Autoradiographic studies using 3H uridine in the salivary glands of three bugs, Lethocerus indicus, Laccotrephes rubra and Antilochus coqueberti show that the nuclei play an important role in contributing RNA. The labelled materials are seen to move into the lumen from the epithelia. RNA shows a tendency to accumulate in the lumen with ascending incubation periods. This behaviour in conjunction with its nucleolar genesis indicates its nature as rRNA. It is also believed that RNA might conjugate with some of the protein available in the lumen to produce RNP.

Autoradiographic observations using (3H) glycine in the salivary glands of Lethocerus indicus, Laccotrephes rubra and Antilochus coqueberti indicated synthetic activity being performed by the glandular epithelia in all the bugs at short incubation periods. Long incubation periods showed that the site of heavy labelling shifts from outside inwards, with progressive incubation timings, namely from the basal borders and eventually into the lumen. This shifting of the labelling from outside inwards suggests the glandular epithelium is also capable of transporting some of the haemolymph proteins into the gland in all the species and thus indicating heterosynthetic origin of saliva.