1889. J BOTANICAL GAZETTE. 3OI 



tact with them and only visits flowers in the male stage. 

 Andrenida : (7) Augochlora fura Say 9 , c. p., works out 

 the pollen with her jaws and front feet, not touching stigma ; 

 (8) Halictus confusus Sm. 9 , c. p., like no. 6. 



Lepidoptera — Rhopaloccra: (9) Papilio troilus L. s. 



Coleoptera — Chrysomelidce: (10) Diabrotica 12-funciata 

 F., gnaws holes in spurred sepal. 



Nos. 1-5 and 8 are useiul visitors, while the rest are not. 

 Differences in the pollen-collecting habits of Bombus and 

 Megachile are well illustrated in this case. The former re- 

 ceives pollen on the dorsal surface of her thorax and wipe it 

 off with her front legs to place it in her baskets, the latter 

 turns so as to receive it directly in her scopa. Small specks 

 of Halictus commonlv visit flowers adapted to larger insect 

 to collect pollen directly from the anthers or to glean stray 

 grains which are scattered about the flower. In the latter 

 case they do no harm. The Syrphidae also often act as glean- 

 ers of stray pollen, and only do harm when they eat it di- 

 rectly from" the anthers. 



P~oIlen-cratherino- is illegitimate behavior in this flower. 



since it leads the bees to pav more attention to the flowers 

 which are in the male stage. When 2 and 3 are after pollen 

 thev neglect flowei s in the second stage, since they instantly 

 perceive that the anthers have fallen. The humming-bird 

 coming onlv for nectar, and being the most rapid flier, is bv 

 far the most useful visitor, and it is but natural that it should 

 have most influence in modifying the flower. 



Impatient pallida Nutt.— The flower is •• pale-yellow, spar- 

 ingly dotted with brownish red." It is much lar-er than in 

 I. fulva, and has a shorter (13 mm.) and broader posterior se- 

 pal and a large horizontal landing— characters which tavor 

 humble-bees. The incurved spur measures about o mm. 

 Humble-bees are more abundant and more constant in then 

 visits than in I. fulva, while humming-birds were not seen 



visiting the flower. _ . . . • 



Visitors: Hvmenoptera-^/V/*.- (0 Bombm vrgmtcus 

 OHv. * , s . and c. p., ab. ; (2) B. amcricanorum F * , s. ab. : 



(3) Megachile b reins Sav 9 , c. p., behaves as with I. falva 



Audrenidce: (4) Halictus sp., s., not touching anthers and 



sti gmas. „ AC „ 



Diptera — Syrfhidm: (5) 



""dilation or perforation of the flowers of this species » » recorded b> Bailey ! Tor- 

 rey Bull. vi. \i:v. Trelea.se: Ibid rIL »; Van Ingen : But. Gaz. mi. at. 



