i ieaaeeaall 
INSECTS AND DISEASE 
veins extend to the margin of each wing; the top of the thorax does 
not have a distinct V-shaped suture near the middle; the costa (Fig. 
14) continues around the hind margin of the wing; and the wing 
veins bear conspicuous, scale-like hairs. The Culicidae (Mosquitoes) 
are slender; they have long, slender, usually moderately hairy or 
scaly legs; their tibia (the second large joint of the legs) have apical 
spurs; the wings are elongate and narrow. The Psychodidzx (Moth- 
flies) are small and robust; their legs are short and densely hairy; the 
tibia have no apical spurs; the wings are short, broad, and some: 
times pointed apically. The Simuliide and Ceratopogonide 
have more than four distinct longitudinal veins but less than nine 
veins extend to the margin of each wing, and the wings do not have 
a network of fine creases; the costal vein does not continue beyond 
the apex of the wing; and there are no ocelli (small, simple eyes 
which, when present, are situated between, often above, the con- 
spicuous compound eyes). The Simuliide (Black-flies, etc.) are 
usually very small and thick-set; the antenne are shorter than the 
thorax; each antenna is composed of ten or eleven closely united 
segments, not plumose; the hind pair of legs are more or less dilated; 
the anterior veins of the wings are stout, the posterior ones weak. 
The Ceratopogonide (Punkies), like the Chironomidge with which 
they were formerly united but from which they have been separated 
because of their piercing mouth-parts, are slender delicate gnats; the 
antenne are slender, the joints more or less constricted and some: 
times plumose; the femora of the slender legs are sometimes thickened. 
General notions are not always safe guides in the classification of 
insects. However, our general notions as to what a mosquito is, 
combined with the discussion in the preceding paragraph, will prob- 
ably suffice to enable us to recognize a culicid. No male of any 
species of Culicide ever “‘bites.’’ The females of most of the species 
with which we come in contact have the ability and desire to pierce 
the human skin with their needle-like mouths, if they get a chance, 
and to suck a small drop of blood. If this were all they did, it 
would be bad enough, but, when they pierce the skin, they inject an 
irritating substance, saliva, which sometimes “carries with it the 
microscopic, unicellular animals which cause malaria, and down this 
minute, microscopic [salivary] duct has flowed the fluid which has 
altered the fate of continents and played a conspicuous part in the 
destruction of the ancient civilizations of Greece and Rome” 
(Shipley). 
