508 PROCEEDINGS OF THE NATIONAL MUSEUM vol. ii4 



shaft with a continuous covering, and on the antennae of many 

 species is a complete ring of scales encircling each segment; about 

 90 percent of the smaller North American species of Acrolophus 

 have this complete ring of scales on each antennal segment. Seg- 

 ments clothed with scales in this manner are almost invariably of the 

 simple or globose t^^pe, although a striking exception is the completely 

 scaled but unipectinate antenna of A. texanellus, and in the subspecies 

 laticapitanus laticapitanus each antennal segment is furnished with 

 two complete rings of scales. Normally, this complete ring of scales 

 is wanting in the larger species and in those having complex types of 

 antennae; such species commonly have an incomplete ring in which 

 the scales extend partly onto the lateral surfaces of the antenna. 



The minute setae or sensory hairs are quite short in the simple 

 forms of antennae, although they tend to become elongated on those 

 segments bearing complex processes such as occur in the unipectinate 

 and bipectinate forms. The form and vestiture of the antennae are 

 consistent throughout the members of the cressoni-maculifer-cres- 

 centellus species group. Thus, in this case, the antenna assumes 

 potential generic value. Conversely, antennal forms are only of 

 subspecific value in the complex species, macrogaster and sinclairi. 



MALE GENITALIA 



Although there is still some disagreement among lepidopterists 

 as to the origins and limits of certain genital structures, especially 

 the tegumen, a rather generally accepted concept of their morphology 

 and homology throughout the different families now exists. Like- 

 wise, there has developed a group of terms widely used in the de- 

 scription of these structures. 



Pierce, in his pioneering works on British Noctuidae (1909) and 

 British Geometridae (1914), contributed much to the present knowl- 

 edge of the morphology and terminology of lepidopterous genitalia. 

 Although earlier workers, such as Buchanan-White, Gosse, Smith, 

 and Baker, had described and named some genital parts. Pierce was 

 probably the first to make a really detailed taxonomic study of the 

 entire male genital apparatus of many species and genera of moths. 

 He not only formulated a fairly complete set of names for these 

 structures but also was one of the first workers to stress the great 

 value of the aedeagus and its associated organs for the separation of 

 species. Busck and Heinrich (1921), in their paper on the systematic 

 importance of the male genitalia of Microlepidoptera, drew heavily 

 from Pierce's system of nomenclature and concept of morphology. 

 Subsequently, they applied their somewhat modified system in the 

 description of the genitalia of numerous new species of North Ameri- 

 can Microlepidoptera. Eyer (1924) published on the comparative 



