Heteroptera have piercing and sucking type of mouth parts. They used to suck plant sap by inserting it’s stylet on the host surface. When the insect start inserting it’s stylet on the host surface (eg- bean, tomato, eggplant), salivary secretion occurs and it starts depositing by producing a ring like structure. A salivary sheath also protrudes from that ring . This whole structure is called Feeding puncture. Different bugs produce different types of feeding punctures depending on the length of the stylet and amount of salivary deposition.
A thin transverse section of bean was made and put it on a clean glass slide. Then the specimen was covered with transparent cellotape and observed under the foldscope and few photos were captured.