LARVAL FORMS OF COLEOPTERA 



slioi-t Helophoridae {Helophorus) (pi. 21 A, 



D, E) 



3. Head slightly inclined ; antenna inserted nearer the lateral 



margin of the head than is the mandible; ventral monthparts 

 retracted ; gula veil developed, quadrangular, and attaining 



the occipital foramen 4 



Head elevated ; antenna inserted farther from the lateral mar- 

 gin of the head than is the mandible ; ventral mouthparts 

 protracted ; gula reduced to a triangular pregular plate and 

 a single, median, posterior gular suture 5 



4. Mandible apically bifid and without molar part; maxillary 



stipes with strong projecting lacinia ; maxillary palpiger 

 with long, conical galea; abdominal segments soft, with short 

 conical gills(f); last three abdominal segments attenuate, 

 not forming a breathing pocket. 



Sperclieidae (Spercheus) (pi. 21 B, 

 C, F-H) 

 Mandible apically ending abruptly and with a terminal, short 

 seta, molar part present ; stipes with rudimentary lacinia ; 

 palpiger without galea ; abdominal segments with well-de- 

 veloped plates ; last three abdominal segments forming a 

 breathing pocket Hiidrochklae (Hydrochus) (pi. 22 A, 



5. Seven pairs of very long gills on sides of abdomen ; no breath- 



ing pocket. (Ninth and tenth abdominal segments appar- 



entlv absent) Hydrophilidae - Berosinae (Bevosus) 



■(pi. 22 B, E) 

 Gills (?) of moderate size or absent; Avith breathing pocket... 6 

 6 Maxillary stipes long and styliform ; femora with fringes of 

 long swimming hairs. (Gills (?) present or absent.) 



Hydrophilidae - Hydrophilinae (H y - 

 drous, Hydrophilus, and Tropisfer- 

 nus) (pis. 22 F, G and 23 A.) 

 Stipes moderately or very broad ; femora without fringes of 



swimming hairs. (Gills absent) 7 



7. Ocellar group often large; ocelli equally developed and rather 

 distant. (Legs generally of normal size and visible from 

 above; abdomen more or less tapering posteriorly; nasale 

 often with more than three teeth ; nasale and anguli frontales 

 often asymmetrical) Hydrophilidae-H tjd rohiinae (pis. 22 

 H-S and 23 B, G, H) 

 Ocellar group small ; ocelli of different size, or closely ag- 

 gregate. (Legs poorly developed or absent; abdomen often 

 truncate posteriorly ; nasale with a single tooth or three small 

 teeth; nasale and aiiguli frontales symmetrical). 



Hydroph ilidae-Sph aeridiiruie ( Ch ae- 

 Uirfhria, (U)eJosto))}o = Cycfonotion, 

 Cercyon, etc.) (pis. 23 C-F, I-P and 

 24 A-T) 

 32 



