468 Trans. Acad. Sci. of St. Louis. 
four or five centimetres. The tubes of the disc-florets are 
very narrow and measure about three millimetres in length. 
This species blooms from July 23 to October 16. The 
following list, which contains an interesting assemblage of 
long-tongued flies, was observed on eight days, between 
August 4 and September 14 :-— 
Hymenoptera — Apidae: (1) Bombus separatus Cr. <j’, s., one; (2) Melis- 
sodes obliqua Say 9, s. andc. p.; (3) M. perplexa Cr. 9,s. and c. p.; (4) M. 
confusa Cr. ¢',s.; (5) Epeolus mercatus F. §'Q,s.; (6) Calliopsis illinoensis 
Cr. f 2,8. and c. p., ab.; (7) C. labrosus Rob. (MS) ¢'9,s. and c. p.; (8) 
C, compositarum Rob. ,j, s.; (9) C. asteris Rob. (MS) Q, s. and c. p.; 
Andrenidae: (10) Andrena aliciae Rob. (9, s. and ec. p., freq.; (11) Halictus 
pectoralis Sm. 9, s. and c. p., freq.; (12) H. coriaceus Sm. 9, 8.; (13) H. 
ligatus Say 9,s.; (14) H. fasciatus Nyl. 9, 8.; (15) Colletes compacta Cr. 2, 
8S. and c. p.; (16) C. americana Cr. 9, s. andc.p.; Vespidae: (17) Polistes 
pallipes Lep., s.; Eumenidae: (18) Odynerus arvensis Sauss., s.; Sphecidae: 
(19) Ammophila gracilis Lep., s.; Scoliidae: (20) Scolia bicincta F., s.; 
Ichneumonidae: (21) Exetastes suaveolens Walsh, s. 
Diptera — Empidae: (22) Empis sp.; Syrphidae: (23) Eristalis trans- 
versus Wd.; Bombylidae: (24) Exoprosopa decora Lw.; (25) E, fascipennis 
Say; (26) Anthrax halcyon Say, freq.; (27) Sparnopolius fulvus Wd.; (28 
Systropus macer F.; (29) Toxophora amphitea W1lk.; (30) Lepidophora 
aegeriiformis Westwood; Tachinidae: (31) Cuphocera ruficauda v. d. W.; 
(32) Epigrimyia polita Twns.; (33) Coronimyia geniculata Twns., ab.; 
he Siphoplagia anomala Twns.; Dexidae: (35) sp.; (36) Prosena sp., 
req. —all s. 
Lepidoptera — Nymphalidae: (37) Phyciodes tharos Dros ; (38) P. 
nycteis D.—H.; Papilionidae: (39) Pieris protodice B.—L.; (40) Colias 
philodice Gdt.— all s. 
Coleoptera — Mordellidae : (41) Mordellistena sp. 
LepacHys Prinnata Torr. and Gray.—The plant grows 
about one metre high. The stem and branches bear single 
heads with conspicuous, drooping yellow rays. The 
ray-florets are neutral. The disc is oblong. The tubes 
of the disc-florets are two millimetres in length. The florets 
and the chaff, with its thickened tips, form a very compact 
mass which renders it easy for Melissodes obliqua to run 
around the heads and clean up the pollen in her copious scopae- 
This bee, though by no means the exclusive visitor, is by far 
the most abundant, being more common on this than any 
other flower. This Melissodes is the most importent pollinator 
of Lepachys pinnata, and the plant in turn is the most impor- 
tant in the economy of the bee, being its chief source of 
pollen supply. 
