The gall-forming aphid <em>Tetraneura fusiformis</em> is recorded for the first time for Northern South America. Its identity is clarified, and descriptions of this species and that of <em>T. nigriabdominalis</em>, with which it is commonly confused, are offered. The association of this sap sucking insect with the ant <em>Linepithema angulatum</em> (Hymenoptera: Formicidae) is recorded for the first time as well.