JULY, 1900. GRAENICHER— FERTILIZATION OF SYMPHORICARPOS, ETC. 145 
to come in contact with the stigma. There is a shght dilation 
of one side of the corolla tube in its lower portion, which is more 
pronounced in the bud. 
The flowers are homogamous and the introrse anthers open 
gradually, one by one. Insects insert their heads, as a rule 
between the stigma and the anthers. Visiting flower after 
flower, with the sides of their heads dusted with pollen, they nat- 
urally convey pollen to the stigmas which are on the same level 
with the anthers and usually effect cross-fertilization. Sponta- 
neous self-fertilization may take place by the falling of pollen on 
the stigmas when the flowers are horizontal or pendulous ; in 
erect flowers this can not occur. 
In the following I give a list of insects taken on the flowers 
in the summer of 1899: 
A. Hymenoptera. 
Apidae: (i) Apis melliUca, L. (2) Bomhus ainericano- 
riim, F. ^ ; (3) ^. consimilis, Cr. ? ? ; (4) B. fervidus, F. 
^ ; (5) B. pennsylvanicus, Deg. U ; (6) B. pleiiralis, Nyl. 9; 
(7) Ceratina dupla, Say. 9 ; (8) Osmia atriventris, Cr. 9 ; (9) 
Nofnada aifabilis, Cr. ? ; Andrenidae : (10) Halictus fasciatiis, 
Nyl. 9 ; (11) H. similis, Sm. 9 ; (12) Halictus sp. 9 ; (13) 
Agapostemon, radiatiis, Say. 9 ; (14) A. viridiilus, F. 9 ; (15) 
Andrena claytoniae, Rob. 9; (16) A. forhesii, Rob. 9 ; (17) 
A. rugosa, Rob. 9 ; (18) Colletes eulophi, Rob. 9 ; (19) Sphe- 
codes dichrous, Sm. 9 ; Vespidae : {2o)Vespa germanica, F.; 
(21) V. maculata, L.; (22) Polistes pallipes, Lep.; Eumenidae: 
(^23) Eumenes f rat emus, Say.; (24) Odynerus capra, Saiiss.; 
(25) O. foraminatns, Saiiss.; (26) O. leiicomelas, Sauss.; (27) 
O. tigris, Sauss.; (28) O. walshianiis, Sauss.; Crabronidae : 
(29) Crabro interruptiis, Lep.; Philanthidae : (30) Philanthus 
biliinatus, Cr.; (31) P. piinctatus, Say.; (32) Cerceris fumipen- 
nis, Say.; (33) C. nigrescevis, Sm.; Bembecidae: (34) Bembe.v 
spinolae, Lep.; Larridae : (35) Tachytes pepticiis, Say.; Sphe- 
cidae: (36) Ainmophila vulgaris, Cr.; (37) Pelopoeus cemen- 
tarius, Driiry; (38) Sphex ichneumonea, L.; (39) vS. pennsylva- 
nica, L.; Ponipilidae : (40) Pompilus tenebrosus, Cr.; Scoliidae : 
(41) Scolia eonfluenta, Say. — all s. 
B. Diptera. 
Syrphidae: (42) Syrphus americanus, Wied.; (43) Allo- 
grapta obliqua, Say.; (44) Mesogramma geminata, Say.; (45) 
M. marginata, Say.; (46) S phaerophoria cylindrica, Say.; (47) 
Eristalis bastardi, Macq.; (48) E. dimidiatus, Wied.; (49) E. 
flavipes, Walk.; (50) E. meigenii, Wied.; (51) E. transversiis. 
