SPUR PATTERNS ON THE TIBIA AND FEMUR IN THE BENT SPUR MUTANT OF THE GERMAN-COCKROACH (DICTYOPTERA, BLATTELLIDAE)

The bent-spur (bs) mutant of the German cockroach, Blattella germanica (L.), has sharply bent spurs on the tibia and femur of the three pair s of legs. Spur patterns of this mutant are identical with those of wi ld type; thus every spur can be named by a row-and-level method used i n wild type. Mutant spurs are not bent in the first instar, but a few of them become bent in the second instar. On the tibia, many spurs bec ome bent in the third instar, and the percentage of bent spurs becomes highest in the adult. The percentage of bent spurs is lower on the fe mur than on the tibia from the third instar to the adult. A few double -bent spurs appear both on the tibia and femur in the third instar. On the tibia, the percentage of double-bent spurs gradually increases to the adult. On the femur, however, double-bent spurs are rare througho ut development. Detailed analysis shows that spurs are always straight in the stadium in which they appear for the first time. Some of them become bent but not double-bent in the next stadium and then become do uble-bent in the following stadium.