150 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
adjacent walls of the head, but I am not certain whether the muscle 
is augmented by these fibers or instead partially inserts on the wall 
of the head. 
The maxillae of the male mosquito are no stronger than the man¬ 
dibles of the female, but the maxillae of the latter sex are powerful 
cutting lancets, armed near the apex with recurved teeth along the 
outer border of the blade. This border is thin and its chitinous cuti¬ 
cle is delicate. The inner border of the blade is broad and its chitin 
is thick (pi. 16, fig. 47). Proximally, the inner border terminates 
with an articular spur. From the point where the palp and the 
outer border of the maxilla blade unite, an apodeme enters the head 
and extends almost to the occipital foramen (pi. 12, fig. 2, apo). 
The maxillae have a complex musculature which must ensure a con¬ 
siderable freedom of movement, although it is possible to assign 
functions to the different muscles only in a general way (pi. 12, 
fig. 2; pi. 13). The most prominent muscle in sections lies parallel 
to and outside of the maxillary apodeme. It arises from the under 
side of the lower end of the tentorium and the adjacent walls of 
the head and is inserted on the base of the palp and apodeme. 
While the general action of the muscle must be the retraction of 
the maxilla, it would seem that it will also tend to divaricate 
maxilla and palpus. To adopt Dimmock’s (’81) and Nuttall and 
Shipley’s (: 01- : 03) name, this muscle is the retractor of the max¬ 
illa. Another important muscle arises from the “ head ” of the 
tentorium and is inserted on the articular spur of the maxilla. As 
it also sends fibers to the dorsal angles of the base of the labium, I 
call this muscle the double retractor. From its position it is prob¬ 
ably the chief retractor of the maxilla blade, which cuts on the up 
stroke. It has an extensive tracheal supply. 
Two pairs of muscles are found which probably serve to protract 
the maxillae. The larger of these, the protractors of the maxillae, 
are inserted on the free ends of the apodemes (prot max ) and extend 
forward, inward, and upward to the tentoria. The origin is from 
the under surface of the strut just below the “head.” The smaller 
pair of muscles, the maxillo-labials ( max-li ), are inserted towards 
the ends of the apodemes, and run forward along the inner side of 
the apodemes to the ventral border of the labium. In addition to 
these larger muscles, each maxilla receives on the articular spur a 
short band of fibers from the adjacent wall of the pharynx. Per- 
