INSECTS AFFECTING PARK AND WOODLAND TREES 633 



The development of the gall is interesting. It appears to be formed 

 by the irritation due to one or more larvae on the upper surface of the 

 midrib of the leaflet? The longer, more conspicuous galls are inhabited by 

 a considerable number, while smaller ones may contain only one or two or 

 three larvae. In each instance it will be observed that the tissues on either 

 side of the midrib and including it to some extent, begin to swell enor- 

 mously, thicken and gradually close over the irritating larva. The fly has 

 not been bred, due to the rapid withering of the gall, in spite of several 

 attempts to obtain the adult. When young, the gall is a pale green 

 and as it ages it becomes tinged with brown. It is thick and the hyper- 

 trophied tissue is very succulent [fig. J 69]. This species has been recorded 

 by Professor Beutenmuller from Fort Lee N. J., where it occurs in June. 



Red elm leaf gall. Pemphigus zclmifusus Walsh. The solitary spindle- 

 shaped galls produced by this plant louse on the upper surface of the leaves 

 of the red elm, are about an inch long. This species is rare in New York 

 State. It occurs in small numbers on slippery-elm. 



Ash flower gall 



Eriophycs fraxiniflora n. sp. 

 The staminate flowers of white ash are sometimes very curiously 

 deformed by the work of a small gall mite, which appears to attack them 

 about the time they begin to develop, and by the latter part of June 

 peculiar irregular masses of green tissues are found on the flower stem. 

 An examination shows that each mass consists of a series of irregular, 

 fringed, lobulated masses joined one to the other, each group at this time 

 ranging from ]^ to about inch in diameter. Later they become nearly 

 inch or more in diameter, eventually drying and remaining on the trees 

 over winter, giving the infested ones a very peculiar appearance. The 

 work of this mite appears to be moderately common in New York State, 

 though it does not seem to have attracted much attention. Specimens of 

 this mite's work have been received from Brooklyn N. Y. where it appears 

 to infest several trees year after year, and we have also observed its 



