BEHAVIOR OF SPIDERS AND OTHER INSECTS 417 



During the year Severin and Hartung (84) set free near Hono- 

 lulu 2,000 male Mediterranean fruit flies which had been marked 

 by removing a portion of a leg. Light traps for recapturing 

 them were placed in definite situations. These investigators 

 found that the wind had a marked influence both on the direc- 

 tion of the flight and on the distance flown. In time of calm, 

 the flies flew in all directions, but when the wind was blowing, 

 the flies drifted with it. In no case did they attempt to orient 

 themselves against even the slightest breeze. 



H. Osborn (69) expresses some thoughts on the flight of 

 insects; which reflections he claims are suggestive rather than 

 exhaustive. In the usual explanation of the flight of insects, 

 the mechanism is considered essentially a plane with a rigid 

 anterior border, a flexible hinder border and a vertical move- 

 ment. At each downward stroke of the wings the air in escap- 

 ing backwards and upwards propels the insect forward. Aside 

 from the directly forward flight, insects are able to hover and 

 even to fly backward. Osborn rightly concludes that this hover- 

 ing and this backward flight are not explained by the above 

 formula. He offers the following explanation of hovering and 

 backward flight. There is a forward and backward movement 

 of the wings which permits the angle a wing makes with the 

 body to be varied from 90 to 45 ° or 30 . By this device the 

 rigid por tion of the anterior border of the wing is shifted so that 

 the flexible apical and posterior margins have a different extent 

 and must present a varying pressure upon the air. This rota- 

 tion will allow varying degrees of forward and backward pres- 

 sure. The attitude assumed by the wings of many insects alter 

 death is evidence that such a mechanism actually exists. The 

 extent of the rotation differs in different groups of insects. The 

 shape of the w 7 ing functions also. Broad winged insects neither 

 hover well nor fly backwards well; while narrow winged hexa- 

 pods excel in both styles of flight. 



MISCELLANEOUS INSTINCTS 



In years that are past so many abortive attempts have been 

 made to find a true queen of the common northern termite 

 that many had come to believe there were no true queens in our 

 species. This year, however, such a queen has been found 



