NEW FOSSIL INSECTS FROM FLORISSANT, COLORADO. 



By T. D. a. Cockerell. 



It was not at first intended to do any work at Florissant dur- 

 ing the summer of 1909, but two of my students, Messrs. Rusk 

 and Duce, having become interested in the study of fossils, 

 arranged to go there for a short time. Their collections include 

 the usual percentage of insects, several of which are new and are 

 herewith described. 



HVAIENOPTERA. 



Eriocampoides revelatus sp. n. (Tenthredinidte ; Phyllotomin^.) 



Length about 12 mm. ; anterior wing about 8^; thorax black; legs 

 hardly visible, but apparently black; abdomen reddish -brown, very 

 robust, 4i mm. broad; wings ample, faintly dusky, anterior wings 

 with stigma and nervures brown. 



Venation not essentially different from that of Eriocampoides 

 (cf. Macgillivray, Pr. U. S. Nat. Mus., 1906, pi. XXX, figs. 52 and 53); 

 the most striking peculiarity is in the hind wings, in which the vein 

 which should form the truncate apex of the radio-medial cell (marked 

 M in Macgillivray's figures) is wanting, the discal cell being actually 

 joined to (contiguous with) the radial for a very short distance, and 

 the end of the radiomedial cell consequently pointed. In other 

 respects, as the form of the lanceolate, cubital and discal cells, the 

 hind wing agrees with that of E. CBthiops. The peculiarity referred 

 to may be a variable one, as on one side the medio-cubital vein is 

 broken and a little displaced, but looks as if it had been so attached as 

 to leave an extremely short interval between the discal and radio- 

 medial cells; in this case the description should read, discal cell touch- 

 ing or almost touching the radial, which would afford a very good 

 distinction from the living species. The upper side of the discal cell 

 is about 629 /« long. 



The following measurements of the anterior wings arc in microns: 



Cross-nervure of marginal cell, which is long and curved but not 

 bent, about 1105. 



First submarginal cell on first discoidal 527. 



Second submarginal cell on marginal 1020, on first discoidal 510, 

 on third discoidal 884. 



Third submarginal cell on third discoidal 340. 



Second transverso-cubital nervure to insertion of marginal cross- 

 nervure 1020; the latter to third transverse-cubital 306, and to apex 

 of marginal cell 1496. 



Basal side of first discoidal cell (basal nervure) 1275, its apical 

 side 765. 



Lower end of basal nervure to transverso-medial 680, length of 

 the latter 697. 



Second discoidal cell on first 782. 



Beginning of cross-nervure of lanceolate cell to lower end of trans- 

 verso-medial 1054. 



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