THE GREEN JUNE BEETLE. 



19 



egg-laying. This matter of the dung- feeding habit will be discussed 

 further under the heading " History and literature," p. 28. 



Period of Incubation. 



The period of incubation in the field, as will readily be understood, 

 depends in a large measure on climatic conditions for that period, and 

 moisture particularly plays a part in the development of the em- 

 bryonic larva. This fact has been illustrated with eggs kept in the 

 laboratory in vials. It was determined that the eggs when first 

 deposited are small in size, but with suitable moisture conditions 

 finally become larger and assume the spherical shape, the larvae 

 hatching within a period varying from 12 to 14 days. Eggs kept in 

 vials in which the sand is allowed to become dry remain small and 

 will not develop until suitable conditions of moisture occur. The in- 

 cubation period is then very much prolonged, and the resulting 

 larvae are not so vigorous and are somewhat smaller than the 

 average. Usually the normal period is from 10 to 15 days. The 

 depth at which the eggs are deposited in the field provides a tempera- 

 ture nearly uniform, and even during dry weather the moisture con- 

 tent of the soil at a depth of from 6 to 8 inches can be but slightly 

 affected. The length of the incubation period, as observed in eight 

 instances, is given in Table I. 



Table I. — Incubation period of Cotinis nitida. 



No. 



Date of 

 deposi- 

 tion 

 of eggs. 



• Date of 



hatching 



of 



larvae. 



Incuba- 

 tion 

 period 

 (days). 



1 



Aug. 5 

 Aug. 14 

 Aug. 16 

 Aug. 21 

 Aug. 23 

 ...do 



Aug. 17 

 Aug. 23 

 Aug. 30 

 Sept. 3 

 Sept. 6 

 Sept, 7 

 Sept. 13 

 ...do 



12 



2 



9 



3 



14 



4 



13 



5 



14 



6 



15 



7 



Aug. 25 

 Aug. 30 



19 



8 



14 







Oviposition in Tidewater Virginia. 



All the pupal cells obtained in 191() were placed in a large cage, 

 and adults began to issue in July. Table II shows! the date of copu- 

 lation, the number of masses of eggs deposited by each female thus 

 separated, and the total number of eggs deposited. A pair in copu- 

 lation was isolated and a record made of ^egg laying. Flowerpots 

 containing an equal mixture of sand and soil, having an abundance 

 of organic matter, and about 9 inches in depth, were used for study, 

 and were examined frequently, the examination being greatly facili- 

 tated by the ease with which the soil was removed entire from the 



