10 ]\Ir. T. D. A. Cockoiell — Descriptions and 



narrow elevated median line ; facial fovese very pale oclirey, 

 rather narrow, separated from eye by a shining line, and 

 going a little below level of antenupe ; third antenna! joint 

 longer than the next two t()<iether, but not so long as the 

 next three; mesotliorax dullish, somewhat shining, with 

 rather close punctures, weaker and smaller than those on 

 clypeus ; area of metathorax triangular, with no elevated 

 rim, more than its basal half quite coarsely roughened ; 

 tegulse rufo-piceous. ^Vings dusky reddish, but not very 

 dark ; stigma and nervures light ferruginous ; b. u. falling 

 some distance short of t.-m. ; second s.m. ordinary, receiving 

 first r. n. in middle. Scopa of hind tibitC pale ochreous, 

 rather short and stiff" ; spurs pale ferruginous. Abdomen 

 shining, finely but not very densely punctured, the first 

 segment with scattered very minute punctures ; second 

 segment depressed k'ss than half, but rather over a third. 



Hub. Boulder, Colorado, at flowers of Lejndiwn medium, 

 Greene, May 26, 1913 {M. D. Ellis). 



In various tables this runs rather persistently to the 

 vicinity oi A. arabis, Rob., but that is only 10 mm. long and 

 has a fuscous fimbria. In Viereck's Connecticut table it 

 appears to run to A. hilaris, Sm., which is considerably 

 larger and more robust, with darker wings, and the eyes 

 converging above. 



In the following key I record other species of Andrena (?) 

 taken by Mrs. Ellis at Boulder, and contrast them with 

 A. ellisia : — 



Hair at apex of abdomen black or nearly 1 . 



Hair at apex of abdomen pale or reddish or greyish. 2. 



1. Abdomen blue-black, very shiny (May 23-24, fls. 



HiidropJujllinn fendlerl) geranii, Rob. 



Abdomen satiny green or blue (April 26, fis. Saliv ; 



May 11, Hs. Taraxacum taraxacum) Candida, Sm. 



2. Tarsi clear red; Hagellam red beneath (May II, 



fls. Salix and Taraxacum taraxacum ; 31ay 18, 



fls. Mkus trilobata) salicinella, Ckll. 



Basitarsi dark 3. 



3. Ilagellum bright red at apex ; abdomen strongly 



pimctured ; palpi very long and slender (May [Rub. 



22, tis. ] io/a nuttallii) {lomelissa) viulcs, 



Flagellum not bright red at apex 4. 



4. Abdomen greenish ; thorax with dull purplish tints 



above ; stigma amber (April ■2('), 23 at tis. Salix). illinoensis, Rob. 

 Otherwise, but all with amber stigma 5. 



5. Abdomen, including first segment, very strongly 



punctured (April 28, lis. I'araxactivi taraxacum) bridicelli, Ckll. 

 First abdominal segment feebly or not clearly punc- 

 tured 6. 



