344 ENTOMOLOGICAL SOCIETY 



had always noticed that the trees thus attacked had always been 

 damaged in some way, either by being barked in process of cul 

 tivation or by a branch being broken, or by some unknown cause. 

 He had seen the Chiropachys colon in considerable numbers, and 

 had observed a curious habit in this insect in that both male and 

 female, when about to mate, posture before each other, vibrating 

 the wings. One orchard of about 600 trees of the satsuma plum 

 had been extensively infested by S. rugulosus. The trees died 

 from some perfectly obscure cause, which neither he nor Mr. 

 Woods, of the Division of Vegetable Pathology, had been able 

 to ascertain, and were immediately attacked in great numbers by 

 the Scolytids. 



Dr. Hopkins stated that this beetle will attack, for food, the 

 buds of perfectly healthy trees, and in this way bring about so 

 great an injury as to induce a breeding attack of the same insect. 



This statement was confirmed by Mr. Schwarz, who said that 

 in his opinion the insects of the genus Scolytus will attack per 

 fectly healthy trees. He instanced the case of Scolytus quadri- 

 spinosus on perfectly healthy hickory trees at Detroit, Mich. 

 These were old but perfectly healthy trees, and they were not ap_ 

 preciably damaged by the insect. At Mt. Airy, Ga., he had 

 seen an apparently perfectly healthy peach tree suddenly attacked 

 by Scolytus for feeding purposes. The feeding punctures can 

 always be distinguished from the breeding punctures by the fact 

 that they occur in circular rows. 



Mr. Johnson stated that very few of us are able to ascertain 

 what is a perfectly healthy tree, and that he was certain that in 

 his experience some injury, however obscure, preceded attack by 

 this insect. 



Mr. Ashmead spoke of and illustrated by diagrams some im 

 portant structural characters in the Crabronidae. He had recently 

 devoted some weeks' study to the insects of this family, and called 

 attention to the excellent use which may be made of characters in 

 the mandibles, palpi, antennas, frontal fovea, clypeus, wings, 

 abdomen, pygidium, and legs. He would give generic rank to 

 the subgenera of Fox and Kohl, and would divide the family into 

 four subfamilies. He showed that all of the Fabrician species of 

 Crabro, 17 in number, have been placed in other genera, and he 

 finds himself embarrassed to indicate the type of the genus Crabro. 



