338 JOURNAL OF ECONOMIC ENTOMOLOGY (Vol. 4 



and later investigations throughout the state proved that this species 

 and not T. gloveri was doing a great amount of damage. Now the 

 question arises as to which species is really the cotton red spider. My 

 observations show that in 1910 in South Carolina the damage to 

 cotton was altogether by T. himaculatus. In fact that was the only 

 species of Tetranychus found upon any plants. 



Regarding T. himaculatus, which I have collected in South Carolina. 

 District of Columbia, Illinois, and Oregon, and which has been reported 

 from Maine, Florida, Colorado, etc., the probability arises that this 

 mite belongs to one of the several common European species. There 

 seems a great likelihood that it has been gradually spread over the 

 United States by greenhouse plants in the southern states, especially 

 by violets, which are favorite ornamental plants for dooryards. 

 They remain green throughout the year and afford a fine winter shelter 

 for the mites. Mr. Banks (Proc. Acad. Nat. Sci., Phila., 1901, p. 596) 

 has, in fact, pointed out that this was probably the way in which the 

 mite was introduced into New Mexico. 



The eggs are not deposited in masses on the leaves but usually 

 within a certain area. Oftentimes the female will leave the original 

 starting place and so form two colonies on the same leaf. Probably in 

 every case a web of fine silk-like threads will be found over the eggs 

 with occasional eggs in the web. The eggs when first deposited are 

 like clear drops of water but soon turn reddish and sometimes become 

 dark red. Upon hatching the young mites are colorless, very hard to 

 see, and have but three pairs of legs, the fourth pair appearing after 

 the first molt. 



Shortly after hatching the very small mites appear dark green and 

 are so near the color of the leaf that only continued search will reveal 

 them. The first molt takes place in about two days after hatching 

 and after that one can hardly note the molts on account of the pres- 

 ence of the cast skins of the young. There seems to be four molts 

 betw^een eggs and adult. When ready to molt the fourth time the 

 mites are probably full grown and they do not increase in size after 

 molting the last time. 



They probably go down to the crown of the plant during cold weather, 

 migrating back to the leaves with the return of rising temperature. 

 From these they migrate to other plants and into cotton fields where 

 they create great havoc in a very short time. 



In making notes on life history single females were placed on indi- 

 vidual leaves. These records show that in May the length of the 

 egg stage is greater than during the months of June and July, the 

 maximum number of days from deposition to hatching being six- 

 teen and the minimum seven, average thirteen. During June the 



