In the upper left part it shows the figure of a flying insect well known for its industriousness: the bee, which symbolizes the work and active vocation of the Las Tunas people. This area is blue in color like the sea that surrounds us, the sky that protects us and three stripes of the National Flag of Cuba.
In the upper right part of the shield from Las Tunas is the image of a key, which represents the geographical position that Las Tunas occupies on the Cuban map, between the legendary Camagüey and the indomitable East. The barracks has a red background, like the triangle of the Enseña patria, in remembrance of the blood shed by the independence fighters in their bloody struggles for freedom.
The lower left part includes the image of a ceiba tree, the tree that sheltered those who fought for the independence of the country and around which the city was founded. This symbol of the native flora is inserted within a context of green tones, very recurrent in the rural landscape of the territory.In the lower right part of the shield of Las Tunas appear the ruins of the barracks of the 28 columns, former military bastion of Spanish colonialism in the city, (today a Primary School), which symbolizes the defeat of the Iberian hosts in the area. 
There is also an image of a woman, whose participation in our struggles is recognized by historiography. In addition, a bonfire, a symbol of the times the city was burned in a holocaust for freedom. The plant called prickly pear is a suggestion as to why this region is called that.
Sources: https://www.ecured.cu/Archivo:Escudo_de_la_ciudad.jpg

https://www.ecured.cu/Archivo:Escudo_de_la_ciudad.jpg
Own work
RamphysDistrict