72 CEKEAL AND FORAGE INSECTS. 



Occasionally, but not often, the head is thrust from the shell at 

 the beginning of the exit and the body quickly follows. 



The long hairy tips of the thoracic tubercles fall forward over the 

 face when the body emerges first, but become erect as soon as the 

 moisture dries away. 



The date of larval emergence seems to vary widely with the season. 

 No definite information is obtainable prior to 1908, but during that 

 year the first larvae were noticed about the middle of June. It is 

 said that in 1907 they appeared not far from July 1. In 1909 they 

 began to emerge about May 20, and continued to appear until after 

 July 1. The date of oviposition may govern the time of hatching, 

 but the character of the season is without doubt a more potent factor 

 in this matter. 



Dissection of the eggs at various times after oviposition has shown 

 that the embryo forms within a few weeks, and that months before 

 they emerge the larvae are lying within the shells, fully formed and 

 ready to appear at any time when external conditions will permit. 



When removed from their New Mexican environment the eggs 

 hatch much before the normal time. A large number that were 

 gathered late in October, 1908, and taken to Washington, D. C, 

 began to hatch by December 22, at least five months before similar 

 eggs hatched in New Mexico in the following spring. 



A handful of egg clusters gathered from the mesa in Colfax County, 

 N. Mex., March 7, 1909, and taken to the vicinity of Las Cruces, 

 N. Mex., 400 miles farther south and 2,500 feet lower, began to hatch 

 on April 10, though kept in a cool room. 



The excess of moisture that prevails in Washington might be sup- 

 posed to account for the premature appearance of the larvae in that 

 city, but the atmosphere at Las Cruces is probably as lacking in 

 moisture as is that in northern New Mexico. In both these instances 

 the change of altitude may have had some importance as a factor in 

 hastening the larval emergence. Several clusters of eggs were under 

 observation and the young larvae appeared to have some trouble in 

 hatching, but when the writer moistened the egg with warm water 

 the larvae in the shells became much more active and seemed to be 

 able to gnaw their way through the shell without difficulty. This 

 shows the probable effect of warm showers on the range in facilitat- 

 ing the hatching and perhaps preventing many fatalities among the 

 unhatched larvae. 



The interior of the egg at oviposition is filled with a thin reddish- 

 brown fluid. As the embryo develops this fluid thickens and becomes 

 less noticeable until it has nearly disappeared, when the larva emerges. 



