176 ‘The Philippine Journal of Science 1919 
to locate until it has become engorged with blood, an operation 
that takes from nine to fifteen minutes. At present nothing 
is known of its biology, though its larve have been sought for 
since it was first noticed in July, 1915, at the College of Ag- 
riculture, Los Bafios, where it occurred in such large numbers 
as to be an annoyance to the entire community. It is so very 
small that it can easily crawl through the finest mosquito netting; 
and at the time of its great abundance, two and a half years 
ago, blood-filled specimens could be found in the upper corners 
of nets examined in the morning. Its time of first attack is 
from 7 to 8.30 o’clock in the evening, but it may be noted at 
almost any time that the sleeper awakes during the night. It 
is readily attracted to light, and hundreds of specimens were 
found crawling on lamp shades and bamboo walls near the 
electric lights. 
This insect has been collected at no other place in the Phil- 
ippines during sixteen years of entomological work, although 
the name “nicnic” has been heard frequently in connection with 
“a small, invisible ingect that bites in the evening.” Its bite 
is extremely severe, even more painful than that of most mos- 
quitoes, and the wheal remains itchy for a day or more. If 
not satisfied with the first puncture, this fly will repeat the 
act four or five times within an area of a few square milli- 
meters, and the bites are all equally painful. Each bite causes 
a distinct wheal, and sometimes the wheals overlap when fully 
formed. It is not definitely known whether or not both sexes 
bite; but, as their mouth parts are identical in structure, it is 
strongly suspected that they do. 
That these insects might prove a factor in the spread of 
some disease is highly probable, on account of their great abun- 
dance at times and of their persistent manner of attack. 
TRUE FLIES 
The true flies (Muscide), as bloodsuckers, number at least 
five species in three genera in the Philippines. The genus 
Stomoxys contains two species, S. calcitrans L. and S. nigra 
Macq. The former, commonly called the stable fly or biting 
house fly, is by far the commonest bloodsucking fly found in 
these Islands. It is a cosmopolitan species and so closely re- 
sembles the common house fly (Musca domestica L.) that the 
latter is very frequently supposed to be a bloodsucking species.1® 
The larve of this fly feed on a great variety of decom- 
* Bull. N. Y. State Mus. (1917), 194, 20, 
