44 INSECTS AFFECTING THE ORANGE. 



in search of such lurking places, however readily they accept the pro- 

 tection when found. 



Theobserved fact that Scale-insects spread most rapidly .in the direction 

 of prevailing winds has often been verified, and has led to the belief 

 in direct transportation by the winds, as the most important agency in 

 their dissemination. This popular theory is thus stated by a writer: 

 4 - Now, in the spring and fail, just when the insects are hatching and 

 most numerous, we have our heaviest- storms. * ,* * During 

 one of these storms I have often seen leaves, twigs, and sometimes 

 whole branches taken up and carried whii ling through t hi* air for a 

 quarter of a mile or further. Ilo\v easy, then, would it be for these 

 microscopical insects, but a few atoms in weight, to becai ried lor miles."* 



The gentle southeast trade-winds of Florida and the storms which 

 are occasional, and, fortunately, somewhat lare visitants, are very 

 different phenomena. While the influence of the former is sometimes 

 seen in the more rapid spread of the Scale-insects towards the north- 

 west it has never been observed that a sudden extension of the pest 

 has followed any of the violent or long-continued wind storms on record. 



That tempest-borne branches and leaves might carry the infection 

 to a distance cannot of course be denied, but the dissemination of Scale- 

 insects, continues without Interruption at all seasons and in all parts 

 of the State, a process of such constancy and regularity, cannot be 

 attributed in any great measure to the fitful agency of occasional storms. 



Nor can it be by direct transportation that the trade-winds assist in 

 spreading Scale insects, for winds of moderate force are not competent 

 to dislodge -the young lice from the plants. Of this any one may be 

 convinced by trial with a bellows or with the breath. Minute and in- 

 significant in weight though they are, they cling with tenacity to the 

 bark, and the pressure of uir upon their thin bodies only serves to press 

 them into closer contact with the surface. 



It is rather to the indirect action of the wind, to the influence which 

 it exerts upon the flight of insects and other winged animals which 

 transport. Scale insects, that we must look for an explanation of the ob- 

 served phenomena. 



And particularly is this influence of the wind felt in the case of spiders, 

 most of the-species of which are dependent upon the wind in their mi- 

 grations. For, although wingless, they are enabled by means of the 

 buoyancy of their web and the power which they possess of reeling it 

 out upon the wind to bsidgc long gaps from tree to tree, and even to 

 copy the flight of winged animals. 



The goss.imer spider makes its aerial voyages by clinging to a light 

 tangle of web, on which, as by a parachute, it is borne to gieat distances 

 by the wind. 



Many species have this habit of the gossamer. Some, however, use, 

 instead of a tangle, long lines of web which are cast out upon the wind 

 to a distance of several hundred feet, until their buoyancy becomes 



* Ashiiieud, Orau^c Insects, page 3. 



