72 



The Rocky Mountain Locust. 



side rows to be pushed quite so far down as the two inner 

 rows, and for the very same reason the upper or head ends of 

 the outer rows are necessarily bent to the same extent over 

 the inner rows, the eggs when laid being somewhat soft 

 and plastic. There is, consequently, an irregular channel 

 along the top of the mass (Fig. 9, c), which is filled only 

 with the same frothy matter which surrounds each egg, 

 which matter occupies all the other space in the burrow 

 not occupied by the eggs. The whole plan is seen at once 

 by a reference to the accompanying figure, which represents, 

 enlarged, a side view of the mass within the burrow, (a), 

 and a bottom (b) and top (c) view of the same, with the 

 earth which adheres to it removed. 



DOES THE FEMALE FORM MOKE THAN ONE EGG-MASS ? 



Whether the female of our Rocky Mountain Locust lays 

 her full supply of eggs at once, and in one and the same 

 hole, or whether she forms several pods at different 

 periods, are questions often asked, but which have never 

 been fully and definitely answered in entomological works. 

 It is the rule with insects, particularly with the large 

 number of injurious species, belonging to the Lepidoptera, 

 that the eggs in the ovaries develop almost simultaneously, 

 and that when oviposition once commences, it is continued 

 uninterruptedly until the supply of eggs is exhausted. 

 Yet there are many notable exceptions to the rule among 

 injurious species, as in the cases of the common Plum 

 Curculio and the Colorado Potato-beetle, which oviposit 

 at stated or irregular intervals during several weeks, or 

 even months. The Rocky Mountain Locust belongs to 

 this last category, and the most casual examination of the 

 ovaries in a female, taken in the act of ovipositing, will 

 show that besides the batch of fully formed eggs then and 

 there being laid, there are other sets, diminishing in size, 



