Robertson — Flowers and Insects. 461 
ERIGERON PHILADELPHICUS L.— The stems grow a few deci- 
metres high and expose several heads which expand about two 
centimetres. The ray florets are pistillate, are very numer- 
ous and slender and white, or purplish tinted. The disc 
florets are yellow. The tubes are very narrow and measure 
about four millimetres in length. The nectar is easily 
obtained by small, long-tongued insects which find a conve- 
nient resting-place upon the disc. Pollen is forced out of the 
anther tube in the usual way. 
The flower blooms from April 26 to June 13. On May 24 
and 28 and June 2 and 5, the following list was observed : — 
Hymenoptera — Apidae: (1) Apis mellifica L. 8, s., one; (2) Ceratina 
tejonensis Cr. ', s., freq.; (3) C. dupla Say fQ, 8. and c.p., ab.; (4) 
Alcidamea producta Cr. 6, 8.; (5) Heriades carinatum Cr. <j’, s.; (6) Stelis 
lateralis Cr. 3'e, s., freq.; (7) Nomada annulata Sm. 9, 8., ab.; Andren- 
idae: (8) Halictus pectoralis Sm. 9, 8.; (9) H. coriaceus Sm. 9, 8. and c- 
P.; (10) H. ligatus Say 9, s. and c. p., ab.; (11) H. fasciatus Nyl. 9, s. and 
¢. p., freq.; (12) H. pilosus Sm. 9, s. and c. p.; (13) H. confusus Sm. 9, 
8. and c. p., freq.; (14) H. albipennis Rob. 2, s.; (15) Augochlora pura Say 
?+8.; (16) A. similis Rob. Q, s. andc.p.; (17) Sphecodes mandibularis Cr- 
Ps 8.5 (18) Prosopis pygmaea Cr. ', 8.; Eumenidae: (19 and 20) Odynerus 
Spp., freq.; (21) O.foraminatus Sauss.; (22) O.anormis Say, ab.; Sphecidae: 
(23) Ammophila vulgaris Cr.—all s. 
Diptera — Conopidae: (24) Zodion fulvifrons Say, s., freq. ; (26) Oncomi- 
yia loraria Lw., s.; Syrphidae: (26) Paragus bicolor F.; (27) P. tibialis Fil. ; 
(28) Mesograpta marginata Say; (29) Sphaerophoria cylindrica Say; Tach- 
inidae: (30) Sp.; (31) Hyalomyia purpurascens Twns.; (32) Cistogaster 
ccidua Wik., ab.; (33) C. immaculata Mcq.; (34) Siphophyto sp.: (35) 
Leucostoma atra Twns.; Sarcophagidae: (36-88) Sarcophaga spp.; Aus- 
gg (39) Lucilia cornicina F.; Anthomyidae: (40) Anthomyia albicincta 
1.; (41) Chortophila sp. —all s. or f. p. 
Colsonters— Lampyridce: (42) Telephorus flavipes Lec.; Scarabaeidae: 
vn Trichius piger F., ab.; Chrysomelidae: (44) Diabrotica 12-punctata Oliv. 
f. p. 
Lepidoptera — Rhopalocera: (45) Phyciodes tharos Dru.; (46) aes 
anus thoe B.—L.; (47) Ancyloxypha numitor F.; (48) Pamphila peckius Kby. ; 
(49) P. cernes B.—L.; Heterocera: (80) Scepsis fulvicollis Hbn.—all s. 
Hemiptera — Capsidae: (51) Calocoris rapidus Say; (52) Lygus pratensis 
L.; Berytidae: (58) Corizus lateralis Say — all s. 
ERIGERon strigosus Muhl.—This plant resembles B . phil- 
adelphicus, but is taller, blossoms later, and has white rays 
Which are less numerous and broader. The corolla tubes are 
shorter, about two millimetres in length. 
