674 Goleopterological Notices, VI. 



terior lobe large, transverse, widest at its anterior third, tlie sides convergent 

 and rounded to the acute constriction ; posterior lobe distinctly less than one- 

 third the total length, rapidly expanded to the basal margin. Elytra nearly 

 twice as long as wide, twice as wide as the prothorax, distinctly wider at the 

 middle than at base or apex, the latter subeqxial, the apex broadly arcuate; 

 humeri broadly exposed at base, the mes-episternum not at all visible from 

 above ; punctures coarse and sparse, rather closer and finer toward the suture ; 

 pubescence short and stiff, sparse but pale and distinct throughout. Abdomen 

 alutaceous, finely pubescent. Legs modei-ate in length and rather stout. 

 Length 3.1 mm.; width 0.95 mm. 



California (near San Francisco). 



The single male before me indicates a species which is appreci- 

 ably larger than californicus, and the sexual characters are quite 

 different. The fifth ventral is short and but slightly longer 

 than the fourth, its apex broadly, just visibly sinuate, and its disk 

 unmodified ; genital segment deeply, angularl3' emarginate in the 

 middle at apex, the emargination but slightly' luore than twice as 

 wide as deep, the disk with a large deep and transversely oval 

 impression, and the posterior edge fringed with stiflT, inwardly di- 

 rected cilia. In this specimen the extreme tip only of the copu- 

 latory sheath is exposed, but this is much broader and more ob- 

 tuse than in californicus, and there is, in addition, a slender thin 

 fillet at each side of the sheath-apex, of which I can find no homo- 

 logue whatever in that species. 



VACUSUS n. gen. 



The members of this genus are small, narrow and usually pol- 

 ished, sparsely punctate and pubescent species, of peculiar facies, 

 but not unremindful of some of the various forms of Anthicus. 

 They also resemble Anthicus in antennal, oral and crural struc- 

 ture, but differ completely in the entire conformation of the meso- 

 sternum, as detailed in the table of genera. They present three 

 t^'pes, quite distinct in appearance and environment, represented 

 by Isetus, nigritulus and formicetorum, the first inhabiting the 

 Southei'u State? from Florida to southern California, the second 

 peculiar to the true Pacific coast fauna, and the third to the desert 

 regions of the Sonoran province. The latter is remai'kable, in 

 addition to its peculiarities of facies, in that its closel}' allied 

 components are mynnecophilous in habit, tlie symbiosis how- 

 ever probably not being complete. 



The species may be separated as follows : — 



