_ AMERICAN MUSEUM GUIDE LEAFLETS 

THE MOSQUITOES AND THEIR ALLIES 
The blood-sucking habit, and the modifications of mouth-parts 
necessary to such a habit, are to be found in several, not closely re- 
lated, Sroups of the two-winged insects, Diptera. All blood-suckers 
are to be looked on with suspicion, because of the possibility that 
they may be the intermediate hosts of disease-parasites. Several such 
insects have already been mentioned; but another group of quite 
different creatures remains to be discussed. 
If a moquito, crane fly, or some similar insect, be carefully ex- 
amined, it will be seen that the antenne (“‘feelers’’) consist of not 
less than eight joints, rather similar one to another; the antennz are 
usually longer than the thorax (the middle part of the body, the part 
which bears the wings and legs); the anal cell (see Fig. 14) is rarely 
narrowed in the border of the wing and the discal cell is usually 
absent. These are distinguishing characteristics of the nematocerous 
Diptera or Orthorrhapha, that group of Diptera to which mosquitoes, 
punkies, black flies, and blood-sucking gnats in general belong. 

Sone 
ee a Ep 
ELE SS SS i 
oF SSeS 
aA ye S y WSs. 
1 \ < 
RIS 
Fig. 14. STRUCTURAL CHARACTERS OF THE MOSQUITO 
a. Antenna 6. Thorax 
¢. Costal vein of wing d. Anal cell 
e. Tibia 
Of the Nematocera, there are four families (Culicide, Psycho- 
did, Simuliide, and Ceratopogonidz) which contain blood-sucking 
species. The adults of the first two of these, Culicide and Psychodide, 
unite in typically having the following characteristics: at least nine 
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