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 rarely entirely round ( Conosoma , several Stenue species). It varies in form, 

 sometimes of uniform breadth and only tapering posteriorly, and again more 

 smoothly tenuis, occasionally narrowing up toward the metathorax ( Tachyusa 

 constricta Fig. 88 et al. ) not infrequently f eetly spool- or fusiform. 

 Then running, and in fear, also often at rest, many Staphylinids raise ab- 

 domen up in the air or bend it forward over the forebody, probably to cover 

 this or to produce a different appearance. Sometimes this tendency has be- 

 come a fixed habit, which not only distinguishes the appearance of the ani- 

 mal but also the structure of its body (cf. Bncephalus ) . Where the flexibi- 

 lity forwardly is developed, several of the foremost free dorsal segments 

 most often three, sometimes four, are depressed or transversally grooved at 

 base. Most of the Tachyporines and many species with long elytra curve ab- 

 domen downward and inward toward ventral side; some of the Xantholines when 

 in danger bend the forebody in toward metathorax and in this position lie atill, 

 apparently dead. 



The difference between the sexes is not always externally distinct, but 

 in a great number of species in all groups it is however apparent, especially 

 in the S' , in external sex-characters. The sex- characters often consist of 

 spines, teeth, carina©, grooves or incisions on one or several of the last 

 abdominal segments either on dorsal or ventral side. But also on head and 

 pronotum formations and impressions often occur in the c?', which arc not found, 

 or less distinct in the ^ (such as horns in Bledius species). Sometimes the 

 head in S is larger than in p ( Philonthus et al.), or the fore-tarsi are di- 

 lated, or the foremost antennal joints more densely haired on inner side, 



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