ON THE BOTHRIOTHORACmE INSECTS OF THE UNITED 



STATES. 



By L. O. HowABD, 



Entomol-ygist, U. S. Department of Agriculture. 



No PUBLISHED attempt has been made to divide tlie large and 

 important chalcidid subfamily Eucyrtin;e into tribal groups beyond 

 the suggestion of the writer* of the use of the name Tetracnemini for 

 the Encyrtinfe possessing branched antennie. There are, however, sev- 

 eral natural divisions of the subfamily to which tribal names should be 

 given in any revision of the group. One of these is the group under 

 consideration. The extraordinary sculpture of the head caused the 

 partial association of Bothriothorax and Pluvnodiscus in the synoptical 

 tables of Foerster, Thomson, and Mayr, and to these two genera are to 

 be added two others, Chalcaspis and Petitelicus, based upon uudescribed 

 material in the U. S. National Museum. 



We unfortunately know nothing of the habits of the new genera, 

 since the few specimens known have all been collected by sweeping. 

 Of Bothriothorax, however, the habits are well known, and the species 

 are parasitic upon dipterous larva*, as follows: 



B. clavicornis, Dalmau, from Si/rphiis sp. and Anthomyia ceparum; 

 B. peculiar is, Howard, from Syrphid larva on oak; B. cali/ornicus, new 

 species, from larva of Cataeomba pyrastri, Linnteus, feeding on rose 

 aphis; B. noveboracensis, new species, from Syrphid larvre preying upon 

 hop aphis. 



We have as yet no American si^ecies of Pluvnodiscm^; but P. cer- 

 copiformis and P. aeneus of Europe, are said to be parasitic upon 

 Coccida^. 



BOTHEIOTHORACINI, new tribe. 

 Short, stout-bodied Encyrtin;ie, with very large, thimble-like puucta- 

 tion to the very broad and very short head; short, stout legs, with 

 live-jointed tarsi t and broad wings; antenna* inserted below the mid- 

 dle of face, eleven-jointed, funicle joints short, scape slender, or with 

 leaf-like expansion. 



* Proc. U. S. Nat. Mas., xv, 1892, p. 361. 



t This seemingly unnecessary statement oftLe number of the tarsal joints is ren- 

 dered necessary by the discovery by Aurivillius of a true Eucyrtine with four-jointed 

 tarsi {Arrhenophafjus) . 



Proceedings of the U. S. Xatioual Museum, Vol. XVII— No. 1025. 



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