COCKERELL: FOSSIL HYMENOPTERA FROM FLORISSANT. 39 



as in A. scudderi (its breadth about 570 /j.) ; stigma shorter and smaller, more like that 

 of Megachile ; second discoidal cell with the upper and lower sides about equal, the 

 upper apical corner hardly depressed ; b. n. almost meeting t. m. ; first r. n. passing 

 some distance beyond first t. c. ; second perhaps passing slightly beyond apex of 

 second s. m.; second (morphologically third) t. c. strongly bent near the middle; 

 t. m. of hind wing hard to see but oblique. 



Type. —No. 2003, Mus. Comp. Zool. Florissant, Col. (No. 13,709, S. H. 

 Scudder Coll.) and reverse of the same specimen (No. 11,388, S. H. Scudder 

 Coll.). 



This is not quite so typical an Anthidium as A. scudderi, but I think it can- 

 not be referred to any other genus. These bees are referred to Anthidium and 

 not to Megachile, not only because of the color of the abdomen, but also on 

 account of the characters of the venation. The following comparison shows 

 the difference in venation between A. scudderi and Megachile calogaster : 



A. SCUDDERI. M. CALOGASTER. 



B. n. goes a little basad of t. m. B. n. falls a little short of t. m. 



First r. n. joins second s. m. at a First r. n. joins second s. m. at a 



distance from its base almost as great distance from its base not greater than 



as half length of r. n. one quarter length of r. n. 



Stigma larger and more pointed. Stigma small and truncate. 



Marginal cell conspicuously broader Marginal cell conspicuously narrower 



than greatest breadth of first s. m. than greatest breadth of first s. m. 



First discoidal much broader. First discoidal long and narrow. 



Second r. n. not well seen, but en- Second r. n. enters second s. m. 



ters second s. m. at or very near tip. about as far from apex as first r. n. does 



T. m. of hind wing very oblique. from base. 



T. m. of hind wing not or hardly 

 oblique. 



Specimen No. 8444 is an Anthidium exactly agreeing with A. exhumatum in 

 the width of the marginal cell and in the shape of the second discoidal, but 

 having most of the venation obliterated. It differs by the strongly banded 

 abdomen (suggestive of the living A. occidentale), which, however, is not 

 spotted. It appears to be a female, and I little doubt that it represents that 

 sex of A . exhumatum. 



Dianthidium tertiarium, sp. nov. 



cf Body black or dark brown, without visible markings ; head lacking ; length, 

 exclusive of head, about 8 mm. ; width of thorax about 4|, of abdomen about 4| 

 mm.; anterior wing about 9 mm. long, slightly dusky, with the nervures dark ; 

 abdomen subglobose, terminating in two rather small and obscure tubercles, which 

 are about as far distant as the breadth of the basal joint of hind tarsus at apex; 

 posterior claws with a strong inner tooth. Venation of anterior wings normal ; 

 first r. n. ending about 300 fx from base of second s. m. ; second r. n. passing about 



