Tue Insect FaunA OF THE GENUS CRATAEGUS 1051 
The apple redbug, Heterocordylus malinus, is another hawthorn insect 
which has adopted the apple. It was formerly believed that the false 
apple redbug, Lygidea mendax, was also originally a hawthorn insect, 
but the observations of Cushman (1916), as well as those of the writer, 
indicate that L. mendax is a wild-crab insect and does not feed extensively 
on hawthorns. 
The quince curculio, Conotrachelus crataegi, is a very common feeder 
in haws which has occasionally injured quinces seriously and has thus 
gained its common name. Likewise the lesser apple worm, Laspeyresia 
prunivora, has gained its common name because of occasional migrations 
from hawthorn to apple. 
Baker (1915:10) considers the woolly apple aphis, Eriosoma lanigera, 
to have been originally an elm-Crataegus feeder which has adopted the 
apple and traveled around the world with it. The woolly aphis is undoubt- 
edly common on hawthorns. 
Numerous other native American insects that feed on apple, pear, or 
quince are included in the catalog of hawthorn feeders beginning on 
page 1090. 
The possibility that foreign hawthorn insects may be imported and 
become pests in North America should also be considered. When intro- 
duced into a new environment away from their natural checks, these may 
become more important here. Recent examples of this are three small 
moths imported from Europe — the apple and thorn leaf skeletonizer, 
Simaethis pariana; the hawthorn ermine moth, Yponomeuta padellus; 
and the lesser bud moth, Recurvaria nanella. These have attracted 
the attention of economic entomologists in North America as apple and 
cherry pests, while in Europe they feed commonly on hawthorns. 
Since the catalog of hawthorn insects included in this memoir lists 
their food plants and the continents where each species occurs, further 
examples of foreign hawthorn insects that are now in North America 
may be found there. 
BIOLOGICAL NOTES ON INSECTS FEEDING ON CRATAEGUS, AS OBSERVED 
BY THE WRITER FROM 1917 TO 1920? 
ACARINA 
Tetranychidae 
telarius Linn., Tetranychus (Red spider) 
The leaves of all species of Crataegus observed showed attack by 
Tetranychus telarius. The European hawthorns, however, seem to be 
more often severely injured by these mites than the native species. The 
2 The insects are grouped according to order and family, and arranged alphabetically by species within 
the family. 
