316 MOSQUITOES OF NORTH AMERICA 
Ashburn and Craig have followed the development of Filaria philippinensis 
in Culex quinquefasciatus but got only negative results with Aédes calopus. 
There appears to be some doubt that this Filaria is a valid species but Looss con- 
siders it distinct. 
Fiilleborn, in his experiments in Germany, used Anopheles maculipennis and 
Aédes calopus. He found that Filaria bancrofti, F. perstans and F. demarquayt 
underwent partial development in the Anopheles and then perished. One Aédes 
calopus showed a developmental stage of Filaria demarquayi in the thoracic 
muscles. With Filaria immitis of the dog Fiilleborn found that Anopheles 
maculipenmis became practically always infected. Aédes calopus became in- 
fected in the proportion of one to five. Nevertheless he found this latter species 
the more satisfactory for experimentation because, in the high temperature 
necessary for the development of the filarie, the Anopheles suffered great 
mortality. 
SUGGESTED RELATIONS OF MOSQUITOES WITH OTHER 
DISEASES, 
While it seems reasonable to suppose that mosquitoes, together with other 
biting insects, may be responsible for the transfer of certain diseases which do 
not necessarily require a secondary host for complete development, such rela- 
tion has never been proved. They have been accused or suspected of being im- 
portant agents in the transfer of leprosy, in the carriage of bubonic plague, of 
tropical ulcer and other skin diseases, of Malta fever, of the horse sickness of 
South Africa, and of other maladies, even of cancer. Some of these diseases 
have never been satisfactorily investigated. With others it has been shown that 
they are transmitted in other ways. Thus bubonic plague is now well known tu 
be transmitted by the bite of certain fleas and Malta fever is acquired through 
the consumption of the milk of goats affected with this disease. 
EFFECT OF MOSQUITO BITES. 
The bite of nearly all mosquitoes causes some irritation but this varies in 
degree with different species and with the individual bitten. It is by no means 
always the largest mosquito which inflicts the most painful bite. Very serious 
results have been attributed to mosquito bites. However, beyond a doubt, when 
serious results follow these are due, not to the bite itself, but to the scratching 
indulged in by the victim. In such cases it is the infection from the finger nails 
which causes the trouble and this may indeed be serious. In sensitive persons 
the inclination to scratch is well-nigh irresistible ; it will, however, be found that 
if one exercises self-control in this respect the effect of even the severest bite will 
pass very quickly. 
Réaumur thought that a poisonous fluid was secreted by the mosquito and 
that its purpose was to cause the blood to flow more readily when it bites. Later 
observers either accepted this statement or denied the existence of such fluid, 
stating that the swelling following the bite was caused by the irritation of the 
puncture without the aid of a poison. Dimmock (1881) convinced himself that 
