The Ancient Han called themselves "Hua Xia"(or "Zhu Xia",ie all of Xia). "Hua" means prosperity/glory, "Xia" means "Men of Zhong Guo" .("Zhong Guo" translate as "Middle Kingdom"/"Central state")
3000 years ago, the term "Zhong Guo" already appeared from the early period of the Zhou Dynasty, it can be substituted with another term "Zhong Yuan", they were geo- cultural and political terms determined an area,which makes today's He Nan province in central China. The terms reflect that the core of Chinese cultural dominance, from its ruling center around the city of LuoYang, extending to the whole of middle reaches of the Yellow river. In 1965, bronze vessels belong to the king "Cheng"of Zhou dynasty were unearthed in ShannXi province( North-west to He Nan province), from the inscription on the bronze ware, came across the phrase "Zhai Zi Zhong Guo", which means "move residence to Zhong Guo". which accord with historical records, that state " the King Cheng of Zhou dynasty want to follow his predecessor king Wu's will, to move Zhou capital to the centre of the "world"(TianXia), and rule."
And some believe the term " Hua Xia", derived from geographical origin, that identify "Hua" with Mountain Hua in ShannXi province, which was the area that harbored the Yang Shao culture of China, and identify "Xia" with river Xia, in ShanXi(a different province next to ShannXi) province's south west region, which was ancient Xia people's settlement area. From the inscriptions on Shang dynasty oracle bones, the characters of both "Hua" and "Xia" have grand meaning, they were highly praised gods along with another god "He"(means river), according to ancient legend, "He" splits "Hua" and "Xia", the 3 gods were altogether addressed in oracle reading by the Shang.
The geographical meaning of "Hua Xia" was the core area where the legendary pre-history sovereigns, Yao, Shun, great Yu, along with Shang and Zhou dynasties ruled. It is the "Zhong Tu"(middle earth), thus "Hua Xia" transform into "Zhong Guo", as opposed to the usage of terms like "Si Fang" and "Si Yi", i.e uncivilized barbarians (non-Chinese) around the "Middle kingdom" (the Chinese)
Today, "Si Fang" literally mean four directions, thus "Dong Fang"(east),"Xi Fang"(west),"Nan Fang"(south),"Bei Fang"(north) in Mandarin. But when the King WuDing of Shang dynasty and his queen FuHao battled the barbarians called "Tu Fang" and "Qiang Fang" to the north-west, Usage of Fang(Si Fang) must had similar meaning to that of Yi, as the terms "Si Fang" and "Si Yi" were to express a same definition," barbarians around in four directions ".
In ancient text, "Hua" and "Xia" both meaning the Chinese and their kingdoms,states,clans etc, whereas the term "Man" and "Yi" were refering the non-Chinese barbarians.
In one historical records from the Spring & autumn period, "the armies of Kingdom Lu and Qi fought each other at a place called JiaGu, the sovereign of Qi called the help of local Lai tribe to attack the sovereign of Lu. Confucius condemed this action by saying"if its not the descendants of Xia themselves fought each other, the Barbarian Yi would never disrupt the land of Hua"".
Confucius had good reason for that, as he himself was descended from royal line of Song Kingdom, whom themselves before the establishment of Zhou dynasty were once the ruling class of Shang dynasty. And the founder of Lu kingdom was JiDan or ZhouGong ( Duke of Zhou), brother to the King Wu of Zhou, and the man responsible for split the land under Zhou rule into many feudal kingdoms, Confucius revered him and called ZhouGong a saint. The founder of Qi kingdom was JiangShang, supreme advicer to the founding king of Zhou dynasty, who helped the king to overthrew the Shang, and was rewarded with the land of Qi.
Today, Han Chinese still call themselves "Scions of the Yellow emperor and the Fire emperor".
The founders of ancient Xia, Shang, Zhou dynasties were from "HuaXia" group, First king of Xia, King Qi(which literally means begining) was the son of the legendary sage sovereign "Great Yu",

who battled the floods and revered by "HuaXia" to these days. Before Qi, the working chief examines certain outstanding personage, as majority of the Clans agreed, the person then was elected as the new chief of the HuaXia, because of Yu's deeds battling the floods, he was chosen by the former chief Shun. But after Yu's death, Qi abolished this custom, the YouHu clan objected this change, and was defeated by Qi's force, thus establish the first Chinese dynasty, Xia.
Qi rewarded the Zi clan whom helped his father "the great Yu" battle the floods, a land to rule. The Zi later overthrew the Xia, and founded the Shang Dynasty by Tang , the first king of Shang.
The Zhou was a vassel state to the Shang, their royal line had the surname of Ji, which was the surname of the Yellow emperor. Xia, Shang, Zhou dynasties were all founded by HuaXia, thus by the "Scions of the Yellow emperor and the Fire emperor".
The HuaXia revered both " the Yellow emperor" and " the Fire Emperor".
This is the Han dynasty wall carving depicting the Yellow emperor

and his wife Lei Zu (inventor of Silk), a Northern Zhou dynasty statuary of her

HuangDi(the yellow emperor) had the surname of Ji, also called by clan Xuan Yuan or YouXiong, son of ShaoDian. He possess of the virtue of earth, since earth is yellow, thus the name HuangDi, meaning the Yellow emperor. By defeating YanDi(the Fire emperor) at the battle of BanQuan, YanDi agreed to surrender and form with HuangDi the Yan-Huang alliance, where the "scions of the Yellow and Fire emperors" came to be.
HuangDi then defeated the JiuLi tribe under the leadership of ChiYou at the battle of ZhuoLu. He had ChiYou's head cut off, part of JiuLi fled to south, while part of them were incorporated into the Yan-Huang group. By these victories, HuangDi was chosen by the rest, as the common leader of all tribes.
HuangDi gave many contributions to the HuaXia, including silk production, building of ships and vehicles, Chinese letter, musics,mathematics,medicine etc. He had twenty five sons, fourteen of them were granted with surnames, altogether twelve. He was buried at QiaoShan(today HuangLing county in ShannXi province) after he passed away.
Through the millennia, the land around his mausoleum see the rise and fall of many dynasties, because of these intense human activities, that as much as 90% of the land was once covered with vegetation now became wasted. Only at the mausoleum of the Yellow emperor, one might get a glimpse of what was the land look like back in the millennia, there are cypress trees(sign of condolence) more than 2500 years old, there are fountains to be found only around his mausoleum. No one dared to disturb the place, that its ecological environment is preserved through the millennia.
Lei Zu was the daughter of XiLing clan, she born HuangDi a son named ChangYi, whom became the ancester of YouYu clan and the Xia dynasty. Another son of theirs XuanXiao became the ancester of the Shang and Zhou dynasty.
YanDi, or the Fire emperor,

was the leader of a tribe which had the surname of Jiang. Also called ChiDi, LieShan clan, or some say hes the same as the legendary ShenNong (whos the inventor of Chinese agriculture and medicine)

YanDi's mother was named RenSi, one day she was on tour of Mountain Hua, after seeing a divine dragon, she felt strange of her body, upon return she gave birth to a son, whom is the YanDi. Legend says YanDi could speak after 3 days of his birth, could walk after the fifth day, and at only 3 years of age, he know the essense of agriculture.Through his life, he did many good things to the people, he directed the agriculture that no one was lack of food and cloth, in order to find cures to illness of man, he personally tasted many unknow wild vegetations, that it is said he poisoned himself 70 times in a single day. He also make musical instruments, and teach the people how to follow proprieties. His clan originally came from the south of ShannXi, along the yellow river, his clan spread towards the east, where evetually clashed with HuangDi. YanDi and HuangDi fought at BanQuan, with HuangDi's victory and the forming of Yan-Huang alliance, the HuaXia is born, thats why Han Chinese today still call themselves "Scions of the Yellow and Fire emperors".
Besides the ancestors of Xia, Shang, Zhou dynasties were descendants of the Yellow emperor, many their vassel states and clans were also founded by YanDi's descendants, for that war Confucius despises between the Lu and Qi, Lu was founded by Ji clan, which was descendant of the Yellow emperor, whereas the Qi was by Jiang clan, the descendant of the Fire emperor.
Edited by The Charioteer