52 Bulletin Wisconsin Natural History Society. [Vol. 7, Nos. 1-2. 



of a large number of heads a broad flat inflorescence is formed. 

 In its upper part the floret widens out to a cup I mm. in width, 

 and of the same length with spreading lobes. The slender stylar 

 branches attain a length of 3 mm., and gradually become strongly 

 divergent so as to come in contact with the stylar branches of 

 neighboring florets, thereby giving rise to a mode of cross-pollina- 

 tion called geitonogamy. As a rule these flowers receive the at- 

 tention of a numerous set of visitors. The following 113 species 

 have been noted at the flowers : 



EUTROPOUS. 



Bees : 1, worker, s. ; 6, worker, s. and c. p. ; 7. male, s ;. 24, 

 female, s. and c. p. ; 35, female, s. and c. p. ; 38, female, s. and e. p. 



HEMITROPOUS. 



Bees: 89, male and female, s. and c. p.; 105, male, s. ; 113, female, 

 p.; 114, male, s. ; 115, male, s. ; 118, female, s. and e. p.; 119, female, s. ; 

 124, female, s. ; 128, male, s. ; 135, female, s. 



Wasps : 142 ; 147 ; 149 ; 154 ; 198 ; 201 ; 202— all s. 



Flies: 273; 274; 275; 281; 287; 306; 308; 313; 314; 315; 316; 

 319; 330; 332; 333; 335; 337 — all s. or f. p. 



Butterflies and moths: 450; 451; 458; 467; 469; 472; 477; 482; 

 487; 488 — all s. 



ALLOTEOPOUS. 



Wasps: 137; 157; 160; 162; 163; 164; 167; 169; 171; 172; 173; 

 174 ; 179 ; 180 ; 191 ; 192 ; 194 ; 205 ; 206 ; 210 ; 212 ; 216 ; 217— all s. 

 Cxiekoo-fly: 220, s. 



Parasitic* wasps: 226; 230; 233; 235; 245— all s. 

 Flies: 257; 262; 269; 347; 369; 372; 373; 374; 377; 378; 381; 

 383; 384; 389; 400; 403; 407; 408; 412; 413; 434; 438; 442; 443; 444 

 -all s. or f. p. 



Beetles: 509: 519; 522; 527; 537; 540— all s. or f. p. 

 Bug-s : 553 ; 554 ; 560— all s. 



Eutrop 6 = 5.3% 



Hemitrop 44 = 38.9% 



Allotrop 63 = 55.8% 



11. Eupatorium urticaefolium Reichard. White Snakeroot. 



This is B. arcraloidcs L. of the former edition of Gray's Man- 

 ual. Its first flowers make their appearance around August 14, 

 about 3 weeks later than those of the other 2 species, and its 

 blooming period terminates around October 6. The white florets, 

 of which 15 to 18 constitute a head are more cylindrical in their 

 upper parts than those of the preceding species, being 2 mm. long 



