Casey — A Revision of the American Paederini. 91 



specimens, in which the coloration of the elytra is perfectly 

 constant, except in one individual, where the red is replaced 

 by a piceous-black ; as the other specimens are constant, this 

 dark coloration may be accidental. 



There is no group of species known to me, showing more 

 plainly the subgeneric value of types of male secondary sexual 

 characters, than these components of Lathrobhctn, for we 

 have successions of what are without doubt distinct, though 

 closely related, species, having throughout the same type of 

 sexual modifications, which types are abruptly limited in ex- 

 tent and without intermediates, as shown by the above table. 



The name simplex was replaced hy fauveli by M. Duvivier, 

 (Cat. 1883) on the ground of preoccupation, but I am by no 

 means certain that the older simplex is really a Lathrohium,, 

 and therefore have not made the change of name. 



There are four described species of Laihrohium which are 

 not before me at present ; these are appended below with 

 short descriptions which I drew up some years ago from the 

 original unique types. They are all very distinct species and 

 will undoubtedly have to be removed from the restricted 

 genus Lathrohium, but having failed to record any observa- 

 tions upon the elytral flanks, gular sutures or structure of the 

 hind tarsi, I am unable to dispose of them among the other 

 genera at present, and indeed some of them are so isolated 

 as to indicate new genera. For the present however they 

 may be attached to Lathrohium : — 



Form moderately slender, parallel, head gradually and slightly narrowed 

 behind the eyes to the neck, which is broad, the surface coarsely and 

 remotely punctate; antennae not very thick, as long as the head and 

 prothorax, the latter about as long as wide, equal in width to the head, 

 the punctures coarse, sparse and rather feebly impressed; elytra about 

 as long and wide as the prothorax, the punctures very coarse, not close- 

 set and rather feebly impressed, arranged in series throughout; ab- 

 domen finely and sparsely punctulate. Male having a feeble, transversely 

 oval medial impression on the fourth ventral — possibly accidental, — 

 the fifth very minutely, feebly sinuate and extremely feebly impressed 

 at apex, the sixth with a broad angular emargination, occupying the 

 entire apex and at least five times as wide as deep. Length 5.7 mm. ; 

 width 0.9 mm. North Carolina seriatnm Lee. 



Form subparallel and rather stout, convex, dark rufo-testaceous, the head 

 blackish; elytra rufous, with a large median blackish cloud extending 



