142 



BULLETIN 54, UNITED 8TATES NATIONAL MUSEUM, 



Fig. 12'2.— Exocorallana mexicana. a. Mandible 



•: 51^. h. Second pleopod of male ■: 27|. 



EXOCORALLANA MEXICANA, new species. 



Bod\^ ovate, a little more than twice a,s long as wide, 8 mm., 7 mm. 



Head wider than long-, about twice as wide as long, 1 mm., 2 mm., 



with the anterior margin widel}' rounded and the posterior margin 



straight. Eyes large, composed of numerous ocelli, and separated in 



front by a distance equal to the 

 length of one eye. Two small 

 tu))ercles are situated about the 

 middle of the head between the 

 eyes, one on either side of the 

 median line. The first pair of 

 antemue have the peduncle com- 

 posed of only two articles, the 

 first article being nearly twice 

 as long as the second. The 

 flagellum. which is composed 

 of ten or eleven articles, ex- 

 tends to the posterior margin 

 of the head or to the end of the foui'th article of the peduncle of the 

 second pair of antennae The second pair of antennte have the tirst 

 three articles of the peduncle short, the second one being the shortest; 

 the fourth and fifth are long and subequal, 

 each being about as long as the tirst three 

 articles taken together. The flagellum is 

 composed of about twenty-live articles, 

 and extends to the middle of the tifth tho- 

 racic segment. The frontal lamina is nar- 

 row, elongate, and has the anterior end 

 rounded. The clypeus is short and wide. 

 The mandible is distinctly tridentate, the 

 posterior tooth being the most elongate. 

 The first segment of the thorax is al)out 

 one and one-half times longer than any of 

 the three following segments, which are 

 subecjual. The fifth, sixth, and seventh 

 segments are subequal and shorter than 

 the^Dreceding segments, and each is fur- 

 nished with a double or single transverse 



row of small tubercles close to the posterior margin. The anterior 

 segments are sometimes furnished with a rather indistinct row of tuber- 

 cles on the posterior ma»gin. The epimera are distinct on all the 

 segments with the exception of the first; the first two are rounded 

 posteriorly, the last four have the outer posterior angle gradually more 

 acutely produced. 



LVOtORVI L\N \ MVWrXSA. 



Male x o 



