PUTNAM ON PULVINARIA INNUMERABILIS. 335 



from one tree to another in the close vicinity, but are not likely to go 

 any great distance in this manner. During the laying and hatching of 

 the eggs the females excrete a quantity of sweetish liquid or honey-dew 

 which is a great attraction to flies, bees, ants, etc., and it very frequently 

 happens that the young lice find their way on to the legs and bodies of 

 these visitors and are thus often carried to a considerable distance. I 

 have several times observed them on the legs of flies taken at a distance 

 from any infested trees. In case a tree or branch should die any time 

 during the summer or fall, or even la the early spring, the females would 

 withdraw their beaks and migrate until they found a fresh supply of 

 suitable food. [In case this migration took place after the leaves had 

 appeared in the spring, it is probable that some of them would settle on 

 the leaves, and thus account for the egg-nests observed on the leaves by 

 Dr. Rathvon, 'and figured by Mr. Riley.] 



It is probably first introduced into new localities on trees which 

 are transplanted from place to place. This also probably accounts in 

 part for its being found more generally on the soft maple, for this has 

 always, in this part of the countuy, been a favorite shade tree for plant- 

 ing in the streets of towns on account of its rapid growth, its beauty and 

 its hardiness. A little care exercised in the examination of trees before 

 planting would in many cases prevent their introduction altogether. 

 With a very little practice an infested tree can be recognized with ease. 



I have observed some peculiar features in their local distribution. 

 During the tliirteen years they have been known in Davenport they have 

 become distributed throughout a radius of less than twenty blocks of -iOU 

 feet each, (a little more than one mile). Yet there are many soft maples 

 within this area that are entirely unaffected by them. One particular 

 case will serve as an example. On the corner of Sixth and Fillmore 

 streets is one of the worst infested trees in the whole city ; during 1877-8 

 it was loaded down with all the Fulvinarice it would bear, and as if this 

 were not enough it was thoroughly infested with a species of AsjncUotus 

 in addition, also by an ^geria and other insects. On each side of 

 this tree is a row of two or three maples of the same age and kind, the 

 two standing next the infested tree actually interlocking branches with 

 it, and yet none of these trees have had more than a few score of Pulvi- 

 nxria females at a time— for all practical purposes, being entirely free 

 from their depleting effects. Other similar cases have been frequently 

 noticed, but the reason of it is unknown to me. 



Another feature of their distribution is that they are of very rare oc- 

 currence in the country, while they become excessively abundant in 

 cities and towns. I may further say I have never seen them upon the 

 soft maple, or any other tree while growing in a state of nature, with the 

 possible exception of one single individual once found on a wild grape 

 vine. The locality of the origin of this species is as yet unknown. Its 

 known range is from Xew York and Maryland on the east, to Minnesota, 

 Iowa, and Missouri on the w^est. 



