COPROPHAGOUS BEETLES A^"D METHODS OF REARING THEM 7 



When conditions are optimum, hundreds of earthen mounds cov- 

 ering the burrows of these beetles can be seen within a few hundred 

 yards. In one pasture 50 mounds were found on a ^ -acre plot and 

 at another place a count on a tV-acre area showed 168 mounds. 



The egg is creamy white and similar to other dung-beetle eggs ; the 

 average diameters are 5.45 and 3.60 mm. The incubation period is 

 4 to 8 days and the pupal period 10 to 14 days. The egg balls used 

 for study of immature stages were obtained by digging up nests in the 

 field immediately after rains. 



The average developmental period from egg hatching to adult 

 emergence at the laboratory in the spring and summer was 35.4 days, 

 with a minimum of 29 and a maximum of 44 days. There are indi- 

 cations that in the field the developmental period is shorter. Three 

 larval instars were found, and the data are shown in table 1. 



The larvae of this species, as well as of C. lecontei and probably 

 other species of Canthon, at intervals make holes in the smaller end 

 of the ball and excrete a black, moist, pasty mass, which soon hardens 

 and forms a collar of protruding nodules around the small end of 

 the ball. The excreta may occasionally be found on other parts of 

 the ball. 



CANTHON LECONTEI Har. 



This species, although much smaller than C. laevis, has similar 

 habits. The beetles are abundant in the spring and occasionally are 

 very active in October. The ball they construct and roll is from 

 one-fourth to three-eighths inch in diameter and is buried from 1 to 3 

 inches in the ground. The incubation period is 4 to 6 days. In June 

 the period from egg hatching to adult emergence averages 24.3 days. 



CANTHON CYANELLUS lee. 



Although this species is fairly abundant at Uvalde, the eggs or 

 immature stages have never been seen. The beetles are found in 

 cow droppings but most abundantly at meat baits. They are at- 

 tracted to the meat baits in blowfly traps, and often 25 or more 

 are drowned in the bait pans. They have been observed at small 

 carcasses and human excrement. A beetle was once seen rolling a 

 ball that had been carved from a piece of decaying liver. 



ONTHOPHAGUS ANTHRACINUS Har. 



Specimens of Ontliofliagus anthracinus Har. are found in dung 

 from March to December, and a hundred or more have been counted 

 in a single dropping. Species of Onthophagus perform their dung- 

 burial under a dropping. A burrow is dug vertically into the 

 ground to a depth of 1 to 4 inches, and dung is transported into 

 the lower extremity, where it is fashioned into a crude ball in which 

 an egg is laid. 



Reared females have deposited from 43 to 67 eggs over periods of 

 22 to 42 days. Only 1 or 2 eggs are laid daily, and they average 

 1.56 by 0.74 mm in diameter. The average developmental period 

 from egg to adult in summer was 38.4 days, with a range of 36 to 

 52 days. Notes on the number of instars are not complete, but indi- 

 cations are that there are three. 



