68 THE WEST AMERICA]^ SCIENTIST. 



DODDER IN CALIFORNIA. 



Mr. C. K. Orcutt. 



Dear Sir: — Our secretary, Mr. Breckenfeld, hands me your letter inclos'ng that 

 of Messrs. Vilmorin, Andrieux & Co., and a~ks me to answer: My paper before the 

 Microscopical Society merely explains the microscopic features of the growth of the 

 dodder parasite, as many of our members living in the city had never seen it. There 

 was nothing in it which your distinguished correspondents do not already know. In 

 remarks, I allude I briefly to the spreid of the parasite in this state, where it has 

 given considerable trouble to the growers of alfalfa (medicago sativa). It has ap- 

 peared wherever the growth of this plant has been undertaken — though its appear- 

 ance has been sporadic — ^never affecting all fields in any locality. No effective rem- 

 edy has been discovered save that when only a few plants appear in a field they have 

 been stamped out before see ling by piling straw on and J-round the spot and firing 

 it. Whenever fields have been badly infested they have been plowed up and resown 

 with clean seed. The result is there is very little complaint now heard of the para- 

 site, and our people know it so well that they give it no chance to spread. I believe 

 our California grown alfalfa seed is practically free from dodder seed, and though we 

 have thousands of acres of alfalfa, one does not hear dodder mentioned once now 

 where it was almost a constant subject ten years ago. 



As to the occurrence of dodder in our Eastern states I can say that it is seldom 

 heard of in the red clover regions with which I am acquainted. There was a time 

 some years ago when the do Ider of flax was a serious evil in Missouri, and the flax 

 crop wa i ne irly abandoned because of it, but the flax crop there is now large again. 

 The connecting matter between these two facts I do not know. 



Alfalfa is now one of our great crops in this state, and as I have said the dodder 

 parasite is little heard of. The species of Cuscuta which grow here on salt marsh 

 and on weeds and hillside shrubs do not seem to show any disposition to invade cul- 

 tivated crops. Very respectfully, 



E. J. WiCKSON, 



San Francisco, Calif., June 29, 1886. Editor "Pacific Rural Press." 



AN INSECT MIMIC. 



'Nature' has an article in which the author narrates his observations of an in- 

 sect mimic. He was in Delhi and observed in the sunshine a dipterous insect, as he 

 supposed, upon tne wall. So much it resembled a common house fly feeding upon 

 something stuck upon the wall that naturally flies would be led to the spot to share 

 the food and become an easy prey to this really neuropterous insect of the genus 

 Mantispa, which upon close inspection proved to have four legs instead of six like 

 the fly, and what it appeared to be eating was simply a part of its own substance, 

 •its prothrorax being so curiously modified as to resemble a proboscis. 



The Mantispa somewhat resembles the preying Mantis, though the two insects 

 belono; to different natural or Jers. 



