REVISION MALACOSOMA HUBNER IN NORTH AMERICA 101 



La Canada, Los Angeles Co., Calif., are evidently from the transi- 

 tion zone between M. constrictum constrictum and M. constrictiim austrinum 

 since about half of them had white lateral setae and the other half 

 orange or yellowish lateral setae. The dorsal blue and black pattern 

 was also more distinct than typical constrictum austrinum in which it is 

 more obscured by black. Not enough larval collections have been 

 made to plot the northern boundary accurately, but on the basis of 

 the preserved larvae that are available it can arbitrarily be set along 

 a line drawn from Indio, Riverside County, Calif, along the southern 

 base of the San Bernardino and San Gabriel Mountains. A definite 

 boundary can rarely be set for any continental subspecies, and this 

 is no exception since there appears to be a transition zone on the south 

 slopes of the San Bernardino and San Gabriel Mountains which may 

 extend westw^ard to Santa Barbara or even farther. Southward, the 

 distribution probably extends as far into Baja California as oaks 

 grow, but no specimens are recorded from there to date. The southern- 

 most record is Jacumba, San Diego County, which is adjacent to the 

 Mexican border. 



ECONOMIC IMPORTANCE.— In 1960 it was causing virtually 

 complete defoliation of Q_. dumosa and other oaks in the vicinity of 

 Guatay and Santa Ysabel, San Diego County, Calif. 



Specimens Examined. — 273 (Museum specimens — 90 males, 21 females, 3 

 larvae; reared specimens — 90 males, 69 females, plus numerous larvae and egg 

 masses). See Appendix I for collections made during this stvidy (page 257). 



Paratypes. — 23 last instar larvae, 90 males, 69 females, 30 egg masses, 

 one 1st instar molting tent, one 2d instar molting tent, and numerous 1st, 2d, 

 3d, and 4th instar larvae; all with the following data: Yi mi. E. Santa Ysabel, 

 San Diego Co., California, El. 3000 ft., Coll. No. 26, 2 April 1960, Host— 

 Quercus dumosa, F. W. Stehr. 



All paratypes are in the University of Minnesota Collection except the 

 following ones. Receiving 1 adult male and 1 adult female: Calif. Dept. of Agric, 

 Los Angeles Co. Mus., 111. Nat. Hist. Sur., Univ. of Idaho, Cornell Univ., 

 Ore. St. Univ., Carnegie Mus., and Charles Kimball. The Amer. Mus. Nat. 

 Hist, has 2 adult males, 2 adult females, and 1 egg mass; Mich. St. Univ. has 

 3 adult males, 3 adult females, 3 last instar larvae, and 2 egg masses; Univ. 

 Calif. Berkeley has 1 adult male, 1 adult female, and 1 last instar larva. Calif. 

 Acad. Sci. and Can. Nat. Coll. have 2 adult males, 2 adult females, 1 egg mass, 

 and 3 last instar larvae; U.S.N.M. has 4 adult males, 5 adult females, 3 egg 

 masses, and 3 last instar larvae. 



Other Specimens. — California: Avalon, Santa Catalina Island; Clare- 

 mont; Chula Vista; Fallbrook; Guatay; Holtville; Idyllwild, San Jacinto 

 Mountains; Jacumba; Julian; Live Oak Park (San Diego Co.); Los Angeles; 

 Mt. Lowe; Mt. Palomar State Park; Palm Springs; Palomar Mt.; Perris; 

 Rancho La Sierra, Arlington; Riverside; San Bernardino; San Diego; S. Felipe 



