Lewis & Short

lactes, ium (in sing. lactis, is, only, acc. to Prisc. p. 686, erroneously on account of lactis agninas), f. [root lag-; Gr. λαγαρός; cf. Lat. languidus, laxus], the intestines; esp. the smaller intestines, chitterlings (anteclass. and post-Aug.): ab hoc ventriculo lactes in homine et ove, per quas labitur cibus: in ceteris hillae, Plin. 11, 37, 79, § 200: ita cibi vocivitate venio lassis lactibus, i. e. empty, famished, Plaut. Curc. 2, 3, 40: pulmone et lactibus unctis, Pers. 2, 30.
Prov.: adligare canem fugitivom agninis lactibus, said of the employment of a trifling remedy for a great evil, Plaut. Ps. 1, 3, 85.