Insects Injurious to the Mango. 11 
into the tissues of the lower surface of the mango leaf. The writer 
has found that the incubation period requires an average of from 10 
to 15 days. 
The larva—The larva (fig. 5, 2), or young, is about one ninety- 
sixth inch in length upon emergence. It is spindle-shaped, taper- 
ing gradually toward the tail end. The head is rather square, 
rounded in front, with red eyes. The general color is yellow, except 
several segments of the body which are crossed by a bright red 
band and the anal segment, which is red.’ From hatching until 
growth is completed, about 9 to 18 days as a maximum are required, 
depending upon temperature and humidity. The larve feed on the 
leaves in company with the adults and generally prefer the under- 
side, but also may be found on the upper side of the foliage. They 
feed in colonies in folds of the leaf, or along the midrib. As they 
feed the leaf becomes full of minute brown spots where the chloro- 
phyll has been extracted, and in severe cases these run together and 
the entire leaf becomes brown and shriveled. At all times the larva 
holds the tip of the abdomen elevated, and on it a drop of reddish 
liquid, held more or less in place by the stout anal hairs, collects. 
The drop increases in size and falls to the leaf, the surface of which 
finally becomes covered with the excrement, an occurrence also com- 
mon in the case of other thrips. 
The prepupa and pupa.—Like all thrips, the species passes through 
two intermediate stages called the prepupa and the pupa (fig. 5, 
3, 4) before the adult thrips is reached. These two stages do not 
differ materially in structure or appearance. The prepupa meas- 
ures on an average one twenty-fifth inch in length, and the pupa 
approximately the same. The prepupe remain clustered so closely 
that they almost touch and are nearly motionless. If disturbed, 
however, they move rapidly about on the leaf. The prepupe change 
to pupe in the colony of prepupe and larve. When the prepupa is 
ready to molt, the skin is ruptured over the head, gradually worked 
off at the posterior end by contractions of the body, and left behind 
on the leaf. The average period of the prepupa stage was from 
two to five days, depending upon the temperature and humidity. 
The pupz, though possessing the power of motion, are sluggish 
and will not move around unless disturbed. They carry the antennz 
folded back over the head. As the pupe approach maturity their 
bodies begin to turn darker, and just before emergence of the adults 
become almost black. The adults emerge from the pupe in the same 
manner that the younger stages molt; they then move a little way 
off and remain more or less motionless until the chitin hardens. 
Within a day the full colors have developed and the adults begin 
