The key description and illustrations of mouthparts, ocelli, and terminal abdominal segments by Bovinq & Craighead (1931) have been the only information on the larval stages of the genus Hemipeplus Latreille, except for the observation by van Emden (1942) that individuals of the genus would not key properly in Boving & Craighead's key. Their example was of an undescribed species from Cuba. The semidiagrammatic illustrations make it difficult to identify the species illustrated, although it may be H. marginipennis (LeConte). This paper is based on larvae collected by the authors, in each case associated with adults. From the family diagnosis of larval Mycteridae (Crowson & Viedma 1964). Hemipeplus larvae differ noticeably in the form of the sensorium, which Crowson & Viedma describe as “very short, dome-shaped”; in Hemipeplus it is elongate and conical. From the larva of Mycterus (described by Crowson & Viedma 1964) those of Hemipeplus also differ in having five ocelli on each side (cf. two), mala with an uncus and medial pit (cf. without uncus or medial pit), mola ridged (cf. not ridged), cardines not divided (cf. distinctly divided, labial palpi with only one distinct palpomere (cf. with two palpomeres), abdominal asperities absent (cf. asperities present), and different form of spiracle (compare fig. 13 with fig. 4 in Crowson & Viedma 1964). Larvae of Hemipeplus are more similar to that of Eurypus muelleri Seldlitz (described by Costa & Vanin 1977) than to that of Mycterus. As in Hemipeplus, Eurypus larvae possess five ocelli arranged in rows of three and two on each side; two pairs of tubercles at posterior margin of abdominal sternite IX; mala with an uncus, and cardines divided. Hemipeplus larvae differ from those of Mycterus most notably in the form of abdominal tergite IX (see Costa & Vanin 1977:fig. 2 ) . The uncus is located on the mesal margin of the mala in Hemipeplus, whereas it is located on the ventral aspect of the mala in Eurypus.