PROBOSCIS OF MALE 43 
males have been distinguished from the females, by all scientific entomological 
ue on the subject, by means of their feather-like antenne and maxillary 
palpi. 
“The proboscis of the male of Culex pipiens, the only species the male of 
which I have studied, is slightly longer and slenderer than the corresponding 
organ inthe female. The sete are fewer in number and less completely sheathed 
by the labium than in the female; they consist of a well-developed labrum-epi- 
pharynx and two slightly developed maxilla. The mandibles are absent, and 
the hypopharynx coalesces with the labium (fig. 12 h and /). The labium and 
maxillary palpi are more densely covered with hair and scales than they are in 
the females, and they contain muscles; the other mouth-parts, the sete proper, 
are naked, chitinous, and contain no muscles. In comparative length the mouth- 
parts may be arranged, longest first: maxillary palpi, labium and labrum-epi- 
pharynx, maxilla ;—in comparative size they may be arranged, largest first : 
labium, maxillary palpi, labrum-epipharynx, maxille. The relative position of 
the mouth-parts of the male is different from that in the female (compare figs. 
8-9 with 13-15) in that the short, rudimentary maxille are pushed out sidewise 
to allow the hypopharynx to coalesce with the labium. In the male the cesoph- 
ageal pump, or bulb behind the nerve-ring, fails, and the sucking of fluids 
must be done by the pharynx alone, as it is done in most diptera. 
“ The labrum-epipharynx is nearly the same in general form and structure in 
the male Culez as it is in the female, it is a trifle longer and slenderer, but the 
same figures (5, Ir-e, and 6) will serve for the tips of both. In section (fig. 12, 
lr-e), the labrum shows a groove on its upper surface, which deepens as it nears 
the base (fig. 13, Ir-e). The apical four-fifths of the labium contains no other 
seta than the labrum-epipharynx, as seen in fig. 12, which is a section at about 
the middle of the proboscis. At the base of the labrum-epipharynx are pharyn- 
geal muscles similar to those found in the female, and with similar insertions 
and origins, except that the median muscle (fig. 15, pm’) is not divided into 
three parts as in the female (fig. 9, pm’). 
“ The hypopharynx is, throughout its whole length, joined to the labium, and 
thus necessarily pushes the maxille, which would normally lie between it and 
the labium, to one side. (See fig. 13, 4 and mz.) The hypopharynx shows, in 
section (fig. 18-15, h), the same chitinous rod through the middle as in the 
females, but I was unable to detect any channel for saliva through this rod. 
“The maxille are very thin lamelle of transparent chitin, about one-fifth as 
long as the labium, and so delicate as to be easily overlooked. Although as broad 
at the base as is the tube of the epipharynx, they taper regularly from their base 
to their fine tips. 
“The maxillary palpi are five-jointed, very hairy toward the tip, much longer 
than they are in the female, and when at rest their basal portions cover the 
labrum-epipharynx and maxilla in the sheath of the labium. 
“The labium of the male Culex is similar in general structure to that of the 
female, if one considers it together with the hypopharynx. It is, however, 
slenderer, more densely covered with scales, has a shallower groove for the recep- 
tion of the labrum-epipharynx, and has a joint near the middle. The slender- 
ness of the labium in the male extends itself to the labelle. (Compare fig. 4, 1b, 
with fig. 3,7b). The groove of the labium of the male increases in shallowness 
from tip to base; at the middle of the proboscis (fig. 12) it is so shallow that it 
fails to fully protect the labrum-epipharynx, and at its base (fig. 13) it is so 
shallow that the other mouth-parts rest only on top of the labium. To make up 
for this deficiency of protection by the labium, the maxillary palpi, as was pre- 
viously mentioned, cover over the upper side of the enclosed parts (see fig. 13), 
and thus, although free from the labium, form a part of the protective sheath, 
