468 PROCEEDINGS OF THE NATIONAL, MUSEUM vol.88 



Specimens labeled A. m£galops var. spinosus in the Museum are 

 not different from the regular species except that they are lighter 

 in color; hence the spinous under portion of the body is more con- 

 spicuous. Color seems too variable to use in establishing differences. 

 A. varians, recently described by Bere from females, is similar to 

 A. megalops except for the great variation in the size of the carapace. 

 Four specimens from the Bass Biological Laboratory show these 

 gradations well. 



The male of A. latus Smith (1873) has never been reported be- 

 cause it is identical with funduli Kr0yer (1864) so far as the available 

 specimens are concerned. 



A. maculosus has been redescribed because no specimen was found 

 to match the original description. The species was figured as hav- 

 ing the characters of americcmus. It was established on the basis of 

 color. However, there are actual specimens of a species that may 

 be considered as representing maculosus. As the types in the Na- 

 tional Museum proved to be aniericanuSy it is necessary to designate 

 new types for maculosus. 



A.piperatus 'Wilson (1920a) is identical with males of A.fiavescens 

 Wilson (1916), as described by Mueller (1936) and as collected by 

 myself in Florida. A. paulensis is apparently the same as A. salminei, 

 although no specimens of the latter are at hand. 



Specimens of A. japonicus collected by Dr. Pearse in Japan and 

 those sent me from that country proved to be identical with A. 

 trilineatus, thus invalidating another species. There are, therefore, 

 21 North American, 2 South American, 2 Siamese, and 1 African 

 species available for study in the Museum. These include all the 

 North American species except some undescribed ones that Dr. Wilson 

 has at the present time. 



It is suggested that the key be used in combination with the figures 

 of the respiratory areas in order that identification be accurate. 

 The other figures may also be used to advantage, especially those of 

 the male accessory copulatory organs. 



DEVELOPMENT 



Larval stages have been described for A. foliaceus, a European 

 species, and for A. funduli. A. m^galops^ A. americanus., A. macidosus, 

 A. catostomi., and A. stizostethii from this country. More recently 

 T. Tokioka (1936b) has given a very good account of A. japonicus y 

 which is also common in this country. JSIartin (1932) described the 

 development of the proboscis from the early embryos of A. viridis 

 in England. A generalized description of larval development is 

 somewhat as follows: 



