522 THE STUDY OF INSECTS. 



ed in our fauna by two species of Amphizoa (Am-phi-zo'a), 

 which occur in Northern California, Utah, and Vancouver, 

 clinging to logs or stones under the surface of streams. 

 In these beetles the metasternum is truncate behind, not 

 reaching the abdomen, and has a very short antecoxal 

 piece. 



^ Family HALIPLID^E (Ha-lip'li-dae). 

 The Haliplids (Hal' i-f lids). 



This family includes a few species of small aquatic beetles, 

 which are oval, more or less pointed at each end, and very 

 convex. The wing-covers have rows of punctures, and the 

 hind coxae are greatly expanded so as to conceal the 

 basal half of the hind femora and from three to six of the 

 abdominal segments. 



These beetles are not uncommon in ponds and streams, 

 but they swim poorly. Only three genera occur in this 

 country. In Brychius (Brych'i-us), which is represented by 

 one species from California, the prothorax is quadrate ; in 

 the other genera it is narrowed in front. In Haliplus (Hal'- 

 i-plus) the last segment of the palpi is small and awl-shaped; 

 in Cnemidotus (Cnem-i-do'tus) it is longer than the third seg- 

 ment, and conical. 



The larvae are aquatic, occurring near the shores of 

 ponds and streams and in other damp places. The body is 

 rather slender ; each segment except the head is 

 furnished on the back with fleshy lobes with spiny 

 tips, which vary greatly in size in different species ; 

 and the last segment bears a long tapering appen- 

 dage. Figure 629 represents a larva of this family, 

 which we found in large numbers in a pond swarm- 

 ing with Cnemidotns ; it probably belongs to this 

 genus. The larvae of several species of Haliplus 

 FIG. 6 29 . are fi gurec j by Schiotde, but in each of these the 

 caudal appendage is forked. 



