194 MAINE AGRICULTURAL EXPERIMENT STATION. IQIO. 



separate these species, but as the venation runs constant in 

 certain large cohections it seems expedient to consider them 

 as distinct unless future study shall show them to be dimorphic 

 forms of the same species. 



There can be no doubt that Tetraneura colophoidea is the 

 elm gall form of graminis (.on grass). Similarly there seems 

 no longer any reason to hold Colopha eragrostidis (on grass) 

 distinct from ulmicola of the elm. 



Tetraneura ulmisacculi is described as a new species. It may 

 prove to be a European species. It accords fairly well with 

 Buckton's* characterization of Tetraneura ulmi both as to gall 

 and insect. It does not accord with Lichtenstein's character- 

 ization of ulrni^ nor alba.'f The gall would preclude it from 

 rubra, and as the European literature is not entirely clear for 

 the species of Tetraneura it seems expedient to consider ulmi- 

 sacculi as distinct from European species unless it can be defi- 

 nitely shown to be the same. 



Tetraneura ulmi has been several times recorded for America 

 but, except for some introduced specimens^ which died out 

 after the first year, there is no reason for considering these 

 records as authentic for that species. 



Schizoneura americana is by some considered the same as 

 the European Schisoneura ulmi. If not the same it is cer- 

 tainly very closely allied. The fate of the migrants of this 

 species has never been clearly followed. I find no recognizable 

 constant dififerences between americana of the elm leaf curl and 

 rileyi of the elm trunk and branch, and consider them possibly 

 to be the same species. Biological proof of this is lacking. 



The gall of Pemphigits ulmifiisus was described by Walsh 

 40 years ago but except for a few words and comment at that 

 time the insect was never characterized at all until it was de- 

 scribed and figured from a specimen with freak venation as 

 Schisoneura sp.§ in 1904. 



The present bulletin indicates the following unsolved or part- 

 \y solved problems for the gall aphids of the elm. 



*British Aphides. 



tLes Pucerons des Ormeaux. 



IMonell, Can. Ent. Vol. 14, p. 16/ 



§Sanborn, Kansas Aphid, p. 28 and Plate VI, fig. 41. 



