652 LavuRA FLORENCE 
mature female averages about 4.6 millimeters long by 2.19 millimeters 
at the broadest part of the abdomen, and the male averages about 3.9 mil- 
limeters long by 2.1 millimeters broad. The following table gives the 
average measurements throughout the life history: 
Number 
Age Instar fe Length Breadth 
meena (millimeters) | (millimeters) 
molt 
INewlyalatelediua smi terrae i. deeasen ng een ms 1 0 1.00 0.50 
LON OUTS Aa eee eee ere Peekae ae sc ee 1 3 1.25 0.50 
TNC IRE RUE OUT Mean a cle Say ge VET fe 2 (?) ron 0.75 
SEPA VS Weer er eaia ces eek ee 2 8 2225 1.00 
COT Fe WASTE AKG ine Sa a OA 3 1 2.50 1.00 
AOS cleiy sia sees pees Ae er E ONAN Hy Pata 2 3 3 2.15 125 
WAAAY Sh serie a cane coer eee a ant Shea 4 1 3.00 1.25 
IIS FEU Reta eashiNe sac ior ee ac Gel ed a a 4 4 3.25 1.50 
DSCs EN glove Ronee airs ee Ace neat ch a 4 2° 4.00 2.00 
Meartunetfernales sig iii tis sie Suet Dee 0 ha ete oa [sete ee ees a 4.60 2.19 
Mature inal] ge ay ie a eee CS aA cell Ne tae 3.90 2.10 
In immature lice the lines along which the tegument ruptures at molting 
are very distinct. When about to molt the insect raises itself until only 
the posterior end of the abdomen, and the claws of the second pair of legs, 
are touching the surface on which it rests, the back has a humped appear- 
ance, and the head is bent downward at right angles to the body. The 
first rupture is along the dorsal median line of the thorax and gradually 
extends caudad to the fifth or sixth abdominal segment and cephalad to 
the frons, where it divides, passing to the base of each eye. Air is sucked 
up into the pharynx and passes through the alimentary canal to escape 
at the anus. The body is inflated, pushed through the dorsal ruptures, 
and so drawn away from the old skin. The body is lowered until it 
touches the hair or bristle on which the louse is resting, when the legs are 
folded laterally across it and the ventral surface of the thorax and the 
abdomen (Plate LVIII, 7). The head and the thorax are gradually drawn 
upward until the eyes and the proximal segments of the antennae are 
seen, disclosing at the same time on the old skin a ventral T-shaped 
rupture, the stem of the T lying along the median line from a point midway 
between the bases of the antennae to the prosternum, where there is a 
