. . . and this is the answer . . .

oh well!! this is the answer:
a) there are just more in my house than anywhere else in the known universe
b) this is because i leave the windows open (but it's hot!!)
c) and the light on (but it's dark!)
d) and i haven't used a spray to kill them
e) nor have i swatted them
f) tully hasn't killed them either
g) it has been raining and they have all come inside
h) i am obviously not taking enough care
thanks frankie!! so now i know!!
any other ideas, anyone??