124 



W'LLKTIN OF THE BUREAU OK FISHERIES. 



Found upon the common sucker, Catostomus, and the chubsucker, Erimyzon, in both salt and 

 brackish water; deposits its eggs the middle or the last of May (May20-June 5). Eggs of medium 

 size, arranged in short rows, gathered into small patches containing 6 or 8 to 12 eggs; rows not parallel; 

 eggs placed end to end and covered with a jelly envelope, the surface of which is raised into long 

 rows of club-shaped papillae, which are often twisted spirally. Eggs hatch in 30-35 days; emerging 

 larva light grayish in color, unpigmented, not very transparent, totally unlike the adult; carapace 

 elliptical, longer than wide, but scarcely reaching to the center of the second (the first free) thoracic 



Newly hatched larva of Argulue catostomi, 325. a. a., Anterior antennae; p. a., 

 posterior antennae; a. hi., anterior maxillipeds; p. m. t posterior iiiiixillipi-.lv. 

 in. p., mandibular palp; s. /.. swimming leg. 



segment, leaving a very shallow posterior sinus; free thoracic segments rapidly diminishing in size. 

 Abdomen narrower than last thoracic segment, elongate-triangular in shape, cut nearly to the 

 center; anal sinus triangular; each lobe somewhat constricted at the base; papillae terminal and 

 ending in two very long setae. Skin glands scattered about promiscuously, scarcely noticeable. Larva 

 furnished with a temporary rowing apparatus, consisting of the greatly enlarged second antenna' 

 and a pair of transitory mandibular palps, the former terminating in four long plumose set;e and 

 a tilth much shorter, noiiplu se one, like the thumb and lingers of a hand; the latter with .". 



