The European Corn Borer. 27 
corn borer. The adult or parent of this parasite deposits small 
eges within the eggs of the European corn borer. These parasite 
eggs hatch into small maggots which devour the contents of the 
corn-borer eggs. During the late summer of 1919 an average of 
about 43 per cent and a maximum of 75 per cent of the second- 
generation eggs were parasitized, as shown by egg collections in 23 
towns. In 1921 this parasite destroyed an average of about 30 per 
cent and a maximum of 74 per cent of the corn-borer eggs in 24 
representative towns. This beneficial insect is very variable in 
its occurrence from year to year, as in 1920 only about 6 per cent of 
the second-generation eggs were destroyed in the same area. Less 
than 1 per cent of the first-generation eggs were parasitized each 
year during the period from 1919 to 1921. 
A very small percentage of the borers are destroyed by the young 
or maggots of six different kinds of two-winged parasitic flies.” 
The maggots of these flies feed upon the internal juices and vital 
organs of the living borer and finally cause its death. Less than 1 
per cent of the borers have been destroyed each year by these bene- 
ficial flies. 
Eighteen different kinds of four-winged, wasplike parasites 7° have 
been reared from the larve and pupe of the borer in New England. 
Less than 1 per cent of the borers have been destroyed each year by 
these parasites. 
Some of the parasites which prey upon the borer in Europe have 
been introduced into the infested area of New England from France 
and Italy. The process of establishing these parasites is slow, how- 
ever, and several years will probably elapse before the result of these 
introductions will be known. 
BIRDS. 
A few birds, including blackbirds, woodpeckers, robins, starlings, 
and pheasants, have been known to feed to a shght extent on the 
larvee of the European corn borer in New England.?7 From present 
indications birds can not be expected to cause much reduction in the 
numbers of the pest. 
INSECTS FREQUENTLY MISTAKEN FOR THE EUROPEAN 
CORN BORER. 
Several different kinds of common and native caterpillars are 
frequently mistaken for the European corn borer. Some of these 
caterpillars are similar in appearance to the corn borer, while others 
are quite different in appearance, but the character of their work 
somewhat resembles that of the European corn borer. It is, there- 
* Phorocera erecta Coq, Exorista pyste Walk., Masicera myoidea Desv., Bxorista nigri- 
palpis Towns., Carcelia ochracea V. D. W., and Compsilura concinnata Meig. 
26 Ttoplectis conquisitor Say, Sagaritis dubitatus Cress., Agrypon sp., Amblyteles brevi- 
cinctor Say, Amblyteles rubicundus Cress., Cryptus incertus Cress., Microbracon sp., Mi- 
crogaster zonaria Say, Meteorus loxrostegei Vier., Habrobracon gelechiae Ashm., Epiurus 
pterophori Ashm., Hpiurus tecumseh Vier., Hpiurus indagator Cress., Bassus agilis Cress., 
Labrorychus prismaticus Nort., Ephialtes aequalis Proy., Campoplec sp., and Microbracon 
caulicola Gahan. ‘ 
27 During 1920 the Bureau of Biological Survey investigated the relation of birds to the 
European corn borer in New England. As a result of this investigation, one borer was 
found in the stomach of a pheasant- and six borers in the stomach of a single starling. 
No other species of birds were found to be feeding on the pest at that time. 
