Dr. A. S. Packard on neiv North-American Phyllopoda. 333 



Apodid^. 



The known species of Apus may be for convenience divided 

 into three sections, characterized in part by the length of the 

 shield, or carapace, the highest forms having the shortest cara- 

 pace ; those with the longest shields, as the European Apus 

 cancriformis^ approximating in this and other characters to the 

 genus Lepidurus. 



Section a comprises Apus longicaudatus, Lucasanus^ New- 

 herryi^ and probably domingensis. 



Section h comprises Apus cequalis and Guildingii. 



Section c comprises A. cancriformis and Mmalayanus. 



Apus longicaudatus^ Leconte, Ann. N. Y. Lyceum. — Prof. 

 Dana^s type specimen, which is now very imperfect, was labelled 

 " Rocky Mountains, near Long's Peak." Four specimens 

 from "Texas, J. H. Clark, No. 3." Three specimens from 

 " pools near Yellowstone river. Dr. Hayden, No. 6." Mus. 

 Chicago Acad. Both sexes occurred, the females having eggs. 

 James's A. obtusatus (Long's Expedition) is probably this spe- 

 cies. A. numidicus, Lucas, from Algeria, in the form of the 

 carapace seems to be allied to A. longicaudatus. 



Apus LucasanuSjja.. sp. — ^q\.o&q[j ?W\Q,diio A. longicaudatus. 

 Theirontal doublure rather longer than in longicaudatus, and 

 hypostoma a little smaller ; maxillipeds shorter and smaller, 

 and telson longer than in the preceding species, with three 

 median spines above ; anal stylets less spiny. Number of 

 segments behind posterior edge of shield 33 ; number behind 

 the last pair of gills (including telson) 13. Length of body 

 (excluding caudal stylets) "94, of carapace along the middle 

 •37 ; total length of carapace "48 ; length of tergal carina "24 ; 

 distance from anterior end of carina to front edge of carapace 

 •16 ; length of caudal stylets •ST, being a little over half the 

 length of body ; breadth of shield '40 inch. 



Six specimens in a bottle labelled " Kansas, No. 5," and con- 

 taining thirteen ? A. cequalis. Mus. Chicago Acad. They 

 cannot be distinguished from St. Lucas specimens. 



$ . Carapace longer than in $ , and caudal stylets not so 

 heavily spined. Number of segments behind posterior edge of 

 shield 29 ; number behind last pair of feet 11. Length of body 

 80, of carapace along the middle "30 ; total length of carapace 

 •40 ; length of tergal carina "25 ; distance from front end of 

 carina to front edge of carapace '16 (stylet broken) ; diameter 

 of egg-sacs ^09 inch. 



One specimen from " Cape St. Lucas, John Xanthus, No. 4." 

 Mus. Chicago Acad. 



■^^^^¥S:P^J'VKHJy- ^V-) ? • — "^^^^ fine species differs from 



