78 
unless cannibalistic, selects for its first meal a small tender aphid ; 
under the microscope, one can see the watery juices of the victim bub- 
bling along the transparent jaws of the captor. These larvae are active 
creatures, gray, yellowish, or brownish in color, tho colorless at birth. 
They grow rapidly, and in one to three weeks spin a silken cocoon by 
means of glands opening into the rectum. The cocoon, spherical or 
oval, shows, after the emergence of the adult, a circular lid. 
The Chrysopa larvae are undoubtedly important checks on the 
clover-louse. In red clover I have found three species, namely, ocu- 
lata, plorabunda, and rufilabris. The last was not common ; but the first 
two were numerous, and their larvae were frequently seen feeding on 
M. pisi, upon which we reared them in the insectary. 
A larva of ocuJata, taken July 7, spun July 10 or 11 and gave the 
adult July 27. 
A larva of plorabunda gave precisely the same record. A second 
larva of this species, taken in a colony of M. pisi, spun July 10. in a 
bent leaflet, the adult issuing July 20. 
C. rufilabris emerged July 24 from a cocoon found on a clover 
leaf July 20. 
We have reared no parasites of Chrysopa, but others have ob- 
tained from cocoons of this genus many species of chalcids and a few 
ichneumonids, and from the eggs one proctotrypid. 
The most important of the predaceous foes of the clover-louse be- 
long to the three families just discussed. There remain to be treated, 
several predaceous species of more or less importance. 
While the seed-midge works havoc in the clover heads, another 
member of the same family is busily engaged in reducing the numbers 
of the clover-louse, at least in Canada, for all that we know about this 
helpful but undetermined species of Diplosis is what Dr. Fletcher 
learned at Ottawa, where in 1900 it was by far the most inveterate 
enemy of M. pisi on pea-vines. These minute orange maggots would 
transfix an aphid, hold it up, and suck out the blood, in much the same 
way as the syrphid larvae. Their growth was so rapid as to result in 
several generations during the season. Winter was passed in a minute 
cocoon, spun on the stem of the plant or on the ground among grains 
of sand. 
At Highland, 111., August 11,1 found on the red clover large num- 
bers of both sexes of a tree-cricket [Qlcanthus) , and watched them 
devour the clover-aphid at a great rate. Afterward we kept these 
tree-crickets alive in the insectary for a long time and found it no 
small trouble to keep them supplied with enough plant-lice. Big, as 
compared with their victims, they soon cleaned a plant of aphids. One 
male ate nineteen full-sized aphids at one meal, lasting fifty-five min- 
utes, an aphid being finished in ten to ninety-five seconds, — about one 
louse per minute on an average. In this instance, it should be said, 
Mr. Kelly facilitated matters by handing the cricket a new aphid as 
soon as the old one was finished. The same cricket, on the following 
day, being induced to repeat his performance, beat his previous record 
