PARASITIC-BEETLES. 113 



to refer to some of tlie most common instances of this change in the 

 introductory i)art of tb is work, and the same is strikingly illustrated 

 in the history of the present tribe, in which the same species is often 

 parasitic in its larva state, whilst it feeds upon the flowers or foliage of 

 plants in its perfect or imago state. 



The following is a table of the families of the Trachelides : 



A. Constriction of tlie neck gradual and slight ; anterior coxal cavities closed behind.* 



Size medium LAGRiroiE. 



A A. Neck distinct and al)rupt ; anterior coxal cavities always open behind. 



B. Thorax with a lateral margin ; iibdomeu usually tapering to a long point ; hind 



legs long and flat. Size small Mordellid^. 



B B. Thorax rounded at the sides; abdomen not pointed. 



C. Tarsal claws deeply cleft. Size large or medium Meloid^. 



C C. Tarsal claws entire. 

 D. Thorax narrower behind than the elytra. 

 E. Antennae almost always filiform and simple. Size very small . Anthicid^. 

 E E. Antennae usually branched in the male, serrate in the female. Size 



medium or small PYROcnROiD^. 



D D. Thorax as wide behind as the elytra. Size small Rhipiphorid^. 



AAA. Without visible neck — structure very abnormal. Size very small . Sttlopid^. 



Family XLII. LAGRIID^. 



This family is comprised of a small number of medium sized beetles, 

 which furnish a connecting link between the Trachelides and the Teue- 

 brionidie ; having an imj)erfect neck, and being rather soft and flexi- 

 ble like the former, but having the anterior coxal cavities closed behind, 

 like the latter. Mr. Westwood states that he has found the larva of the 

 European Lagria hirta on white thorn hedges; and Lyonet mentions 

 having discovered the same under dead leaves upon the ground. 



There are but five IST. A. species of this family. The Lagria (Ar- 

 tliromacra) a^nea, Say, is an elongate brassy-black beetle, nearly half an 

 inch in length, and easily recognized by the remarkably elongated ter- 

 minal joint of the antennte, which is as long as the four preceding 

 joints taken together. 



Family XLIII. MORDELLID^. 

 This family contains a considerable number of small beetles, rarely 

 more, and usually less than a quarter of an inch in length, and distin- 

 guished by their elliptical and arched form, the head being bent down 



* The state of the anterior eoxal cavities as respects their being closed or open behind, is a charac- 

 ter of considerable importance in classifying the Coleoptera, especially the Hoteromera. The coxal 

 cavities are the hollows in the sternum or breast plate in which the legs are inserted. The anterior cav- 

 ities are sometimes wholly surrounded by the crust of the sternum, when they are said to be closed ; 

 in other cases there is a deficiency of the sternum directly behind the anterior costu, which is filled by 

 membrane, and the cavity is then said to be open. 



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