346 ENTOMOLOGICAL SOCIETY 



II. MANDIBLES SUCTORIAL. 

 Ocelli in sixes. 



5. Haliplidce. 



Ninth abdominal segment exserted. Abdomen reptorial. Anten 

 nae frontal. Mandibles explanate. Coxae approximate. Legs with 

 a single claw. Front legs prehensile ; middle and hind legs ambu 

 latory. Head inclined, front greatly elevated at middle; no neck. 



6. Dytiscidce. 



Ninth abdominal segment concealed. Abdomen natatory. An 

 tennae lateral. Mandibles falcate. Coxae distant. Legs cursorial, 

 most frequently natatorial, claws double. Head porrect. Anal 

 segment concealed. Eight pairs of spiracles on the abdomen. 

 Branchiae none. 



7- Gyrinidce. 



Ninth abdominal segment exserted. Abdomen natatorial. An 

 tennae lateral. Mandibles falcate. Coxae distant. Legs ambulatory, 

 claws double. Head porrect. Anal joint exserted, scansatory. 

 Spiracles none. Tracheal branchiae issuing from the sides of the 

 abdomen. 



EXPLANATION OF PLATE III. 



1. Larva of Amphizoa Lecontei from above, enlarged four times. 



2. Same, from below. 



3. Head of larva from below, enlarged ten times. 

 3a. Head, lateral view. 



3b. Left mandible and antenna, from above. 



3c. Maxillae and labium, from below. 



4- Leg. 



4a. Claws, greatly enlarged. 



5. Terminal segment, from above. 



5a. Same, from below. 



Mr. Schwarz remarked that while Amphizoa lecontei had not 

 been bred, there could not be the slightest doubt that the larva 

 described by Mr. Hubbard belonged to Amphizoa. The numer 

 ous images found in City canyon were all, more or less, thickly 

 coated with a layer of mud, thus indicating that the pupa stage 

 was passed in very moist soil ; but the efforts made to dig for the 

 pupa and adhering larval skin remained unsuccessful, owing to 

 the rocky nature of the ground. The general resemblance of the 

 Amphizoa larva to that of a Silphid was unmistakable, so that the 

 first larva seen was taken for that of Pteroloma tenuicornis. 

 This resemblance was still increased from the habit of the larva of 



