December 23, 1898.] 



SCIENCE. 



917 



SOCIETIES AND ACADEJIIES. 



ENTOMOLOGICAL SOCIETY OF WASHINGTON, 

 DECEMBER 1, 3 889. 



Under the head of election of officers all of 

 the ofiBcers serving during 1898 were re-elected 

 for the year 1899. E. Dwight Sanderson, of 

 College Park, Maryland, was elected an active 

 member. 



Under the head of exhibition of specimens 

 and short notes, Mr. Schwarz spoke of the 

 ScolytidjB of Arizona, showing that thirty two 

 species had been collected in southern Arizona 

 by Mr. Hubbard and himself. Nineteen of 

 these species occurred in the pine region ; seven 

 in the oak zone, and six in the lowest region. 

 Of the whole number, only ten species proved 

 to be identical with previously described forms, 

 and all but one of the identified species belong 

 to the pine regions. 



Dr. A. D. Hopkins, by invitation of the 

 Chair, presented some notes on Scolytidai with 

 especial reference to habits. He showed the 

 male of Hypoihenomus, which is relatively of 

 extremely small size and is rare. H. dissimUis 

 breeds in dead twigs where the larvas consume 

 a kind of ambrosia. In the first lot of eggs de- 

 posited only one is a male and this apparently 

 is the only male in the number of successive 

 bi'oods developed as a product of a single female. 

 There is, therefore, intense polygamy and in- 

 and-in breeding. Further notes were given on 

 the habits of Cnesinus strigicollis and Pityoph- 

 thorus minuHssimus. He showed that the larvaj 

 of Scolytids are sometimes killed by not very 

 severe freezing, from which he considered that 

 the remarkable disappearance of Dendroclonus 

 frontalis in 1893 was due to the severe freeze of 

 1892-93. He mentioned a stridulating sound 

 ' made by Dendroclonus terebrans by rubbing the 

 dorsal margin of the last abdominal segment 

 against the inner surface of the elytra near the 

 tips. He recorded the finding of Dendroctpnus 

 simplex breeding in the American larch in West 

 Virginia at an elevation of 2,600 feet, and con- 

 cludes that D. simplex may yet prove to be dis- 

 tinct from D. rufipennis. He further presented 

 some interesting notes on the insect enemies of 

 Scolytidse. 



This communication was discussed by Messrs. 

 Schwarz, Howard, Ashmead and Johnson. 



Mr. Ashmead stated that all of the European 

 parasites of Scolytus rugulosus have now been 

 found in the United States, the first one, Chi- 

 ropachys colon, having been recognized 20 years 

 ago by Mr. Howard. 



Mr. Johnson stated that he had studied 

 Scolytus rugulosus in the orchards of Mary- 

 land during the past few years. He found 

 that it attacked plums and peaches with great 

 virulence, but he had always noticed that the 

 trees thus attacked had always been damaged 

 in some way either by being barked in process 

 of cultivation 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. rugu- 

 losus. The trees had died from some per- 

 fectly obscure cause which neither he nor Mr. 

 "Woods, of the Division of Vegetable Pathology, 

 had been able to ascertain, and were immedi- 

 ately attacked in great numbers by the Scolytids. 



Dr. Hopkins stated that this beetle will at- 

 tack 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 perfectly healthy 

 trees. He instanced the Scolytus quadrispinosus 

 on perfectly healthy hickory trees at Detroit, 

 Mich. These were old but perfectly healthy 

 trees and they were not appreciably damaged 

 by the insect. At Mt. Airy, Ga., he had seen 

 an apparently perfectly healthy peach tree 

 suddenly attacked by this insect for feeding 

 purposes. The feeding punctures can always 

 be distinguished from 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 experi- 

 ence some injury, however obscure, preceded 

 attack by this insect. 



Mr. Ashmead spoke of and illustrated by dia- 

 grams some important structural characters in 

 the Crabronidffi. He had recently devoted 



