The midgut of D. peruvianus is divided into three regions (V₁ – V₃). Absorption of water and glucose occur at V₁. Protein digestion is carried out by a cysteine proteinase at V₂, where K^{+ -} dependent amino acid absorption also occurs. V₃ resembles V₂, but is less important and V₄ is a linking region (Insect Biochem. Molc. Biol., vol. 24; 493-505, 1994). The midgut cells have a second plasma membrane (perimicrovillar membrane) ensheathing the microvillar  membrane. The aim of this work is to describe the molecular mechanisms underlying physiological phenomena in this unique tissue. For this a cDNA library was prepared from midgut RNA. This library was randomly sequenced. By now 480 ESTs were generated from whitch 63 ESTs were assembled into 25 contigs. Single sequences and contigs were BLAST analyzed with the aid of the NCBI non-redundant data base. Among the homologous sequences found the following are more relevant to our aim: porins, cysteine proteinase, aminopeptidase, b-glucosidase, Ca²⁺/H⁺ cation transport protein, ABC transporter, ATPase component of ABC-type transport system and transmembrane amino acid transporter protein. Cloning and expression of cDNAs related with absorption of amino acid will be useful for elucidation of this mechanism.