1916] The Citrus Mite 287 



The egg is bright red in color, sphero-lenticular, with a vertical stalk 

 arising from the center of the top side which in length is about twice 

 the diameter of the egg. Several guy fibrils radiate downward from the 

 apex of the stalk to the leaf surface, thus giving additional attachment 

 to the egg. 



Type No. 20362, U. S. Nat. Mus. 



The type material is from Orlando, Florida, March 7, 1916, 

 from the leaves of lemon, collected by W. W. Yothers. The 

 species is in the group containing T. yothersi McG. and a species 

 soon to be described by the author, of the United States, and 

 Paratetranychiis {Tetranychiis) pilosus Zacher (Can. & Fanz.) 

 and P. unungiiis Zacher (Jac.) of Europe. 



NOTES 



Mr. Yothers, who for years has been engaged in studying the 

 entomology of citrus trees in Florida, writes as follows. " Te- 

 tranychus mytilaspidis is most abundant during the spring of 

 the year. I would say its period of maximum occurrence is 

 from the first or middle of December until the first of May. It 

 occurs most abundantly on lemon and sour orange, and it 

 appears in great numbers in nurseries where these species are 

 grown for stock upon which to bud. I have seen it so abundant 

 on sour stock as to cause the stems of the young trees to turn 

 blue for a distance of tW'O feet from the top downward. Its 

 next most favorable food plant is the grapefruit. I rather 

 doubt that it is of any great economic importance on this fruit. 

 It also can be found on sweet orange, but it is of little or no 

 importance on this fruit." 



The citrus mite was introduced into California from Florida 

 on nursery stock about 1890. While the species does not seem 

 to be as injurious in Florida as the so-called 6-spotted mite, its 

 work in California, as early as 1900, was such as to demand 

 urgent action. It is an interesting problem to account for the 

 fact that the citrus red spider is severest as a pest of sweet 

 orange in California, whereas in Florida it all but forsakes the 

 sweet orange and is only severe upon lemon, sour orange, and 

 grapefruit. 



The citrus red spider on orange in California produces a 

 silvering, dwarfing, and dropping of the fruit, and also causes 

 discoloration and dropping of the foliage. It gives trouble in 

 packing houses since it readily attacks the picked fruit. This 

 species is doubtless the most injurious of those found on citrus 

 trees on the Pacific Coast. 



