90 ASSOCIATION OF ECONOMIC ENTOMOLOGISTS. 



the bark was thickly covered with this early summer brood. Some 

 were seen upon both upper and lower leaf surfaces and many at this 

 date had well-developed scale coverings alread}^ secreted over them. 

 Many oval eggs were found, shoAving the females to be oviparous 

 rather than vivij^arous, as in the case of its close neighbor, the San 

 Jose scale. The exact time required for hatching is evidently quite 

 short, for beneath these female scale coverings and along with the 

 small clusters of eggs are usually also to be seen the minute yellowish- 

 orange-colored and newly hatched young. In western Colorado it is 

 probable that at least three and perhaps four broods are developed 

 throughout the season, including those living through the winter; 

 and male insects are seemingly produced throughout the greater part 

 of the summer season. 



Earl}" in June and again in the month of August adults of an inter- 

 esting hymenopterous parasite were observed; specimens were deter- 

 mined as Prospalta aurantii How., which, according to Doctor 

 Howard, is entirely new to this species. The adult parasites emerging 

 left the small round circular apertures which I found in the centers 

 of so large a percentage of the larger scales through the spring and 

 summer. Adults and larva? of the more common lady beetle, Chilo- 

 corus hivulnerus Muls,. also played some part in the destruction of the 

 scale. 



. A survey of the orchard section of western Colorado showed the 

 scale's distribution to be quite general. The growers about the region 

 of Grand Junction have thus far been most successful in withstand- 

 ing the usual destruction occasioned by pear blight, accounting at 

 this time for an extensive pear acreage. At this place the spraying 

 experiments were carried out and upon pear trees previously un- 

 sprayed and consequently badly incrusted with the scale at the outset 

 of the tests. 



In all about 200 pear trees were included, and the insecticides used 

 were principally those known to have been more or less successfully 

 used against the San Jose scale. The sprays and their formula? were 

 as follows: 



(1) '' Rex " lime and sulphur dip, diluted 1 to 11 with cold water. 



(2) "Rex" lime and sulphur dip, diluted 1 to 8 wnth cold water, 

 with 15 pounds lime added per 50 gallons of spray. 



(3) Lime-sulphur-soda wash, prepared without use of external 

 heat and boiled by the soda and heat of the slaking lime — 30 pounds 

 lump lime, 15 pounds sulphur, and 5 pounds caustic soda per 50 gal- 

 lons of water. 



(4) Lime-sulphur wash, prepared in usual way by boiling 45 min- 

 utes with external heat, and composed of 15 pounds lime and 15 

 pounds sulphur per 50 gallons of water. 



