86 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



4. Posterior arms of anal sclerite (X-shaped) extremely short. 



mcxicanum Bellardi 

 Posterior arms reaching at least to sides of eighth segment 5 



5. Only one flat tooth on inner margin of mandible ; cephalic fan with fewer than 



50 branches 6 



Two flat teeth on inner margin of mandible; cephalic fan with more than 50 

 branches 7 



6. Occipital cleft rounded; cephalic fan with 46 branches; submentum with 



apical teeth well developed, with 9 hairs in ventrolateral row, and with 3 or 



4 teeth on each of its lateral margins yepocapense Dalmat 



Occipital cleft pointed ; cephalic fan with 36-40 branches ; submentum with 

 apical teeth poorly developed, with 8 hairs in ventrolateral row, and with 5 

 teeth on each of its lateral margins carlei Vargas, Martinez, and Diaz 



7. Posterior sucker with 220-230 rows of hooks ; submentum with 9 hairs in 



ventrolateral row ; anal gills with 36 short branches ; posterior arms of anal 

 sclerite extending well onto the sides of the eighth segment. 



rtibicundulum Knab 



Posterior sucker with 264-270 rows of hooks ; submentum with 7-8 hairs in 



ventrolateral row ; anal gills with 27-45 branches ; posterior arms of anal 



sclerite not extending to the sides of the eighth segment. . .mathesoni Vargas 



SPECIES OF THE SUBGENUS HEARLEA, BASED ON LARVAL CHARACTERS 



1. Eighth segment with large, heavily sclerotized, and deeply pigmented dorsal 



and/or ventral processes 2 



Eighth segment without such processes 3 



2. Cephalic fan with 57-58 branches ; ventrolateral row of submentum irregular, 



composed of 13 hairs, sometimes grouped in pairs ; pseudopod with 72-74 

 rows of hooks ; occipital cleft rather narrow and acute ; length of mandible 

 2.3 times the width ; 2 black transverse bands, i on either side of midline, 

 crossing larva just anterior to anal gills, at times meeting at midline. 



larznspinosnm De Leon 



Cephalic fan with 44-45 branches; ventrolateral row of submentum with 8-11 



hairs in straight line ; pseudopod with 45-46 rows of hooks ; occipital cleft 



dome-shaped, somewhat pointed anteriorly; length of mandible 1.6 times the 



width; without black bands anterior to anal gills carolinae De Leon 



3. Posterior sucker with 170 or less rows of hooks 4 



Posterior sucker with more than 170 rows of hooks 5 



4. Posterior sucker with 1 14-125 rows of hooks; cephalic fan with 44-45 



branches ; ventrolateral row consisting of 6-10 hairs in straight row, either 

 trifid or 4-branched ; each of 3 anal gills branching into 4, giving 12 ramifi- 

 cations in all ; rectal scales in irregular group near union of anterior arms 



of X-shaped sclerite capricornis De Leon 



Posterior sucker with 160-170 rows of hooks; cephalic fan with 34-37 

 branches; ventrolateral row of submentum composed of 12-16 hairs in 

 irregular row, simple to trifid; anal gills with 12-13-12 fingerlike branches, 

 giving total of 37 ; rectal scales in 3 or 4 almost regular rows in front of 

 anterior arms of X-shaped sclerites ethelae Dalmat 



5. Ventrolateral row of submentum composed of 14-15 hairs; posterior sucker 



with 172-178 rows of hooks ; cephalic fan with 46-50 branches ; anal gills 



