Il^TRODUCTION. XV 



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

 left out the families BraGliyceridcB, Amycteridce 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 (j^ 9 f^like ; 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 (J' 9 dissimilar ; (^ with an additional anal segment ; pygid- 



ium large ; elytra with acute lateral fold on in- 

 ner surface ALLOGASTRA. 



A. Antenuaj with annulated or solid club. 

 Tarsi narrow, setose. 



Gular margin prominent, presternum exca- 

 vated Byrsopidae. 



Tarsi dilated, usually with a brush of hair beneath. 



Mandibles with deciduous tip, leaving a scar Otiorhynchidse. 

 Mandibles without scar, usually pincer- 

 shaped Curculionidse. 



B. Antennse with ten or eleven distinct joints Brenthidae. 



III. Abdomen (^ 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 Calandridae. 



Antennse straight ; labrum distinct ; last spir- 

 acle not covered by ventral segments ; py- 

 gidium deeply notched to receive sutural 

 apex of elytra Anthribidae. 



B. Pygidium horizontal, smaller : 



Antennse geniculate, clubbed ; terminal edge 



of last ventral segment acute, surrounding 



the last dorsal ; tibiaj generally compressed 



and serrate Scolytidae. 



Antennse straight, with annulated club ; max- 



illse very large, palpi and ligula feeble Apionidae. 



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 



