1914] Smith—The Development of Anopheles punctipennis Say 9 
hairs from the sides of the head, outside the antennz, are rela- 
tively longer than in any succeeding stage. The six bristles across 
the dorsal surface of the head (a) are unbranched, as are the two 
hairs which lie between the brushes and the central terminal hairs, 
which remain unbranched throughout the larval life. 
The most conspicuous structures of the head of the young larva 
are the long simple hairs on the top, and the long lateral hairs 
at the side of the head, which with hairs of the antennz form a 
barricade. Four simple hairs and the absence of a rudder-like 
tuft on the ninth segment (a) of the abdomen, are characteristic 
of the first stage. 
When about two days old the larva will have changed con- 
siderably in appearance. It will measure by this time about 1.5 
mm. in length. The thorax will have become distinctly formed 
and the long hairs will appear somewhat shorter. The head will 
have quite a different shape from that of the larva of one day. It 
will have become very dark, especially the “collar”? which will be 
almost black. The head is much narrower and deeper. The 
integument has a snug, tight-fitting look (fig. 3). This figure 
shows a larva in the act of molting for the first time. In this case 
it died in the process, the integument of the thorax having failed 
to split apart. 
For some time previous to each of the molting processes in the 
larval life, the head shows this peculiar narrowing, with the in- 
creased width and deepening color of the “collar.” “The larva 
measures just the same after the molting process as before it. In 
this case it was 1.5 mm. 
Second Stage of the Larva. The changes at the time of the first 
molting are conspicuous. Although the thorax is distinct and 
large, the head is even larger (fig. 4). The four dorsal hairs of 
the posterior end have become eight (a), and the ventral tuft (b) 
has appeared, consisting of two rows of long branched hairs with 
a fan-like arrangement. On the head the simple hair just inside 
of each rotary brush (d) has become much branched, and is used 
for combing out the brush. The six simple hairs lying back of 
the brushes, on the top of the head, have become very much 
branched. The eyes are still little developed. 
The yellow spots on the dorsal surface have increased in number 
and density, being most conspicuous on the third, fifth, and eighth 
segments of the abdomen, and on the thorax. 
