INTKODUCTION". XV 



Sciences, at the session held at Washington, April, 1874; I have, however, 

 left out the families Brachyceridce, Amycteridm and Belidce, defined in 

 that essay, but which are not represented in our fauna. 



There are three series, composed of eleven families, represented in Tem- 

 perate and Arctic North America, which may be diagnosed as follows : 



I. Abdomen (^ 9 alike ; pygidium small, elytra without lateral fold on 



inner surface HAPLOGASTRA. 



Labrum distinct, mandibles flat, simple Rhinomaceridae. 



Labrum wanting : 

 Mandibles flat, toothed on outer and inner edge Rhynchitidae. 



" stout, pincer-shaped Attelabidse. 



II. Abdomen (^ 9 dissimilar ; (J^ with an additional anal segment ; pygid- 



ium large ; elytra with acute lateral fold on in- 

 ner surface ALLOGrASTRA. 



A. Antennae with annulated or solid club. 

 Tarsi narrow, setose. 



Gular margin prominent, prosternum exca- 

 vated Byrsopidse. 



Tarsi dilated, usually with a brush of hair beneatlu 



Mandibles with deciduous tip, leaving a scar Otiorliyncliidse. 

 Mandibles without scar, usually pincer- 

 shaped , Curculionidae. 



B. Antennae with ten or eleven distinct joints Brenthidse. 



III. Abdomen (J^ 9 alike ; elytra with a distinct lateral fold on the inner 



surface HETEROGASTRA. 



A. Pygidium vertical or declivous : 



Antennae geniculate, clubbed ; labrum want- 

 ing ; last spiracle covered by ventral seg- 

 ments Calandridse. 



Antennae straight ; labrum distinct ; last spir- 

 acle not covered by ventral segments ; py- 

 gidium deeply notched to receive sutural 

 apex of elytra. Anthribidse. 



B. Pygidium horizontal, smaller : 



Antennae geniculate, clubbed ; terminal edge 

 of last ventral segment acute, surrounding 

 the last dorsal ; tibiae generally compressed 

 and serrate Scolytidae. 



Antennae straight, with annulated club ; max- 

 illae very large, palpi and ligula feeble Apionidse. 



Among the genera and species described in the present memoir, there 

 will doubtless be many which, with more extended comparisons, will be 

 found identical with those which occur in other regions. It will be a just 



