The costume represented in these photos is dated from the time of the third Punic War until the period of Gaius Marius reforms. I specify "period" because it is more an evolution in time that was formalized in some way by Marius rather than a sudden event.
The Hastatus constitute the first battle line of the legion. Young and fiery at heart they have to prove themselves. Established in the fourth century BC as part of Camillan reforms, they are the second-class soldiers, the poorest after the velites. In fact it was more the younger men rather than just the poorer, though most men of their age were relatively poor.
Our Hastatus wear on its head an Etrusco-Italic style bronze helmet that covers his skull very well. On top Polybius tells us that in order to increase their stature, they carry a crest of black or red feathers 3 cubits long.
His body is protected by a bronze plate called cardiophylax and is doubled in the back. It is a protection typically Italic light enough, fast to manufacture and therefore less expensive than chain mail. The young legionary will have to compensate the lack of protection offered by its cardiophylax by increased combat speed.
At its height a simple leather belt which supports its gladius, the Hispanic sword worn on the right since the Iberian wars.
He holds in his right hand two pila as throwing weapon, one light and one heavy. This doubled their effectiveness, not only as a strong leading edge to their cohort, but also as a stand-alone missile troop.
His left hand rests on the great republican shield that serves both for his protection and as an offensive weapon.
His feet are shod with perones (photo above) which are small closed laced up boots from pastoral origin. They will equip the Roman soldiers until their replacement by caligae (pictured right) strong peasant studded sandal better suited for long distance walk imposed by campaigns increasingly distant from Rome.
Polybius describes this class of soldiers as often bearing a single greave on the left leg, the one that is the most exposed in combat.
From the middle of the second Punic War on, he is armed for close combat the terrible gladius Hispaniensis type of sword that has replaced the Xiphos type sword used before. This sword was of a higher quality and known for causing horrific injuries according to ancient writers.
This photo shows that the Etruscan-Italic helmet, although simple in design, perfectly protects the head of our young Hastatus.