140 UNITED STATES NATIONAL MUSEUM BULLETIN 276 



ADULT DIAGNOSIS. — Indistinguishable as adults from adjoining 

 populations of californicum to the north with which they intergrade; 

 indistinguishable as adults from M. californicum ambisimile to the south, 

 except that yellowish males similar to figure 1 76 from the area around 

 San Francisco Bay are probably californicum californicum since very few 

 yellowish male californicum ambisimile have been seen to date. 



Males are not likely to be confused with the other two species found 

 in the same area {disstria and constrictum), but see the diagnosis for them 

 for characters which will positively identify them (pages 86 and 94). 

 Light females with dark lines may be confused with female disstria, 

 but disstria can always be identified by the characters given for it (page 

 87). Locality information is essential to identify adults to subspecies, 

 since californicum californicum is largely recognized on larval differences. 



MATURE LARVAE (figs. 352, 353).— Head black, sometimes 

 lightly mottled with blue, sparsely covered with fine yellow-orange 

 setae. Middorsal area of body black, almost invariably without a 

 stripe, but rarely with a faint whitish line on some segments. Addorsal 

 area black with weak, longitudinal, irregular, wavy orange lines which 

 are totally obscured in many specimens. The orange lines are more 

 distinct in preserved specimens and in early instars. Subdorsal area 

 black. Posterior subdorsal spot sometimes present as a smaller blue- 

 white dot; rarely both spots are absent and larva will be entirely black; 

 occasionally both spots will be quite distinct, in which case the amount 

 of black is reduced, the addorsal orange lines are more prominent, and 

 the vertical black bar between setal groups Dl and SD becomes visible. 

 Subdorsal line usually absent, but occasionally visible as a broken 

 yellow-orange line. Supraspiracular and subspiracular areas black, 

 occasionally streaked with orange. Ventral area black, sometimes 

 mottled with gray-white, especially on those specimens where other 

 markings are most pronounced. Primary and numerous secondary 

 dorsal setae orange. Primary and secondary lateral setae also orange; 

 secondary setae quite numerous and sometimes slightly tufted anteriorly 

 on each segment around setal group L2. Rarely, some larvae may have 

 yellowish-white lateral setae. 



LARVAL DIAGNOSIS. — M. californicum californicum larvae are 

 the only ones found in the San Francisco Bay area which are almost 

 entirely black with little or no middorsal or addorsal markings, and 

 which have orange primary and secondary dorsal and lateral setae. 

 They intergrade to the north with those larvae of M. californicum in 

 which the markings are more distinct so that some kind of pattern is 

 evident (figs. 358-360), and in which the lateral setae may be orange, 

 or more rarely white (especially in the Mendocino-Trinity population 

 as in figs. 361-363). To the south they intergrade (figs. 356 and 357) 



