Family PTILODACTYLIDAE 



These oval to elongate beetles are brown to black in 

 color and are usually found along the margins of 

 streams. The larvae of some are aquatic but those of 

 others feed upon the roots of grasses or are found in 

 leaf mold. The larvae are of the elongate cylindrical 

 burrowing type. The aquatic forms have the last 

 abdominal segment flattened above and may have 

 gills situated about the anus or on the ventral side 

 of the abdominal segments. 



Relationships. — There is considerable confusion 

 as to which genera should be included in this family. 

 Originally it was placed as a subfamily of Helodidae 

 and included Lachnodactyla and Ptilo dactyl a. On the 

 basis of larval characters, Boving (1931) made it a 

 family and included Eurypoyuu and Anchytarsus, 

 formerly placed in Dascillidae. He also figured an 

 unassociated larva from China as belonging in this 

 family. Larvae almost identical to that figured have 

 been collected in California, and on the basis of 

 distribution and size have been associated with 

 Stenocolus. Another California larva close to Anchy- 

 tarsus on the basis of size has been associated with 

 Anchycteis. 



Respiration. — Only the larvae of certain genera are 

 known to be truly aquatic. Whether the adults ever 

 enter the water is not known. The larvae of all genera 

 have the usual spiracles on the mesothorax and the 

 first eight abdominal segments. In addition, two types 

 of gills are found on the aquatic forms. Larvae of 

 Anchytarsus and Anchycteis have fingerlike gills in 

 the anal region on the ventral side of the ninth ab- 

 dominal segment. There are only five such gills in 

 Anchycteis, which would seem insufficient to maintain 

 them below the surface for any length of time. How- 

 ever, the integument has the shining gloss seen in 

 the larva of Dryops, which is reported to carry a film 

 of air about the entire body. The Stenocolus larva has 

 two tufts each composed of eleven to twelve fingerlike 

 gills on the underside of abdominal segments one to 

 seven. 



Habitat and distribution. — Adults of Stenocolus are 

 found along streams entering the Sacramento and San 

 Joaquin valleys of California, up to an elevation of 

 4,000 feet. Associated larvae have been taken in 

 about the same area in streams varying from small 

 creeks to rivers. They burrow in the substratum of 

 the stream, feeding upon the roots of trees and other 

 vegetation. Larvae associated with Anchycteis have 

 been taken in northern California in spring areas and 

 small- to medium-sized rapidly flowing creeks. Pre- 

 sumably they have approximately the same habits as 

 Stenocolus. 



Key to the Neareric Genera of P tllodocty I idae 



Adults 



1. Mandibles prominent, acutely margined above (margin 

 often hidden by pubescence), rectangularly flexed at 

 tip, head not retracted; thorax acutely margined .... 



Stenocolus LeConte 1853 



Stenocolus scutellaris LeConte 1853; central 

 California along streams. 



367 

 Leech and Chandler: Coleoptera 



— Mandibles not prominent, arcuate at tip, not acute 1) 

 margined above, head strongly doflexed; I . uder 



2 



2. Antennae slender; middle coxao not more widely 

 separated than the anterior pair; thorax obtusely mar- 

 gined, prosternum moderately long before the coxae 

 Anchytarsus Cuerin 1843 



Anchytarsus bicolor (Melsh.) 1846; New York to 



Georgia 

 Antennae serrate (pectinate in male), moderately long; 

 middle coxae twice as widely separated as the anterior 

 pair; margin of thorax very obtusely rounded, prosternum 

 short in front of the coxae Anchycteis Horn 1880 



Anchycteis velutina Horn 1880; northern California, 



in springs and rapid streams. 



Larvae 



1. Two tufts of gill filaments on underside of abdominal 

 segments 1-7, 9th segment without prehensile hooklike 

 appendages; submentum not divided (fig. 13:196) 



Stenocolus LeConte 1853 



— Anal area of 9th abdominal segment with short finger- 

 like gills and 2 prehensile curved appendages covered 

 with short stout spine; submentum divided longitudi- 

 nally into 3 parts 2 



2. With only 5 fingerlike gills, 3 anal and 1 on outer 

 side of each prehensile appendage; dorsal flattened 

 spex of 9th abdominal segment with small raised pro- 

 jection Anchycteis Horn 1 880 



— With 21 fingerlike gills; apex of 9th abdominal segment 

 without projection (fig. 13: 19c) 



Anchytarsus Guerin 1843 



REFERENCES 



BOVING, A. G., and F. C. CRAIGHEAD 



1931. An illustrated synopsis of the principal larval 

 forms of the order Coleoptera. Ent. Amer., 11:1-351, 

 125 pis. 

 LECONTE, J. L., and G. H. HORN 



1883. Classification of the Coleoptera of North America. 

 Smithson. Misc. Coll., No. 507, xxxviii+568 pp., 

 70 text figs. 



Family CHRYSOMELIDAE 



This large family contains one subfamily, Donaciinae, 

 and one species in the subfamily Galerucinae which 

 are closely associated with aquatic plants. The grub- 

 like larvae of Donaciinae (which contains about sixty 

 species) are truly aquatic, and the adults of some 

 species may make short excursions under water. The 

 larvae and adults of Galerucella nymphaeae feed only 

 on the upper surface of floating leaves. The Chry- 

 somelidae are characterized by their tarsi which have 

 the fourth segment reduced and hidden between the 

 lobes of the third. They are usually separated from 

 the Cerambycidae by their oval form and shorter 

 antennae, though the Donaciinae resemble the Ceram- 

 bycidae to some extent in this respact. For this 

 reason they are sometimes called the longhorn leaf 

 beetles. Galerucella is a typical chrysomelid. 



Relationships. — The Donaciinae have developed 

 their aquatic adaptations independently of the rest 

 of the Chrysomelidae, and for this and other reasons 

 are sometimes placed in a separate family Donaciidae. 



Respiration. — The larvae of Donacia have the 

 dorsally placed spiracles of the eighth abdominal 



