326 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 7 



cation of the hydro-locomotion idea comes about, then, as follows: 

 Battered to the ground by a heavy downpour of rain, countless thou- 

 sands of mites are carried along in the tiny streamlets which form at 

 such times between crop rows, and may even find their way into the 

 smaller creeks. Provided, thus, that the duration of submergence 

 does not reach nine hours, or that the individual receives no fatal 

 buffeting on its journey, it will shortly revive upon becoming stranded 

 and estabhsh itself anew^ — perhaps many rods from its place of detach- 

 ment. 



li^ The activity of the red spider during the winter constitutes a two- 

 horned factor, the relative economic status of which is not at once 

 determinable. The fact that the adult mites are not compelled to 

 hibernate bepeaks graphically the hardiness of the species, and holds 

 out little encouragement for the decimation of the pest through the 

 inimical agency of minimum temperatures. On the other hand, the 

 occurrence in the winter of the mites in the active state enables the 

 planter to concentrate his combative efforts at a time when the pest 

 is reduced in number to a minimum. In short, this condition leaves 

 the red spiders in the winter period where they can be easily found 

 and combated by human agencies if so desired. It is a question 

 whether more good or more harm comes, economically, from the attri- 

 bute of winter activity on the part of the pest. 



The non-roving disposition of the red spider is another character- 

 istic which is both to the detriment and the advantage of the farmer, 

 dejDending on the viewpoint. From the fact that mite individuals 

 usually attain maturity on the identical leaf which harbored them at 

 birth, and are suctorial in nature, it is obvious that spraying operations 

 are complicated to the extent that the applications, to be effective, 

 must be made in such a way as to come in contact with every portion 

 of the infested foliage. This necessarily increases the cost of spraying 

 until the outlay constitutes a considerable proportion of the value of 

 such a comparatively non-valuable crop as cotton. On the other 

 hand, the aversion of the red spiders to moving about has a retarding 

 influence on dispersion and, although it tends to concentrate the at- 

 tack where present, is decidedly unfavorable to the rapid dissemination 

 of the pest. The aggregate result of the non-roving attribute, coupled 

 with the absence of the power of flight, is that infestation is never 

 continuous over large areas, but is restricted to limited areas with 

 their respective sources as centers. These infested areas occur, fig- 

 uratively, as countless islands in a sea of immunity. From this, it is 

 easy to see that, to a great extent, every man's problem is virtually 

 his own. Hence, if infestation comes from a certain spot upon one's 

 premises, proper attention to such a source will yield satisfactory 

 results in spite of the negligence of one's neighbors. 



