OF WASHINGTON. 21 



attracted to light as not very satisfactory, and spoke of the obser 

 vations of various entomologists. Probably the most thorough 

 investigation of this subject was made on cotton-field insects by a 

 Mr. Mitchell, at Victoria, Texas. Mr. Mitchell captured 24,000 

 specimens at lights, and a determination of this material showed 

 that about 15,000 of these were made up of injurious species, the 

 remaining 8,000 being beneficial. Of these latter, there were 

 5,000 specimens of a single species of Carabid beetle. Prof. 

 Riley's experience with light in an orchard went to prove that, 

 contrary to what the manufacturer at Hazeltine claimed, the Cod 

 ling Moth was not attracted by it. Mr. Ashmead believed that 

 seventy-five per cent, of the insects attracted to lights were inju 

 rious. Mr. Sanderson and Mr. Busck considered the benefit of 

 these traps as doubtful, but Mr. Busck thought a trap could be 

 manufactured which would capture moths to the exclusion of 

 beetles; he had used such a trap. Dr. Gill mentioned having 

 observed a remarkable swarm or flight of insects to light in the 

 Island of Trinidad. This flight lasted from twilight to very early 

 morning, and was at its maximum at about 10 o'clock. Among 

 the insects flying were many winged ants. Mr. Chapin said that 

 enormous numbers of insects of all orders, and particularly may 

 flies, swarmed to the electric lights in Chicago when the arc 

 lights were first established there. In reply to a question asked 

 by Dr. Gill, Dr. Howard thought mosquitoes were not attracted 

 to lights. In conclusion, he said he thought the whole trap- 

 lantern scheme for destroying injurious insects more or less of a 

 fraud. 



The first paper of the evening was by Mr. Sanderson, and 

 was entitled : 



NOTES UPON THE STRUCTURE AND CLASSIFICATION OF 

 CHRYSOMELID LARV^. 



By E. DWIGHT SANDERSON. 



Few families of insects, and none among Coleoptera, contain 

 more injurious species or do more damage than the Chrysomelidse. 

 The rapid spread and voracious appetite of the Colorado potato 

 beetle have made it familiar to every farmer in the land, and 

 many of its near relatives are fast pushing themselves into promi 

 nence. The flea beetles, grape and corn root-worms, and the 

 cucumber and asparagus beetles, have caused the loss of millions to 



