144 UNITED STATES NATIONAL MUSEUM BULLETIN 276 



black area on each segment. Primary and numerous secondary dorsal 

 setae orange. Primary and secondary lateral setae white; secondary 

 setae numerous and somewhat tufted anteriorly on each segment 

 around setal group L2 on many specimens. 



LARVAL DIAGNOSIS. — Larvae intergrade to the north with c. 

 californicum from which they are most easily separated by the white 

 lateral setae and the bluish lateral areas which emphasize the white 

 setae. Larvae of c. californicum have orange lateral setae and black 

 lateral areas. 



EGG MASSES, TENTS, AND COCOONS.— The same as de- 

 scribed for c. californicum (page 141). 



FOOD PLANTS. — Egg masses were found on the following trees 

 and shrubs : Ceanothus thyrsijlorus, Ceanothus incanus, plum, prune, apricot, 

 apple, Salix sp., and Qiiercus agrifolia. It was collected on Quercus 

 agrifolia only once near Santa Cruz. Quercus agrifolia does not appear to 

 be a preferred host, although there is plenty of it available. The native 

 hosts were probably Ceanothus spp. and Salix spp. In this respect it 

 differs from c. californicum which is often found on Quercus agrifolia, a 

 point that will be discussed below under "comments." 



TYPE. — Lectotype, here designated, a male in the United States 

 National Museum. USNM Type No. 34896. Size: The type is a 

 semiadult in that it is a specimen which did not wholly emerge from 

 pupal case; only the antennae, unexpanded wings, and the top of the 

 head are visible. This no doubt accounts for Dyar's statement in the 

 original description saying, "My specimens are too poor to enable me 

 to give characters to separate the moths from C. calif ornica, which they 

 much resemble, but the larvae are abundantly distinct." Data: 

 type; ambisimilis Dyar; BB345; male genitalia No. 1 — on slide, 6 July 

 1933, C. H. [Carl Heinrich's initials]; Lectotype, Malacosoma ambisimile 

 (Dyar), male, F. W. Stehr 1963. The number "BB345" refers to Dyar's 

 brown notebook number 345 which contains his field notes. This 

 notebook indicates he collected them on apple and cherry at Watson- 

 ville, California, on 16 April 1892. It also contains about two pages of 

 larval descriptions of various instars. Genitalia mounted on a slide 

 bearing the following labels: Malacosoma ambisimilis Dyar, "BB-345," 

 TYPE, male genitalia, slide, 6 July 33, C. H. No. 1. 



TYPE LOCALITY.— Watsonville, California. 



PARALECTOTYPES.— A single female semiadult, but with only 

 the unexpanded wings and the tip of the abdomen showing. USNM. 



DISTRIBUTION (figs. 3 and 6).— On the southwest side of San 

 Francisco Bay it extends north to the Los Altos area where it inter- 

 grades with c. californicum east of the ridgeline of the Santa Cruz 

 Mountains. On the west side of the ridge of the Santa Cruz Mountains 



