LeConte] BRENTHINI. 327 



sexual selection, produced by the bloodless combats of these insects; which 

 seem, so far as the records go, to be actuated rather by chivalric sentiment, 

 than by animal passion. 



Tribe II. brekthini. 



Two species of Brenthus collected by Mr. Xantus, at Cape San Lucas, 

 Lower California, which are closely allied to Mexican species, have been 

 fully described by Dr. Horn.* I observe in the males also great variation 

 in the form of the head in different individuals, although the beak, though 

 shorter, is as slender in the (^ as in the 9. and the mandibles are equally 

 small, but different in form; the distance from the eyes to the insertion of 

 the antennie is proportionally longer in the larger males. 



The head is deeply excavated beneath, just in front of the neck, in 

 B. penimularis, while it is only slightly so in B. lucanus. In B. mexi- 

 canus there is a short but deep groove in the same position. The front 

 femora alone are toothed in B. mexicanus and hicanus, while they are all 

 toothed in penimularis. 



Subfamily II. CYLADID^. 



This sub-family represents the tribe Cylades, of Lacordaire, placed by 

 him between Eurhynchns and Apion, and consists of but two genera, one 

 of which, Cylas, occurs in Asia and Africa, while the other, 3fyrmecacelus, 

 is found in Australia. I have sufficiently exposed the characters of this 

 subfamily in the description of the family, and the singular form of the 

 antennaj, as well as the very peculiar appearance of the insect, will enable 

 it to be easily recognized. 



The relations of these insects with Brenthidce were well recognized by 

 Fabricius, Latreille and Olivier, and I know not for what reason they have 

 been lost sight of by more recent observers. 



CYLAS Latr. 



1. O. formicarius Olivier, Ent. 84, bis, p. 446; Tab. 2, f. 19; Brentm 

 form. Fabr.,Syst. El. ii, 549; Ent. Syst. Suppl. 174; Attelabm form. Fabr. 

 Ent. Syst. Suppl. 163; C. turcipennis Boh., Sch. Cure, i, 369. Otidoceph- 

 alus elegantulus Summers, New Orleans Home Journal, Jan. and Dec. 

 1875. 



Cochin China, India, Madagascar, Cuba and Louisiana. Depredates on 

 the roots of sweet-potato (^Convolvulus batata). 



Body very elongate, smooth and shining, ferruginous, with the elytra 

 bluish black. Head and beak dusky, the latter twice as long as the head, 

 stout, cylindrical, nearly straight, finely punctured towards the base; au- 

 tennsfi inserted near the middle; eyes smooth, rounded, reticulations very 

 distinct beneath the epidermis. Prothorax twice as long as wide, not con- 

 stricted in front, but very deeply strangulated at the posterior third. Elytra 



* Trans. Am. Ent. Soc. iv, 128. 



