450 TKANS. ST. LOUIS ACAD. SCIENCE. 



I withhold for the present the lists of visitors in order to com- 

 plete the determination of certain groups, and to raise the num- 

 ber in certain lists, so that the comparisons can he more satisfac- 

 torily made. The tables give the number of species of the several 

 groups. Unless otherw^ise stated, the observations were made 

 near Carlinville, Ills. 



Erigenia biilbosa, Nutt. — On the first warm days of spring this plant 

 raises its small white umbels just above the leaves. The plants often 

 form rather large patches, so that they are very attractive to insects, fur- 

 nishing both honey and pollen in great abundance. All of the flowers 

 are hermaphrodite, and, from a careful examination, I am satisfied that 

 Foerste* is correct in regarding them as proterogynous. 



The petals are longer than in most umbellifers and are not so widely 

 expanded, so that the disc is not so freely exposed as in many of the fol- 

 lowing species. In the female stage especially, the petals are more erect, 

 and the incurved stamens aid in concealing the nectar. 



A flower blooming so early as Erigenia does, cannot be sure to find a 

 set of flower-loving insects waiting for it, for anthophilous insects cannot 

 afford to appear until they are sure of a floral diet. But any weather 

 warm enough to bring out Erigenia flowers is certain to bring out a set of 

 insects which are able to do good work until the flower-insects come. 

 The first day I found Erigenia in bloom in 1889 was on March 21st, when 

 I noted as visitors Apis mellifica, Gonia frontosa, Lucilia cornicina, Sca- 

 tophaga squalida, and a Sarcophagid. With the exception perhaps of 

 Gonia, all of these insects may be observed on any warm day during the 

 winter. The hive-bee is introduced and so must always be regarded as 

 an intruder on native flowers. None of the other insects depend upon a 

 floral diet. We see, therefore, that Erigenia is sure of the visits of flesh- 

 flies and dung-flies at any time it may appear. It would be eftectually 

 cross-fertilizad if it depended upon Lucilia cornicina alone. The plant 

 has an advantage over Dicentra Cucullaria,f which has to wait for long- 

 tongued bees. On March 23d I found among the visitors x\ndrena hir- 

 ticeps (5" and Brachypalpus frontosus — the first of the native flower-in- 

 sects. On the 26th I found 7 Andrenidse and 2 Syrphidse, so that this was 

 the first day when the set of visitors showed an anthophilous character. 



As a result of early blooming, however, Erigenia is so far from sufter- 

 ing in the character of its visitors that it is the highest specialized of the 

 family, for it shows the largest proportion of bees. Of 62 species of insects 

 captured on the flowers, 28 are hymenoptera, and ail of these are bees 

 except a single Chrysid. During the time when this plant is in bloom I 

 have observed no other hymenoptera flying except Tenthredinid?e and Pa- 

 rasitica; these appear to be rare. The preponderance of bees, therefore, 



* Bot. Gazette, vii., 70. f Bot. Gazette, xiv., 125. 



