Isla's gifts were first shown in his Triunfo del amor y de la lealtad: Dia Grande de Navarra, a satirical description of the ceremonies at Pamplona in honour of Ferdinand VI.'s accession; its sly humour so far escaped the victims that they thanked the writer for his appreciation of their local efforts, but the true significance of the work was discovered shortly afterwards, and the protests were so violent that Isla was transferred by his superiors to another district.
The accompanying dia grams (figs.
Of the families Belo- stomatidae, Nepidae, Corixidae and Hydrometridae have a pulsating sac at each knee-joint to assist the flow of blood through the legs, while in dragon-flies and locusts (Acridazdae) there is a ventral pulsating dia phragm, which forms the roof of a sinus enclosing the nerve-cords.
Excavations, commenced in the 16th century and continued to the 19th, in the grove of the Dea Dia about 5 m.