5S8 TRAXS. ST. LOUIS ACAD. SCIENCE. 



Diptera. — Sy7-phid>v, (29) Mesograpta polita Say; (30) M. marginata 

 Say — both f.p. 



Lepidoptera. — Rhopalocera. (31) Lycsena comyntas Godt. Pyrali- 

 ■d<M, (32) Scepsis fulvicollis Hubn. 



Birds. — TrochilidK, (33) Trochilns colubris L.. s. on four days. 



Collinsia verna Nutt.* — The plants rise from 3 to 10 inches 

 high and grow in rather large patches, so that the flowers are 

 rendered quite attractive to insects. 



The flower resembles a papilionaceous flower in a striking man- 

 ner. The two-lobed upper lip is white and rises nearly verti- 

 cally, resembling a vexillum. Below, it is provided with a palate 

 which rests upon the lower lip and forms quite a barrier against 

 unbidden guests, and also requires the visitors to depress the lower 

 lip in order to reach the sweets. The palate is provided with 

 brownish spots which form path-finders. The lower lip is 

 blue. Its lateral lobes represent the wings, and the middle lobe, 

 which is folded longitudinally, corresponds to the keel of a papi- 

 lionaceous flower. 



The four stamens arise on the upper wall of the corolla, but 

 their filaments extend across the tube, their anthers being en- 

 closed in the infolded lobe of the lower lip. The filaments with 

 the hairs upon them completely close the tube. Insects land 

 above the filaments, and can only reach the nectar by inserting 

 their proboscides between them. After a bee has forced its head 

 in under the palate, it still requires a tongue about 3 mm. long 

 to reach to the bottom of the tube. The anthers have their broad 

 faces extending vertically, and, on account of the unequal length 

 of the filaments, are arranged in an irregular row, so that the}' 

 lie as snugly as possible in the keel-like middle lobe of the 

 lower lip. 



After the lip has been depressed, it returns to its position en- 

 folding the anthers. The pollen is thus protected from Syrphi- 

 dce^ AndrenidcB and beetles, and can only be collected by bees 

 which are strong enough to depress the lip. The anthers dis- 

 charge their pollen in succession, those of the longer stamens 

 first. Accordingly, in order to collect all of the pollen, bees must 

 visit each flower several times. 



* See ^Sluller: Fertilization of Flowers, 436. 



