.1XTS. 



The symphile.s, as already stated, are nearly all Coleoptera. They 

 belong to the families I'aussidae, Clavigeriche, Pselaphidae, Thorictidae, 

 Cossyphodidae, Silphid;e, Xitidulidae, Ectrephidae, Gnostidae, Scydmae- 

 nidas, Staphylinid.-e, I'.mitlmke and Tenebrionidae. As it will be impos- 

 sible here to describe or even to enumerate the various species, I shall 

 confine myself to -nine of the more striking and interesting types. 



Of all myrmecophilous insects the Paussidae (Fig. 236) are the most 

 extraordinary. They are an aberrant offshoot of the Carabidae, and. 

 with the exception of two species of Hoinoptcrus, that have been taken 

 in equatorial South America, are all paleotropical. Although nearly 300 

 species are known, the behavior of very few has been carefully observed, 

 and the accounts are so different as to indicate a wide range of myrme- 

 cophilous habits within the family. The group, on account of the 

 variety and bizarre structure of its species, is a favorite one with 

 coleopterists. It has been studied by Boyes (1843), Westwood (1843- 

 45). Dohrn (1851), Gueinzius ( i858-'59), Peringuey (1883, 1886), 

 Raffray ( i885-'87 1892 ), Wasmann ( 1888, iSgog, 1894^, 1896/7, 18979, 

 icp4c, etc.) and Escherich (1898, 1907 ). The salient characters of the 

 family are found in the antennae which vary in the number of their 

 joints from n to 2. In the latter case the distal joint is formed by a 

 fusion of several. Wasmann divides the family into four groups of 

 genera according to the number of joints: first, Protopaussus with u 

 joints; second, Arthropterns, Hoinoptcrus, Orthopterus, Ceraptcrus and 

 Plcnroptcrns with 10 joints; third, Ceratoderus, Merismodcrus and 

 Pentaplatarthrus with 6, and Paussoidcs with 5 joints; and fourth, 

 Lcbiodcrus, Platyrhopalus, Paussomorphus, Paussus and H\lotorus 

 with two joints. Several of these groups, of which Paussoidcs is one, 

 were already represented in the Prussian amber (Lower Oligocene). 

 These beetles are not only anomalous in the number of joints in the 

 antenna?, but also in the form of these organs, which in some species 

 are broad and elliptical, in others shaped like ribbons, antlers, scimitars, 

 drumsticks, boats, etc. Westwood described Paussus splucrocenis as 

 having phosphorescent antennae " like two lanthorns spreading a dim 

 phosphoric light," and Wasmann believes that this observation is cor- 

 rect, as the two spherical antennal clubs in a cabinet specimen examined 

 by him had a peculiar yellow color like the phosphorescing spots on 

 the thorax of Pyrophorus. The remarkable development of trichomes 

 in some of the species and their absence in many others indicate that 

 these beetles are not all symphiles, though they are probably all myrme- 

 cophiles. In some forms, like Paussus cucnllatus, the tufts of golden 

 hairs may be present on the pygidium, in the median thoracic groove, 

 in the double frontal pits and in the clefts of the antennal clubs. In 



