92 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Owing to the lateness of the season and the press of other work 

 in the fall of 1909, very little in the way of biological studies of this 

 new species could be accomplished, although several unsuccessful 

 attempts were made to carry the larvae through to the adult stage. 



OBSERVATIONS ON THE PEACH AND PLUM SLUG IN 1910. 



In the spring of 1910 a careful watch was kept for the insects, and 

 the earliest recorded observation was made on April 1, when two 

 adult sawflies were observed on a peach tree. This is probably very 

 near to the first date of appearance of the species, since careful 

 search did not reveal larvae until April 7. On this date 6 larvae 

 one-third grown and 5 eggs were found. Morgan (1. c.) states that 

 the adults may be seen at any time from the middle of March until 

 cold weather. His observations were made at Baton Rogue, La., 

 about 130 miles south of Tallulah, La. 



On April 21 several larvae were taken, feeding on the leaves of a 

 plum tree in the laboratory yard. From this time on, and under 

 generally warm, dry weather conditions, the infestation increased 

 gradually until April 24, when a severe frost killed all but a very few 

 of the immature stages, including all of those directly under observa- 

 tion on the trees. Following the freeze came a long, cold drought, 

 unbroken until May 18 and foUowed by about a week of daily heavy 

 rains. This, in turn, was followed by more cold weather. From the 

 middle of June until the first week in July there were almost daily 

 heavy rains. This combination of unfavorable weather conditions held 

 the species in check to such an extent that it was difficult to find it in 

 any stage. On July 12, 7 full-grown larvae and a number of small 

 larvse were found, the latter probably hatched since the last rain. 

 Xone between these two stages was observed. After this time fre- 

 quent observations were made and considerable rearing work done. 



While before the freeze of April 24 all of the trees in the laboratory 

 yard had suffered about equally from the depredations of the insects, 

 from this time until about the middle of August the infestation was 

 confined almost entirely to two trees, which stood within a few feet 

 of the north side of the house, and which were further sheltered by a 

 large pear tree and a persimmon tree. For a long time the injury 

 was practically confined to the lower branches close to the house 

 and under the pear and persimmon trees. But as the season advanced 

 and the supply of suitable leaves in those locations failed the 

 infestation spread over these two trees and to the other peach trees 

 and the plum trees in the yard. Whether it is the normal habit of 

 the species to confine its work as closely as possible to its breeding 

 place, or whether the concentration noted was due to the fact that 

 the adults which survived the freeze sought a sheltered location for 

 depositing their eggs, is not quite clear. However, the earlier 



