20 



to their details is too limited to admit our using them to a profitable extent. We begin 

 to be better acquainted with the previous stages, and this acquaintance will bring these 

 characters into more prominence. I doubt embryological characters to be of generic value. 

 But very little is certainly known about them, and nothing known is ready for our use. 

 The parts serving for propagation have probably a higher value than generic characters. 

 Characters for genera should be of a co-ordinate value. I think it is obvious that a genus 

 should never be accepted if its characters are not satisfactorily given, and that genera 

 based on the mere specification of a type should never be accepted. 



INSECTS INTRODUCED BY THE CENTENNIAL EXHIBITION. 



During the progress of the Centennial Exhibition, it was observed that many of the 

 cereals and seeds exhibited were infested with insects, some samples being almost de- 

 stroyed by these pests. At the suggestion of the Centennial Commission, a com- 

 mittee of scientific gentlemen was appointed to investigate this matter and report as early 

 as practicable on the character of the insects thus introduued. This committee was also 

 charged with the further work of reporting on any new plants or weeds which might 

 be similarly brought into the country. A report on the plants could not be prepared 

 until next year, but as the subject of injurious insects was a highly important one, it was 

 deemed wise to report on that as soon as possible, hence all the information obtainable on 

 the subject up to the time of the close of the Exhibition was submitted in the following 

 report, read by Dr. LeConte, chairman of the committee, at a meeting of the Academy 

 of Natural Sciences in Philadelphia, held early in November : — 



REPORT ON INSECTS INTRODUCED BY MEAN.S OF THE INTERNATIONAL EXHIBmON. 



On behalf of the Committee appointed by the Academy of Natural Sciences of Phi- 

 ladelphia, at the meeting held October 10th, 1876, " to investigate and report upon 

 the introduction of new species of insects and plants through the medium of foreign ex- 

 hibits at the Centennial Exhibition," I have the honour to present the following report, 

 with the desire that it may be forwarded to the proper authorities of the Centennial Com- 

 mission, at whose instance the Committee was appointed. 



The Committee is composed of the following members of the Academy : — 



Dr. Joseph Leidy, Dr. George H. Horn, Mr. Thomas Meehan, Dr. J. Gibbons Hunt, 

 and Dr. John L. Le Conte, Chairman. 



It was apparent that while the labours of the botanists of the Committee could not 

 properly commence until next spring, when careful observation will recognise any new 

 introductions of plants, the entomological investigations should be made as speedily as 

 possible. Accordingly, Dr. Horn and myself, availing ourselves of the admission cards 

 which had, with great liberality, been sent to the members of the Committee, went fre- 

 <iuently to the exhibits in the Main Building and Agricultural Hall, and made col- 

 lections in all the agricultural products from foreign countries, which were found to be 

 infected. 



Most of the species which we obtained have been already distributed over the globe 

 by the ordinary channels of trade, and nothing is to be apprehended from the addition of 

 a few hundred thousand specimens, to the incalculable millions of individuals of the same 

 kind, that we have now domiciled amongst us. 



I am happy to add that the species found, which have not been previously observed 

 in the United States, will be innocuous ; they are dependant for their support upon plants 

 which do not grow here, and which would be of no commercial value to us if they were 

 •ultivated. 



