Robertson — Flowers and Insects — Labiate. 125 
or mid-length tongues, but rather short tongues can reach the 
nectar by forcing their heads into the throat. The plant 
blooms from June 22 to Oct. 7. The visitors observed on 9 
days, between June 23 and Aug. 29, are as follows: — 
Hymenoptera—Apide: (1) Bombus americanorum F. (¢/'8, 8., freq.; (2) 
B. vagans Sm. 8, 8.; (3) Anthophora abrupta Say <',s.; (4) Melissodes 
bimaculata Lep. ¢'@, s., freq.; (5) Ceratina dupla Say 9, s., ab.; (6) Meg 
gachile brevis Say 9, s., ab.; (7) Alcidamea producta Cr.9 ,s. andc. p., 
freq., (8) Calliopsis andreniformis Sm. ,j,s. ene co (9) Agapostemon 
nigricornis F. 9, s.; (10) Halictus confusus - Pp. 
Lepidoptera Bhopalocera: (11) papers ntact F.; (12) ee 
cernes B.-L.; Noctuide: (13) Plusia simplex Gn., in the evening—al 
Sips cbsmioae (14) Systeechus vulgaris Lw., s-; ERE (18) 
Syrphus ribesii L., f. p.; (16) Mesograpta marginata Say, f. p. 
aechens: 
D e|24| 2156 
Bie<| 818 {4 
= 4 i & =I 
iB 1218 (5 
ee eB eel 
Stachys silvatica — e Germany — Miiller...|| 3} 3 |+---| 2 |----|| 8 
renees — MacLeod..... 1 1 
recta — Alps Miiiler,.<.. ++. 4 | 4 
ia Germany ‘* 2 f, 2 
nees acLeod. -...-. 1 3 
Betonica— Low Ger pone SEI pps ye B18 lessnl 21 oe Lie 
palustris— ‘* wht iy oer Bae 48 
Tllinois. eel] 2 6 2 3 3 i! 16 
Review of the Labiate. — As in the case of nototribe flow- 
ers in general, I suppose that the form from which the orig- 
inal ancestor of the Labiate was developed was a regular 
horizontal gamopetalous flower in which insects were pre- 
vented from alighting upon the stamens by a tube which 
concealed them. The insects were thus required to land upon 
the lower border and to enter the flower on the lower side, 
touching the anthers and stigma with their backs and insert- 
ing their proboscides into the lower side of the tube. Conse- 
quently, the flower has become modified to suit an insect 
entering in this way. In the typical Labiate flower we find two 
lips, an upper one forming a helm protecting the anthers and 
stigma, and a lower forming a landing-place for visiting insects, 
as well as being the principal attractive organ. Below these is 
the contracted tube serving to lodge and conceal the nectar. 
