REVISION MALACOSOMA HUBNER IN NORTH AMERICA 185 



of i. aztecum because of the variability found in the spumaline of i. 

 incurvum (page 172). 



TENTS. — The only tent examined to date is a poor one in the United 

 States National Museum, but it is large, and similar to those constructed 

 by other populations of M. incurvum, and by M. calif ornicum and M. 

 americanum. 



COCOONS. — Only a few cocoons have been examined. They are 

 fairly tightly constructed, with little or no outer envelope of silk, and 

 are dusted with a whitish powder. Ancona (1930) reported yellowish 

 powder on the cocoons he examined. 



FOOD PLANTS. — It has been collected from Salix lasiolepis, Prunus 

 capulis, willow, trembling aspen and ocean spray {Holodiscus sp.). 

 Ancona (1930) reported it from Salix mexicana and Salix bomplanidiana. 

 In this respect /. aztecum is quite similar to M. incurvum irwurvum which 

 commonly occurs on both Salix and Prunus in southern Arizona, in 

 addition to Cottonwood. The records from willow, trembling aspen, 

 and ocean spray are from an area 6-10 miles W. of El Salto, Durango. 



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

 National Museum. USNM Type No. 33657. Size: 27 mm. wing- 

 spread. Data: Clisiocampa azteca Neumoegen, male, Type; ty^picum 

 specimen; City-Mexico; Lectotype, Malacosoma aztecum (Neumoegen), 

 male, F. W. Stehr 1963. Genitalia in microvial labeled: Lectotype, 

 Malacosoma aztecum (Neumoegen), male genitalia, F. W. Stehr 1963. 



TYPE LOCALITY.— Mexico City, D. F., Mexico. 



PARALECTOTYPES.— One male, two females in the USNM. 



DISTRIBUTION. — It has been reported from several states in 

 Mexico, including Tlaxcala, Puebla, Chihuahua, Durango, Vera Cruz, 

 and the Distrito Federal. It undoubtedly occurs in many other places 

 in the central Mexican plateau, but it remains to be seen whether some 

 form of M. calif ornicum will be found in the same areas, and how much 

 intergradation or isolation is present. 



COMMENTS. — In nearly every respect (hosts, egg masses, larvae, 

 adults) aztecum is more similar to M. incurvum than to any known 

 populations of M. calif ornicum. Despite the great similarity to incurvum, 

 the available egg masses, larvae, and adult males of aztecum differ from 

 the majority of the egg masses, larvae, and adult male incurvum incurvum 

 found in Arizona. Some populations of irwurvum incurvum in southern 

 Arizona, however, contain a variable percentage of individuals which 

 are quite similar to corresponding life stages of aztecum. These include: 

 ( 1 ) The egg masses which are covered with dark spumaline, similar to 

 figure 1 1 4 (most egg masses of i. incurvum are covered with whitish 

 spumaline similar to fig. 117). (2) The darker, blacker larvae similar 

 to figures 391 and 394 (most larvae of/, incurvum are lighter and bluer 



