RELATED STUDIES AND CRITIQUES. 181 



were put in a dark-brown bag of gauze and hung above the bed, they were 

 visited by Prosopis and Andrena, but Apis continued to work only on the 

 plants in the bed. In the case of bell-glasses filled with mignonette and one 

 of them inverted, Prosopis and Andrena went only to the one with the open- 

 ing, thus exhibiting the reverse response to odor and color from that of the 

 higher apids. When artificial flowers of Paeonia and Primula were placed 

 in a meadow, 8 Apis went directly to the more conspicuous peony and one 

 each of Apis and Bombus to the primrose. A box was covered on the four 

 sides with differently colored cloths, through which a large opening per- 

 mitted the air to move. When linden flowers were placed on the inside, 

 about 20 individuals of Prosopis went directly in, while 3 Eristalis went first 

 to the color before entering, and 10 to 20 A pis flew against the color alone, 

 especially on the lighted side. With buckwheat substituted for linden, the 

 results were the same, Apis flying to the color and Prosopis entering the 

 box, but when the latter was empty, Prosopis failed to appear, Apis, how- 

 ever, behaving as before. In the case of a choice between the colored bracts 

 of Salvia horminum and artificial cornflowers attached to the plant, the 

 former received 20 visits to 9 for the latter. 



A few weeks later experiments with Dahlia variabilis were made in a 

 garden at Cadenabbia on Lake Como. Four heads were cut off and laid 

 in a pot wrapped with green paper, which was kept covered until the odor 

 had time to collect, and at the same time a large bright-yellow paper flower 

 was fastened to the stem. The pot received no visits, while 19 were made 

 to the imitation, and the results were similar when other paper flowers 

 were employed. When red-brown plums were placed in a pot and also on 

 the ground, the latter alone were visited by honey-bees; with those on the 

 ground removed and the pot in full sunshine the odor of the plums attracted 

 but one bee in the course of an hour. Near a plum tree sought by hundreds 

 of bees was placed a pot wrapped with bright paper and filled with crushed 

 ripe plums, and a paper flower with contrast colors. The latter received 16 

 direct flights, while the former was visited only by young bees that grazed it in 

 flight. In the last experiment with diurnal insects, 50 paper flowers of 

 various colors were fastened to stems of Zinnia elegans, and the normal ones 

 inclosed in wire-gauze to permit the attraction of fragrance alone. However, 

 the latter received no visits, while the former had 49, of which Apis made 

 30, Argynnis 14, Pieris 3, and Vanessa 2, showing that the butterflies be- 

 haved essentially like the higher bees. 



Andreae's conclusions. — It is evident that running insects will have 

 the sense of smell better developed, while flying ones that possess an ex- 

 tended life-period have sight developed in proportion to their rapidity 

 of flight. Thus, it is necessary to distinguish between high and low types, 

 the one characterized by long direct flight, a relatively long life-period, 

 and a keen sense of sight, the other by short flight, short rife-period, marked 

 sense of smell and a poorer vision. Consequently, the various inflores- 

 cences and corollas with bright colors are chiefly adapted to the biologically 

 highly differentiated insects, and the fragrant flowers without bright colors 

 are designed to attract the lower ones. Thus, Prosopis and Andrena react 

 to odors very differently from the higher apids, for, while colors attract 

 Apis, Osmia, Anthophora, and Anthidium from considerable distances, as 



