4 CIRCULAR 3 51, U. S. DEPARTMENT OF AGRICULTURE 



with a range of 38 to 69 days. The pupal period ranged from 12 

 to 37 days. Of 48 reared beetles 32 were females and 16 males. 



To determine the number of larval instars and the time in each 

 instar it is necessary to open the ball, remove the larva for meas- 

 urement of the head capsule, replace the larva, and repair the 

 ball, which after a number of examinations may become ragged 

 and weak. It was nearly impossible to find the cast skins except 

 immediately after molting. Three larval instars were found, and 

 the data concerning them are shown in table 1. 



Table 1. — Data on instars of three dung beetles 



Species 



Instar 



Time in instar 



Measurement of head 

 capsule 



Maxi- 

 mum 



Mini- 

 mum 



Aver- 

 age 



Maxi- 

 mum 



Mini- 

 mum 



Aver- 

 age 





[First 



Bays 

 4 

 5 



0) 

 6 

 4 



0) 

 3 

 3 



0) 



Bays 

 2 



2 

 0) 



3 



4 

 0) 



1 



2 



0) 



Bays 

 2.9 

 3.7 

 0) 

 4.1 

 4.0 



0) 

 1.8 

 2.5 



0) 



Mm 



2.1 

 2.5 

 3.0 

 2.8 

 3.2 

 4.2 

 2.2 

 2.8 

 3.2 



Mm 



1.8 

 2.2 

 2.8 

 2.5 

 3.0 

 4.0 

 2.0 

 2.4 

 2.9 



Mm 

 1.97 

 2.35 

 2.94 

 2.66 

 3.10 

 4.12 

 2.10 

 2 65 





{Second 



[Third 







[First 



{Second 



[Third 



[First 



^ Second 



[Third 







3.13 



Not determined. 



Eggs have been obtained as early as March 20, and as late as 

 October 10. 



The longevity of the adult is interesting. One reared female lived 

 644 days, and several beetles have laid eggs over two seasons. Un- 

 der normal conditions females probably live 4 years and possibly 

 longer. Since the parent stays with her progency until they emerge as 

 adults, only 3, or sometimes possibly 4, batches of eggs are laid 

 in a year. Twelve batches have been obtained from a single female 

 during a 14-month period without a decrease in number of eggs 

 per batch, when the progeny were taken away from the nest from 

 5 to 14 days after deposition, and it seems reasonable to suppose 

 that 4 years would normally be required to lay 12 batches of eggs. 



PHANAEUS TRIANGULARIS (Say) 



The burrows of this beetle have never been found on the plains 

 around Uvalde, but after rains they have been observed about 30 

 miles north of Uvalde on the escarpment of the Edwards Plateau, 

 but only in the river valleys. Although the river bottoms close to 

 Uvalde have been searched, only one burrow has been discovered. 

 Apparently the species seeks localities close to streams and does not 

 thrive in hot, dry plains. 



This species also burrows at the edge of cattle droppings. In 

 the field these burrows have been found to be branched, the main 

 tunnel being from 6 to 12 inches long and about three-fourths inch 

 in diameter, and the branch, which is used for dung storage, from 



