Fig. 13:19. Larvae of Noteridae and Ptilodactylidae. a, Noierus 

 sp.; b, Sfenoco/us sp.; c, Anchytarsus sp., ninth abdominal seg- 

 ment (a, Wesenberg-Lund, 1912; b,c, Boving and Craighead, 1931). 



is over a hole bitten into the root, the cocoons being 

 filled with air which escapes from the root. 



Life history. — The eggs are presumed to be laid in 

 summer, on the roots of plants a foot or so under 

 water, or in the mud close by. Freshly emerged adults 

 appear in early August, and the winter is passed in 

 the adult and perhaps also in the larval stage. Co- 

 coons are formed on plant roots under water, as 

 mentioned in the preceding paragraph (see fig. 3 in 

 Balfour-Browne). 



Habitat and distribution. — The typical streamlined 

 noterines, such as the Old World Noterus, Hydro- 

 canthus (Old and New Worlds), the New World 

 Suphisellus, and to a lesser extent our Pronoterus, 

 are active beetles and strong swimmers. The tiny 

 Notomicrus is more suited for crawling, and clinging 

 to underwater objects, whereas the nearly hemispher- 

 ical Colpitis (and the very similar Central and South 

 American Suphis), with hind legs but little modified 

 fo - I swimming, spends most of its time in the debris 

 at the bottom. All of them occur in weedy ponds and 

 lakes. The species of Pronoterus fly to lights at 

 night. Jackson (1950) studied the wings of the two 

 British species of Noterus. In N. capricornis Herbst, 

 she found that though the wings were fully formed and 

 of normal size, the muscles of flight were absent. In 



325 

 Leech and Chandler: Coleoptero 



A', clavicornis Degoor the wings were either brachyp- 

 terous, or partly reduced in size. However, in earlier 

 studies in weevils of the genus Si to mi, she discovered 

 that certain fully winged individuals which wore seen 

 to fly in the fall, had the flight muscles degenerate 

 and functionloss by spring. 



The family is represented in the warmer parts of 

 both hemispheres, and widely distributed therein. 

 Hydrocanthus occurs in North, Central, and South 

 America, Africa, Madagascar, Burma, Java, and in 

 adjacent areas; Suphisellus of the New World is 

 closely allied to Canthydrus of the Old; Colpius and 

 Pronoterus are Neotropical, reaching Florida in the 

 United States, whereas the aberrant Notomicrus has 

 a similar distribution, but extends also to Australia. 



Taxonomic characters. — Color pattern is of some 

 value in separating the species of Suphisellus, and 

 punctation of the dorsum is useful in most genera. 

 Characters of greatest use are found in the shape of 

 the tibiae, the form of the prosternal and hind coxal 

 process, the punctation of the ventral surface. In 

 some genera the apex of the prosternal process may 

 differ in shape in the sexes of one species, as may 

 the form of the metasternum. 



Key to the Genera of Noteridae of the United States 7 

 Adults 



1. Apex of front tibiae bearing more or less conspicuous 

 curved spurs or hooks (fig. 13:18c) 2 



— No spurs or hooks on front tibiae; small beetles, 

 rarely exceeding 1.5 mm. in length (fig. 13:18a) .... 



Notomicrus Sharp 1 882 



2. Front tibial spurs strong and conspicuous; hind femora 

 with angular ciliae; prosternal process truncate behind 

 (or if rounded in male, body form very broad, almost 

 hemispherical) 3 



— Front tibial spurs weak and inconspicuous; hind femora 

 usually without angular ciliae; prosternal process 

 rounded behind in both sexes (fig. 13:186) 



Pronoterus Sharp 1 882 



3. Laminate inner plates of hind coxae truncate at apex 

 with an arcuate emargination on each side of the 

 depressed middle; hind coxal cavities separated; 

 prosternal process truncate in female, rounded in 

 male (fig. 13:18c) Colpius LeConte 1861 



— Laminate inner plates of hind coxae with a broad 

 and deep angular excision at apex, leaving on each 

 side a diverging triangular process (fig. 13:20); hind 

 coxal cavities contiguous 4 



4. Apex of prosternal process at least twice its breadth 

 between coxae, not broader than long; last segment 

 of maxillary palpus emarginate at apex; pronotum with 

 lateral marginal lines originating at hind angles but 

 disappearing at about middle; beetles usually less 

 than 3: mm. in length Suphisellus Crotch 1873 



— Apex of prosternal process very broad, at least 2.5 to 

 3 times its breadth between coxae, broader than long; 

 last segment of maxillary palpus truncate at apex; 

 pronotum with lateral marginal lines the entire length 

 of margins and joining front margin anteriorly; beetles 

 usually between 4 and 5.5 mm. in length 



Hydrocanthus Say 1823 



Key to the Known Genera of Nearctlc Noteridae 

 Larvae 



1. Mandibles slender, narrowly sulcata at tip, simple; 



'Key supplied by Dr. Frank N. Young. 



