NO. 1443. CAVE SALAMANDERS— BANTA AND McATEE. 71 



There is evidence that even ji longer period may be passed in the 

 larval state by some individuals, and a longer period than the above 

 seems to be the rule for another member of the genus, Spclerpes hilin- 

 eatus. Concerning this species Wilder « says: "The larvJB * * * 

 hatch early and continue for a long time in the larval state, probabh' 

 2-3 3^ears, * * * The growth must be exceedingly slow and 

 dependent upon the fortune of the individual in securing prey. I 

 have caught all stages from 16-52 mm. at all seasons of the 3^ear, and 

 see no indication that those larvaj collected at any one time represent 

 one, two, or three years of definite growth." That slow develop- 

 ment is the rule in the genus is further shown by the life history of 

 Spelerpes ruher. Small and large larvae and recently transformed 

 individuals are commonly found together in the same spring. 



The small larvas of /S'. niacullcaudus are easily studied in their native 

 pools. The}' are most often found Ijnng quieth' on the bottom, in 

 their position and distribution reminding one of the johnn}' darters on 

 the creek bed. But the analogy can be carried no further; the dart- 

 ers are the incarnation of irritability and activit}^, while no mechan- 

 ical disturbance short of actual poking will cause these larv» to move. 

 "When captured at the first trial the feat seems easy, but when that 

 fails the larvae are elusive, and b}^ stirring up the sediment cloud the 

 water so that their motions are not easily followed. Their habit of 

 lying openly on the bottom is changed when they are confined in a 

 well-lighted vessel. Here the}^ seem ill at ease except when hiding 

 under some object on the bottom. When disturbed, the}' swim rap- 

 idly, but not for any length of time, as they soon seek the bottom and 

 nose about for a hiding place. This sensitiveness to light agrees with 

 their behavior in the cave. All larvae are very much more responsive 

 to light stimulus than the adults, the young larvje more so than the 

 older. The former always swim away from the source of light, while 

 the latter act in a more uncertain way, lowering and raising the head, 

 starting away but stopping immediately only to lower the head and 

 start in another direction. Alight held steadily upon them, how- 

 ever, will cause more decided action, a slow movement away from the 

 light resulting. 



In the very oldest larval stages they are also stimulated by light. 

 A large larva found March -1 seemed annoyed by the light, especially 

 when it was flashed suddenly on and ofi^^. This larva was approaching 

 transformation. The gills were quite small, the tail had lost some of 

 its keel, and in the shape of both body and head it resembled an adult. 

 Besides these changes, the larval coloration, while not yet lost, was 

 supplemented by the characteristic spots of the adult. Other habits 

 of larvae at this stage are of interest and are best known to us from 

 the study of specimens in the laboratory. 



a Am. Nat, XXXIII, 1899, p. 242. 



