OF WASHINGTON. 63 



Mr. Kraus said that he had marked one female wasp (Try- 

 poxylon albitarsis Fab.) with whiting and that she built five 

 tubes side by side. Mr. Schwarz said that in the case he ob- 

 served, two tubes were built by two wasps working together. 



The following papers were presented for publication: 



ON TWO NEW SPECIES OF PARASITES OF 

 ALEYRODID^. 



By L. O. HOWARD. 



In the course of the extensive investigations of the white 

 fly (Aleyrodes citri R. & H.) now going on in Florida under 

 the auspices of the Bureau of Entomology, as described by 

 Mr. Marlatt at a recent meeting of the Society , a much atten- 

 tion is being paid to parasites. A. citri is as yet unparasitized, 

 but other Aleyrodidae are frequently killed in great numbers 

 by several species of parasites of different genera. An effort 

 is being made to induce the parasites of other species to 

 attack A. citri, and as many species as possible are being 

 introduced into Florida with this end in view. As yet none 

 of them has attacked A. citri. A recent series of slides re- 

 ceived from Dr. A. W. Morrill contain, among others, two 

 new species which are here described. 



Subfamily APHELININ^: Howard. 



Genus ENCARSIA Foerster. 



Encarsia Foerster, Kleine Monographien, 1878, pp. 65-66. (Type, 

 Encarsia tricolor Foerster). 



Including the single species here described, 14 species of 

 this genus have been recognized, of which one was described 

 by Foerster, one by Zehntner, and the remainder by the writer. 

 Like other parasites of Coccidae and Aleyrodidae, the genus is 

 now of wide distribution and if it were ever once localized it 

 is now too late to approximate its original range. It is now 

 represented in Europe, North America, Java, South Africa, 

 West Indies, and Mexico. 



Twelve of the 14 species have been reared, and of these 12, 

 3 have come from diaspine scale-insects and the remaining 9 

 from Aleyrodidae. From the rearings so far made, the species 



'See Proc. Ent. Soc. Wash., ix, pp. 121-124, 1908. 



