Mosca has no male form, it would be a female mosca, or a male mosca. That's probably the origin of the mistake with the article. While the gatito example is ok, there is no mosco for mosca.
Outside of your country, mosco is definitely used.
Again, i stated that earlier. They share origin, that doesn't make then mean the same.
I see mosco is definitely used, and rae dictionary has its entrance:
http://lema.rae.es/drae/?val=mosco
Mosco can mean, black horse or mosquito but its NOT the male gender of mosca, that's what i said.
(btw "my" dictionary is the normative spanish by the rae, that also includes south american terms)