1918] W ELLS—ZOOCECIDIA 537 
unsatisfactory are the data. in innumerable specific instances, that 
at the present time any generalizations of a numerical nature 
cannot be accepted as expressing the exact condition. 
A tabulated statement of the 792 galls known from the north- 
eastern quarter of the United States and eastern Canada, according 
to the cecidozoon orders and families, is as follows: 
DISTRIBUTION BY ANIMAL FAMILIES 
Nematoidea (Nematohelminthes) Cplecaiae 3 oo es os ie Aaa 3 
Anguillulidae: 256500) See 2 Blachistidaes oes 36 604 x 2 
Acarida rage Maia oe Bie oes, I 
Ptwohivadee oo 87 DOrbniciaae 6 eek a 2 
Hemiptera as Waclaaiied: ooo 10 
Apakudae. See ee 70 
Fee eee ae ee eee 7 
MOG Gace ek I SOGRIINIAS os ssc es 383 
Coleoptera Hymenoptera 
etambviidas, 5 ee 2 Chalcidaee Pus eat 2 
muptentidats oS ce I SORUTMMIR  i os asc s & 13 
Lepidoptera RVOUANNE 255i os ch eee ee 194 
As FELT has pointed out, the family containing the most gall 
makers is the Itonididae, embracing in our region 47 per cent of the 
gall biota. The Cynipidae follow with 37 per cent. The other 
families are represented by much smaller percentages, the Coleop- 
tera being barely represented with 3 ill-defined galls. 
The distribution of the galls (except nematode) by the plant 
families on whose members they occur is as follows. The families 
are arranged in the sequence given in GRAY’s Manual. 
DISTRIBUTION BY PLANT FAMILIES 
Pinaceae... 63.6, |; 13 Aristolochiaceae...... a Rosaceae, 0, 79 
Typhareee. <5. 5. Polygonaceae........ 2 Leguminosae......... 18 
Gramineae........... 5 Chenopodiaceae... ... 5 Euphorbiaceae....... 4 
Cyperacese.- 205... 1 Nyctaginaceae....... 1 Anac CRs OS 10 
sincatede 1 Portulacaceae........ 1 Aquifoliaceae........ I 
OCC eo. go Ranunculaceae....... + Celnstracese......:.. I 
Midaceae) 65.0 t Magnoliaceae........ 2 Acemcesae. 2... .0. 14 
Salicacese, 2... 2, 60 La oe ee ee s Balsaminaceae....... 3 
Juglandaceae........ 64 Papaveraceae........ 1 Rhamnaceae......... 2 
Betulacess: 25 cc. S Croctietee. 2... ss i VIBORRES ig owes. 20 
Fa, AGACERE. ... 8... 483 Saxilragaceae........: a SUMMER Sc ess 7 
