272 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



UPAESTHESIUS LEEANUS Rathbun 



Plate 112 



Lipaesthesius leeanus Rathbun, Proc. U. S. Nat. Mus., vol. 21, 1898, p. 585, pi. 



42, figs. 4 and 5 (type-locality, southern part of Gulf of California, 10 



fathoms; type. Cat. No. 21581, U.S.N.M.). 

 Medaeus rugosus Boone, ^oologica, vol. 8, 1927, p. 201, text-fig. 70 (type-loca'ity, 



off Gardner Bay, Hood Island, Galapagos Islands; type in Mus. N. Y. Zool. 



Soc). 



Diagnosis. — Basal antennal article terminating at prolongation of 

 front. Surface of carapace and appendages covered with pearly- 

 granules which form a more or 

 less reticulating pattern. 



Description. — Mesogastric and 

 cardiac regions depressed; proto- 

 gastric region forming an elevated 

 protuberance; a sinailar but 

 smaller protuberance at middle of 

 branchial region, and in front of 

 it, two tubercles. Hepatic region 

 inclined strongly toward the ver- 

 tical. Antero-lateral margin sub- 

 acute, with about four distant 

 tubercles above the edge. Sur- 

 face covered with coarse, bead 

 granules arranged to form a net- 

 work or an eroded surface ; gastric 

 sutures smooth. Front strongly 

 deflexed, thin, emarginate, a short 

 closed median fissure; lobes oblique, sinuous, bent down at outer angles 

 to meet basal antennal article. Upper inner angle of orbit fused 

 with the front and without tooth. 



The basal antennal article is broad behind, obliquely placed, its 

 distal surface (where the next article is commonly attached) is fixed 

 against the downward prolongation of the front. In the type- 

 specimen, the inner lower angle of the orbit also joins the front, 

 closing the orbit. The antenna, however, is not without a flagellum, 

 as at first supposed. By rotating the eyestalk a short flagellum of a 

 few articles (tip broken off) was disclosed; its attachment is entirely 

 concealed as it proceeds from the upper surface of the basal article, 

 bordering the Hning of the orbit.^^ In a smaller male from the type- 

 locality, the union of the front with the orbital angle is very slight, 

 whereas in a small male from Maria Madre, there is no union of front 

 with orbit and the outer angle of the basal article of the antenna lies 

 in the orbital hiatus. The attachment of the movable part of the 

 antenna to the basis is concealed but is not so remote from the orbital 



Figure 43.— Lipaesthesius leeanus, 

 holotype, carapace 11.4 mm. wide. 

 VIEW. b. Dorsal view 



MALE, 



Front 



M This discovery was not made until the validity of "Medaeus rugonu" was investigated. 



