Robertson — Flowers and Insects ~ Labiate. 105 
flowers has little importance, except as a record of a former 
condition. The flowers are erect or nearly so, and the lips 
are so widely expanded that the stamens are fully exposed and 
the tubes are about equally accessible from any side. Then 
the flat-topped inflorescence forms a most convenient resting- 
place for insects which would find great difficulty in visiting 
the flowers if they were widely separated. 
From his observations on the American P. lanceolatum and 
prlosum in the Berlin garden, Dr. E. Low * arrives at the 
erroneous conclusion that they are specially adapted to diptera. 
He found a plant with female flowers, from which it appears 
that the genus has gynodicecious species. Later, Meehan 
records f the occurrence of gynodiecism in P. muticum. 
The tubular portion of the corolla is about 5mm. long, and 
nectar rises in the tube so as to become accessible to tongues 
which cannot drain it. It blooms from July 14 to Sept. 7. 
July 31, the following list was observed, all the insects 
sucking : — 
Hymenoptera — Apide: (1) Apis mellifica L. 8, ab.; (2) Heriades cari- 
neatum Cr. 9; (3) Celioxys 8-dentata Say 9; (4) Epeolus remigatus F.; 
(5) E. lunatus eed @, freq.; (6) Calliopsis andreniformis Sm. ¢'9; Andre- 
nide: (7) Nomia nortoni Cr. ¢'; (8) Agapostemon radiatus Say J’, ab.; 
(9) Augochlora lucidula Sm. 49; (10) Halictus pectoralis Sm. 9; (11) 
H. similis Sm. ¢/; (12) H. parallelus Say 9; (18) H. lerouxii Lep. f'9, 
(14) H. gece Say 9; (15) H. faciatus Nyl, ¢'9, ab.; (16) H. confusus 
Sm. 9, ab.; (17) H. stultus Cr. og’, freq.; (18) Sphecodes arvensis 
Pitn. dP, ee  Bukentter (19) Zethus spinipes Say; (20) Odynerus dorsa - 
lis F.; (21) 0. arveriets Sauss. ; (22) O. foraminatus Sauss.; Crabronide: (23 
Oxybelus emarginatus Say; Philanthidee: (24) Eucerceris zonatus Say, 
freq.; (25) Cerceris fumipennis Say; Sphecide: (26) Ammophila procera 
Klug, ab.; (27) A. vulgaris Cr.; (28) A. pictipennis Walsh; (29) A. gra- 
cilis Lep.; (30) A. intercepta Lep.; Scoliide: (31) Myzine 6-cincta F.; “32) 
M. interrupta Say; (33) Scolia bicincta F. 
Diptera — Bombylide: (34) Exoprosopa fasciata Mcq ; (35) E. fascipen- 
nis Say; Conopide: (36) Zodion fulvifrons Say; (37) Oncomyia loraria Lw. ; 
Syrphide: (38) Spherophoria cylindrica Say; (39) Eristalis tenax L.; (40) 
Syritta pipiens L.; Tachinide: (41) Hyalomyia robertsonii Twns.; (42) 
Trichopoda pennipes F.; (43) Cistogaster occidua WIk.; (44) Jurinia apici- 
fera WIk., ab.; (45) Acroglossa hesperidaram Will., freq.; Muscide: (46) 
Compsomyia macellaria F., freq. 
* Beitriige z. Kentniss d. Bestiiubungseinrichtungen einiger Labiaten, 
+ Proc. Acad. Nat. Sci. Phil., 1890. 
