652 PROCEEDINOS OF THE NATIONAL MUSEUM. vol.47. 



body. The posterior opening of the lorica is large and the bulbous 

 foot projects some distance through it. The toe is half the length of 

 the body, slightly recurved at the base and straight posteriorly; it 

 is accompanied by two minute substyles. The dorsal antenna is on 

 the striated area, opposite the constriction separating the head 

 sheath from the body; the left lateral antenna is on the posterior 

 third of the body; the right antenna has not been observed. 



Total length, 182 /x; length of body, 122 /x, depth, 45 //; length of 

 toe, 60 /x. 



Type.— Cat. No. 16587, U.S.N.M., is from a pond at Bolrio (7); the 

 species also occi^fs in a stagnant pool at Empire (4) and Rio Tiinidad, 

 at Escoval (11); only a few specimens were found in each of the 

 collections mentioned. 



This species has some resemblance to Tnchocerca pusiUa (Jennings) ; 

 the body is, however, much more slender. 



TRICHOCERCA RATTUS (MUller). 



Rattulus rattles Jennings, Bull. U. S. Fish Comm., vol. 22, 1903, p. 333, pi. 11, 

 figs. 100, 101. 



From Rio Grande Reservoir (5), rare; Rio Trinidad, at Escoval 

 (11), few; pond north of fill work at Miraflores, back water of Rio 

 CamitiUo (12), rare. 



DIURELLA BRACHYURA (Gosse). 



In a creek flowing into Camacho Reservoir (3), few; pond west of 

 Rio Chagres, at Bohio (7), rare; Rio Trinidad, at Escoval (11), few. 



DIURELLA WEBERI Jennings. 



In a creek flowing into Camacho Reservoir (3), few; Rio Grande, 

 (6), rare. 



DIURELLA VOLUTA Murray. 



Owing to an insufficiency of material, the measurements were not 

 given by Miu-ray in the original description. The length of the 

 lorica is 135 fi; length of toes, from 36 to 42 n; depth of body, 54 //; 

 width of body over keel, 54 /z; of body alone, 45 /t. 



This species occurred in collections from Rio Grande Reservoir (5), 

 not common. 



DIURELLA STYLATA Eyferth. . 



From Rio Grande Reservoir (5), few; Carabali (Gorgona) Reser- 

 voir, common; Rio Ti-inidad, at Escoval (11), few; pond at Mira- 

 flores, back water of Rio CamitiUo (12), few. 



DIURELLA TIGRIS (MUller). 



From a creek flowing into Camacho Reservoir (3), common; Rio 

 Grande Reservoir (5), few; Rio Grande (6), few; pond east of canal 

 at Empire (8), rare. 



