1955] 
Brooks — Fossil Galls 
7 
Not only does the leaf of Nectandra pseudocoriacea 
figured on plate 1, fig. 7, bear the results of the activity 
of some leaf-eating organism, presumably an insect, but 
the remaining part of the leaf bears eleven well preserved 
“cone” galls (fig. 7a). The structures are mammilliform 
and seem to be separated from the leaf by a constriction 
at the point of attachment. They are elliptical at the base, 
1 mm. by 0.8 mm., and taper to a blunt apex about 0.4 mm. 
above the surface of the leaf. Immediately surrounding 
the galls, the leaves are darkened. The darkened areas 
probably reflect sclerotized leaf tissue in the vicinity of 
the galls as the coloration is due to a greater amount of 
lignitized leaf residue. 
These “cone” galls are comparable in size and general 
shape to some Recent galls induced to develop on leaves 
by gall mites (Eriophyidae) , plant lice (Phylloxeridae) 
and especially by gall midges (Cecidomyiidae=Itonididae) 
and by gall wasps (Cynipidae). The sclerotized leaf tissue 
surrounding the galls is suggestive of Recent “leaf spot 
galls” produced by the gall midge, Cecidomyia ocellaris 
on maple leaves (Felt, 1940, fig. 258). 
Neither of the alleged insect galls described and figured 
by Berry (1916, pi. Ill, fig. 1, and pi. 56, fig. 2) is similar 
to the structures described above. One consists of small, 
deep, conical depressions on the impression of a leaf and 
the other is a compression of a petiole gall. Both figured 
specimens seem to bear authentic galls. 
Though binomial names have been proposed by Cock- 
erell (1908) and Brues (1910) for fossil galls, it is believed 
that no useful purpose is served by naming such objects. 
Gall forming arthropods are small and fragile and thus 
there is an extremely meager fossil record of their remains. 
The reported stratigraphic ranges of the families mentioned 
above are as follows: 
Class Arachnida 
Order Acarina, Family Eriophyidae, no fossils 
Class Insecta 
Order Hemiptera, Family Phylloxeridae, no fossils 
Family Chermidae, Oligocene to Recent (Hand- 
lirsch, 1921). 
