OF WASHINGTON. 153 



EXPLANATION OF PLATE I. 



1. Lithobius, anterior part of body. 



2. Head of larva of Perlid. 



3. Head of adult Pcrla. 



4. Mouth parts of Perlid larva. 



5. Mouth parts of Lithobius. 



6. Mouth parts of Cermatia. 



7. Coxa of Panorpa. 



8. Mecistocephalus, anterior part of body. 

 Legend : 



//, head ; /, lip ; ///, maxillae ; /, leg I, which becomes part of 

 maxilla ; />, poison-claw ; 5, dorsal scutas ; /, spiracles ; w, 

 mandible ; x, antenna. 



Dr. Gill asked Mr. Banks whether his views as to the mouth 

 parts of insects corresponded with those of Prof. John B. Smith. 

 Mr. Banks replied that he did not believe that Prof. Smith's 

 investigations had been carried on along the same line as his 

 own. He did not believe that Prof. Smith suspected that the 

 maxilla was a compound organ. 



The subject of Myriapoda and their relation to insects and 

 other Arthropods was discussed by Messrs. Morris, Gill, Banks 

 and Ashmead. Dr. Gill said he thought Mr. Banks' theories as 

 set forth in his paper just read were plausible, although, of 

 course, it remained to be seen whether further investigation 

 would bear them out. 



Mr. Schwarz exhibited and described a structure made by a 

 Psyllid larva on the leaves or young shoots of Piscidia ery- 

 thrina, the fish-killing plant of the West Indies, at Key West, 

 Florida, and at Cayatnas, Cuba. He stated that among the 

 numerous species of North American Psyllidas there are com 

 paratively few that are gall-makers, or that cause deformations 

 in the various parts of the plant they affect. Only two nest- 

 making or nest-spinning Psyllidae have hitherto been known, 

 and these only from Australia, /. <?., the genera Spondyliaspis 

 and Cardiaspis, as explained by him in a paper read before the 

 Society some time ago.* The species from Key West forms a 



*Proc. Ent. Soc. Wash., iv, No. 2, pp. 66-73, March 21, 1898. 



