A number of X-ray or EMS-induced mutants of Drosophila hydei are described, which represent a type not previously known for this species. Our preliminary data suggest that they are parallel mutants to the Minute mutants of D. melanogaster: Heterozygous individuals have short and slender bristles, smaller body size, and show a delay in larval development. Homozygotes are lethal. Mutants were mapped to all chromosomes except chromosome 6 (dot), and the examination of salivary gland chromosomes revealed the presence of small deficiencies in several of the mutants.

On the other hand, secondary phenotypic effects as described for many Minutes in D. melanogaster are scarce. Nor did any of the D. hydei Minutes tested, increase the rate of X-ray-induced somatic crossing-over in the chromosome.

These mutants may offer a useful tool in both developmental and genetic studies in this species owing to their effects on larval development and their distribution in the genome.