18 THE SPRING GRAIN-APHIS OE ' ' GREEN BUG." 
hymenopterous parasite, Aphidius sp., and larvae and adults of a 
coccinellid, Adalia favomaculata De G., both of which were observed 
destroying the aphidids. Under date of October 1, 1910, 'Sir. C. P. 
v. d. Merwl, assistant biologist of the same department, stated that 
another outbreak of the pest had taken place that spring and con- 
siderable damage had been done. In this communication the state- 
ment was made that the writer had personal knowledge of the 
occurrence of the species during the past 20 years, and that farmers 
had stated that they had always known of its occurrence in that 
country. It had, however, become seriouslv destructive during: 
recent years and at that time farmers were being forced to give up 
growing wheat extensively on account of its ravages. 
In the Agricultural Journal of India x 'Sir. H. Maxwell-Lefroy, 
government entomologist of British India, stated that the wheat 
aphis (Toxoptera graminum) seeks shelter in the depths of the grass 
roots; hi different ways insects adapt themselves, but these had 
probably done it gradually, moving in from cooler to hotter areas 
step by step. From the illustration of this insect accompanying this 
statement and from specimens later submitted by Mr. Maxwell- 
Lefroy, it has been found impossible to determine the species involved 
as Toxoptera graminum. 
On November 25, 1910, Mr. William Sewall, of Xjoro, British East 
Africa, called at the office of this bureau to complain of the ravages 
of a green louse or fly which attacked and destroyed wheat on his 
farm in the above-named locality, situated almost directly on the 
equator hi a prairie-like country at an elevation of 7,000 feet above 
sea level. A communication was received from Mr. Sewall bearing 
date of August 22, 1911, accompanied by specimens, in which he 
stated that the ravages now extend over an area of 700 acres. He 
also stated that his neighbor, Lord Delamere, who had not been 
troubled previously, experienced severe losses over an area of about 
4,000 acres. The specimens accompanying Mr. SewalTs letter have 
been determined as Toxoptera graminum by Mr. J. T. Monell. 
With these records of the known and probable distribution of 
Toxoptera graminum, it does not seem improbable that if the minute 
insects of the family Aphididae were carefully studied this species 
would be found generally diffused throughout the temperate and 
tropical regions of the world. 
KNOWN DXSTPJBUTION IN THE WESTERN HEMISPHERE. 
With reference to the distribution of tins insect in the Western 
Hemisphere (see fig. 4) , it can be said that it has only been studied in 
the L'nited States. Its occurrence in western Canada is well established. 
On the south it is known along the Mexican border from the Gulf of 
i "Imported insect pests." Agricultural Journal of India, vol. 3, part 3, pp. 243-244, July, 1908. 
