No. 10. New Phytophagous Hymenoptera from the Tertiary 

 of Florissant, Colorado. By CHARLES T. BRUES. 



OVER a year ago I received from the Museum of Comparative Zoology 

 the large collection of undetermined fossil phytophagous and parasitic 

 Hymenoptera collected many years ago by Dr. S. H. Scudder in the 

 Tertiary lake basin at Florissant, Colorado. Since then a large number 

 of additional parasitica have been received from the same locality from 

 Prof. T. D. A. Cockerell, who has been collecting there for the past two 

 summers. 



The present paper contains a consideration of the phytophagous forms 

 belonging to the Tenthredinidae, Lydidae, and Siricidae. These are very 

 much less numerous than the parasitic ones. 



Three genera and twelve species are described as new, and reference 

 has been made to the more definite records of occurrence of members 

 of the group in the various Tertiary formations of Europe and North 

 America, the only continents where they have been discovered. 



A catalogue of the recorded species and genera is also included. 



The figures are reproduced from drawings made with the aid of a 

 camera lucida. 



TENTHREDINIDAE . 

 Trichiosomites, gen. nov. 



Radial cell of front wings long, not appendiculate ; divided at its basal third 

 by a transverse nervure. Submedian cell only a little longer 'than the median. 

 Anal cell divided into cells connected by a petiole, much as in Pachyprotasis or 

 Hemichroa. Basal vein and first recurrent nervure almost parallel, the second 

 transverse cubitus and the second recurrent nervure interstitial. 



The long marginal cell and interstitial second recurrent nervure remind one of 

 Trichiosoma, as does also the oval abdomen. There are such important differences, 

 however, that I feel compelled to erect a new genus for the reception of the 

 single species, which I cannot place in any described genus. The long marginal 

 cell is similar to that of Paremphytus. 1 



1 Since this paper went to press Mr. S. A. Rohwer of the University of Colorado 

 writes me that he has identified the same species in material from Florissant, which 

 shows that the genus is closely related to Zarea Leach. The antennae are six- 

 jointed. 



