REVISION MALACOSOMA HUBNER IN NORTH AMERICA 39 



Female Terminalia 



As in the males, the terminalia are covered by numerous scales and 

 setae which usually must be removed before the diagnostic structures 

 can be clearly seen. The external terminalia of female Malacosoma are 

 basically the same as the terminalia of other higher Lepidoptera, 

 consisting of an external copulatory opening to tlie bursa copulatrix on 

 the eighth sternite (the ostium), and of the ovipositor. The ostium is 

 surrounded by an area which may be heavily sclerotized, only par- 

 tially sclerotized, or nonsclerotized. The term "genital plate" is applied 

 to this area (figs. 83, 90, 95, and 102). The degree of sclerotization, 

 the shape, and the position of the ostium in the genital plate have 

 some systematic value. The internal genital structures are nonpig- 

 mented and membranous, and they have no known systematic value. 

 See Snodgrass (1938) for an illustration and description of the internal 

 reproductive system. 



The ovipositor lobes (figs. 81-104 except 83, 90, 95, and 102) are 

 blunt, each with dorsal and ventral sublobes (fig. 100) that have 

 considerable systematic value. The anterior-lateral area of each lobe 

 is lightly sclerotized. Extending anteriorly from this area is a long 

 apodeme on each side that has little systematic usefulness. Posteriorly, 

 the ovipositor lobes are somewhat wrinkled and covered with numerous 

 setae. The conformation of the lobes around the c%^ pore and anus 

 (figs. 82, 85, 87, 89, 92, and 94) is sometimes helpful in identification. 



Larvae 



Chaetotaxy 



Although Dyar (1895b) numbered and noted the arrangement of the 

 "warts" which bear the primary setae on the first instar larva, as far as 

 is known, no attempt has been made to separate the larvae of Malaco- 

 soma by characters other than color and color pattern. This is under- 

 standable for two reasons. First, the color pattern is quite sufficient to 

 distinguish some species in the later instars, and second, the large num- 

 bers of secondary setae superficially obscure the primary groups of 

 setae. 



Examination of first instar larvae has revealed groups of setae unob- 

 scured by the numerous secondary setae present in the later instars. 



