyhls mail, and ma}' be 

 distinct from the one which has been described by other authors as 

 migrating from the apple tree to other food plants. On November 1, 

 1898, the author began observations upon a tree which was badly 

 infested with this species. At this date many eggs had already been 

 laid, and it was observed that both sexes of the insect were wingless. 

 When the plant lice began to develop in the spring of 1899, daily 

 observations were made for a time and specimens were collected at 

 frequent intervals during the season. 



The author reports in detail his observations upon the appearance 

 and habits of the various generations which occur during a season, 

 noting the anatomical characters by which the different generations 

 ma}^ be distinguished. The life history of the apple plant louse, as 

 observed by the author, may be summarized as follows : The species 

 hatches from the egg as soon as buds develop in earliest spring. The ' 

 stem-mother becomes mature and begins to reproduce about 15 days 

 later. After another period of 9 or 10 days the second generation 

 becomes mature, and it was observed that about three-fourths of this 

 generation were winged. Two weeks later the third generation becomes 

 developed, and about one-half of the individuals of this generation are 

 winged. During the whole year there are 7 generations of partheno- 

 genetic females, ])ut no winged individuals are to ])e found except in 

 the second and third generations. The winged forms leave the trees 

 upon which they have developed, fly to other apple trees, and in this 

 way bring al)out the wide distribution of this species. The individuals 

 which fly from one tree to another arc not to be regarded as repre- 



