6 
Psyche 
[March - June 
nual total of. 18.40 inches (4). In other stations where militicida 
occurs the percentage of spring precipitation is even lower. As the 
spring drought begins, the seed supply reaches its lowest ebb, for 
winter foraging has depleted the meager residue of seeds and no 
more seeds are likely to be set until after the summer rains. These 
unfavorable conditions often lead to a suppression of foraging in the 
spring, but this does not mean that the colony is inactive. For the 
sexual brood is brought to maturity at this time with the marriage 
flight following in early July. Thus the heaviest drain on the supply 
of seeds stored in the nests occurs during the spring months. It is 
at this time that the stored seeds are broken open and the food in 
them is made available to the rapidly developing brood. 
Before taking up the feeding habits of militicida it is advisable to 
discuss certain features of the grass seeds which they use for food. 
At maturity a typical grass seed is enclosed in a complicated envelope 
of bracts. The outermost of these bracts are called glumes, the median 
ones lemmae and the innermost ones paleae. The lemmae often bear 
prominent projecting bristles called awns. These parts are attached, 
close above one another to a much-shortened stem called the rhachilla. 
Collectively these parts make up a spikelet, which may contain one 
or more seeds. As a rule when a mature seed is shed, all of the 
spikelet except the glumes is shed with it. In some grasses this 
envelope fits the seed tightly, which makes its extraction difficult. In 
other grasses the envelope is loosely fitted around the seed and its 
extraction is comparatively easy. The spikelet of E. desvauxii shows 
the first condition, that of T. pulchellus the second. Since most of 
the seeds which the minors of militicida bring back to the nests are 
still in the spikelets, the seeds musts be freed of these envelopes before 
they can be conveniently stored. Observations on the captive colonies 
showed that the seeds of T. pulchellus offer no particular problem 
because of their loose envelopes. The minors have little difficulty in 
pushing the lemmae aside and can often pull out the seeds without de- 
taching the surrounding parts. Perhaps this is why the majors so 
seldom help when pulchellus spikelets are being handled. The spike- 
lets of E. desvauxii are quite another matter. Each of the close-fitting 
lemmae has nine slender awns at its tip. These radiate outward at 
an angle of about 45 degrees and form a complete circle of bristles 
at the upper end of the spikelet. When attempting to free these seeds 
of the envelope both majors and minors will grasp the awns in their 
mandibles. When the major does so the awns are usually broken off, 
but the minor handles them more gently and when two minors grasp 
