1086 



WALTER H. WELLHOUSE 



All of the flies reared on hawthorns are equal in size to those reared on 

 apple, not small like those reared on the blueberry. Counts were made 



of the infested and the 

 uninfested fruits from 

 a square yard beneath 

 each of ten trees of the 

 three species first men- 

 tioned in the preced- 

 ing paragraph. The 

 counts showed that 

 from 20 to 25 per cent 

 of the samples taken 

 were infested by the 



FlG. 124. CROSS SECTION THROUGH A PINEAPPLE GALL maggots. 



| 



HYMENOPTERA 

 Tenthredinidae 



cerqsi Linn., Caliroa (Pear and cherry slug) 



The sluglike larvae of Caliroa cerasi were in a few localities so abundant 

 that they defoliated a few native hawthorns and injured a number of 

 others. In August, 1918, several trees on the Cornell University campus 

 were completely defoliated, while neighboring trees were untouched by 

 the larvae. 



Sawfly No. 1 



On June 23, 1918, a leaf of Crataegus pruinosa was found with a row of 

 fourteen eggs inserted in the margin. The eggs hatched on June 28, 

 and a row of little green larvae, with large, black heads and many black 

 dots scattered over the body, began to feed gregariously on the edge of 

 the leaf. All of them died within a few days. 



Sawfly No 2 



On May 24, 1918, several medium-sized sawfly larvae, bright green all 

 over, were seen eating separately on the edges of Crataegus punctata 

 leaves. 



Sawfly No. 3 



Sawfly larvae, with red heads and yellow bodies marked with black 

 lines and dots, were found feeding on the leaves of Crataegus punctata 

 in late August, 1918. They were feeding two or three together on a leaf, 

 and fifteen larvae were taken from one tree. When they became about 

 2 centimeters long, on September 1 and 2, they spun brown cocoons on 

 the ground among debris. A tree with ten larvae of the same species 



