18 The European Elm Scale 



side of the lower branches and immediately washed them all off with 

 the garden hose; throughout the summer he followed the same. plan, 

 washing the bark of all accessible limbs and the undersides of the 

 leaves occasionally with the strong stream from the garden hose. 



The result of this treatment was so good that the trees appeared 

 entirely healthy and made a vigorous growth throughout the summer. 

 CJnsprayed trees across the street were badly infested and turned pre- 

 maturely yellow. An examination in the winter following disclosed 

 a few hidden dead female scales. A few scattered larvae were 

 to be found about the buds and leaf sears. On a few branches hiber- 

 nating larvae were found in considerable numbers along the bases of 

 projecting ridges of cork. In this instance the escape of the few 

 female insects and the consequent number of hibernating larvae were 

 due in large part to the extreme roughness of the bark. 



LOT III 



Two American elms and fourteen young cork elms all recently 

 planted. They range in height from four to sixteen feet. Winter 

 larvae were exceedingly numerous, trees completely infested. Well 

 sprayed once late in the afternoon of Feburuary 11th, 1907. The 

 lime-sulphur used had been well-cooked with steam ; it was, however, 

 the remainder of a barrel left after spraying a number of other trees 

 and was rather thick with sediment. 



The trees were examined about three weeks after spraying, on 

 March 6th, 1907. The material chosen for this examination consisted of 

 twigs about one-quarter inch in diameter, thoroughly sound and green, 

 taken from different parts of several trees. These twigs had all been 

 well coated with the lime-sulphur; the wintering larvae between the 

 projecting ridges of cork were all still more or less encrusted with it. 

 A count of one thousand hibernating larvae showed that 330 were dead 

 and 670 were living. Dried and shrunken larvae were counted as dead. 

 Those plump, of normal color, and full of the usual clear-brown body 

 fluids were considered alive; most of them gave further evidence of 

 life by moving legs or antennae. Many of them with backs totally 

 encrusted with lime-sulphur moved legs and antennae when lifted 

 from the bark on the point of a needle. 



On May 1st, 1907, these trees were well covered with living Gossy- 

 paria, hibernating larvae, newly moulted females, and male cocoons. 

 Ants and flies were attracted in large numbers by the excreted honey 

 dew. The two trees worst infested were young American elms about 

 sixteen feet in height. The undersides of many of the branches were 

 literally crowded with different stages of the insect in question. These 



