COCKERELL: FOSSIL HYMENOPTERA FROM FLORISSANT. 37 



The following abbreviations are used : b. n. = basal nervure; s. m. = submarginal 

 cell; r. n. = recurrent nervure ; t. m. = transverso-medial nervure ; t. c. = trans- 

 verso-cubital nervure. In the wing, breadth always means in the direction of 

 the short axis in the case of the marginal cell and stigma. 



CERATINIDAE. 



Ceratina disrupta, sp. nov. 



Black ; probable length about 8 mm., or perhaps less ; anterior wing about or 

 not quite 6 mm., dusky, especially in marginal cell and beyond ; head separated 

 a short distance from body in type and seen in side view, about 2175 /u. long and 

 1050 from back to front, with the broadly rounded cheeks and general appear- 

 ance of Ceratina ; stigma well-developed, its width about 150 (this and all follow- 

 ing measurements in /*), its margin bordering marginal cell about 300; marginal 

 cell 1350 long, 370 wide, ending in a point a little away from costa; first s. m. 800 

 long, its length on cubital nervure 525 ; second s. m. much narrowed above its 

 length on marginal 200, on cubital nervure 600 ; third s. m. 300 long on marginal, 

 nearly 600 on cubital ; lower section of b. n. (bordering first discoidal) gently, not 

 strongly, curved, about 675 long; length of first discoidal 1500; first r. n. entering 

 second s. m. beyond middle ; second r. n. entering third s. m. 150 from its end, the 

 upper end of the nervure not bent. 



Type.— No. 2001, Mus. Comp. Zool. Florissant, Col. (No. 9355, S. H. 

 Scudder Coll.). 



MEGACHILIDAE. 



Anthidium Fabricius. 



The species of Anthidium differ among themselves in the details of the 

 venation, as shown in the following table : 



First r. n. meeting first t. c, or passing a very short distance beyond it. 



A. oblongatum Latr. (Europe). 

 A. hernardinum Ckll. (So. Calif.). 

 A. illustre Cress. (Western U. S.). 

 First r. n. passing a fair or long distance beyond first t. c 1 



1. B. n. meeting t. m. ; t. m. of hind wing only moderately oblique 



A. steloides Spin. (Chile). 



B. n. passing basad of t. m. (sometimes very slightly) ; t. m. of hind wing 



very oblique 2 



2. Basal angle of first s. m. about as acute as angle formed by basal and sub- 



costal nervures A. later ale Latr. (Palaearctic). 



Basal angle of first s. m. obviously more obtuse than angle formed by basal 

 and subcostal nervures . . . . A. emarginatum Say (Colorado, etc.). 



A. conspicuum Cress. (Colorado, etc.). 



A. scudderi, sp. nov. (Florissant). 



A. exhumatum, sp. nov. (Florissant). 



