584 ANGIOSPERMAE—DICOTYLEDONES 



barrier. This is of some significance in connexion with polhnation, since the ants 

 would frighten away pollinating insects, while the aphides with their sweet excretion 

 help to attract them, and thus play the part of ' living nectaries.' 



1330. A. salicifolius Scholl. (=A. salignus Willd., and A. pamculatus Lam.). 

 (Knuth, ' Blutenbiol. Herbstbeob.') — The tall much-branched stem beaiing numerous 

 heads serves to render the plants of this species conspicuous from a distance, 

 attracting a larger number of species of insects than in almost any other autumnal 

 form. Each head contains 20-30 ray-florets ( 1 5 mm. long) with blue corolla-lobes 

 (10 mm. long and 2 mm. broad), and 30-40 yellow disk-florets 9 mm. in length, 

 of which the ovary takes up 2 mm., the contracted part of the corolla-tube 4 mm., 

 the nectar-containing bell 2 mm. (this is -^ mm. in diameter), and the corolla-lobes 

 I mm. The flower mechanism agrees completely with those of Aster Tripolium Z. 

 and A. Amellus Z., except that the diameter of the bell is larger, and the nectar 

 is therefore readily accessible even to insects with a stout proboscis or thick tongue. 

 Ludwig states that the disk-florets of the older heads assume a bright red colour, as 

 do those of A. parviflorus Nees (Justs bot. Jahresber., Leipzig, xiv, (1886) 1888, p. 806). 



Visitors. — I observed the following. — 



A. Diptera. {a) Muscidae: all skg. : i. Anthomyia sp. ; 2. Calliphora vomi- 

 toria L.; 3. Lucilia caesar Z. ; 4. L. cornicina F.; 5. Pollenia vespillo F.; 6. Sepsis 

 cynipsea Z. (b) Syrphidae: all skg. and po-dvg. : 7. Eristalis arbustorum Z. ; 8. E. 

 nemomm Z. ; 9. Helophilus floreus Z. ; 10. H. pendulus Z. ; 11. Melanostoma 

 gracihs Mg. B. Hymenoptera. 12. Bombus terrester Z., skg. C. Lepidoptera. 

 13. Vanessa io Z., skg. 



Loew saw a hover-fly (Helophilus pendulus Z. j and t) in the Berlin Botanic 

 Garden. 



1331. A. abbreviatus Nees. — 



Visitors. — Loew observed the following in the Berlin Botanic Garden. — 



A. Diptera. {a) Muscidae : i. Anthomyia sp. ; 2. Echinomyia fera Z. ; 

 3. Sarcophaga carnaria Z. [b) Syrphidae : 4. Eristalis nemorum Z. ; 5. Syritta 

 pipiens Z. ; 6. Syrphus ribesii Z. B. Hymenoptera. Apidae : 7. Apis mellifica 

 L. 5, skg. and po-dvg. 



1332. A. aziu-eus Lindl. — 



Visitors. — Loew observed the following Diptera in the Berlin Botanic Garden. — 



(a) Muscidae: i. Lucilia caesar Z. (U) Syrphidae: 2. Eristalis aeneus Scop,; 

 3. E. nemorum Z. ; 4. Syrilta pipiens Z. 



1333. A. bnimalis Nees. — 



Visitors. — Loew observed a bee (Halictus leucozonius Schr. J, skg.) in the 

 Berlin Botanic Garden. 



1334. A. concinnus Willd. — 



Visitors. — Loew observed the following in the Berlin Botanic Garden. — 



A. Diptera. (a) Muscidae: i. Anthomyia sp. ; 2. Echinomyia fera Z. 

 (^) Syrphidae : 3. Eristalis aeneus Scop. ; 4. E. tenax Z. ; 5. Melanostoma mellina Z. ; 

 6. Syritta pipiens Z. B. Hymenoptera. (a) Apidae: 7. Apis meUifica Z. 5, skg. 

 and po-cltg. {b) Sphegidae : 8. Ammophila sabulosa Z. 



1335. A. floribundus Willd. — 



Visitors. — Loew observed the follovi-ing in the Berlin Botanic Garden. — 



