60 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 94 



newly emerging egg is received between the closed valvulae, and he 

 figures it as being extruded upward and posteriorly from between the 

 dorsal valvulae ; at least, he assures us, this is what we should see 

 "if we could manage to watch a female " during oviposition. If the 

 female grasshopper habitually curves the end of her abdomen forward, 

 as shown in Riley's familiar illustration, the eggs extruded in this 

 way would naturally take the proper position in the nest with their 

 anterior ends upward and sloped toward the exit. Most studies of 

 the egg cavity, however, show that the burrow, when unobstructed, 

 extends obliquely downward and backward from the insect. In this 

 case the eggs must be tilted in a direction opposite that of their first 

 position, namely, with the anterior pole upward and forward, if the 

 young grasshopper is to have an easy escape from the nest. 



Observations by Giardina (1901) on the extrusion of the eggs by 

 females of Pamphagus marmoratus, which oviposited on the bottoms 

 of cardboard boxes in which they were confined, seem to show that 

 each egg is revolved through an angle of 45 ° as it leaves the ovipositor. 

 Giardina observes that each egg issuing from the oviduct is conducted 

 by the egg guide posteriorly and upward into the ovipositor, where 

 it is at first received and held in this position between the ventral 

 valvulae ; but at this time the upper and lower valvulae are wide open, 

 and the prongs of the lower valvulae are somewhat separated. Now, 

 however, the valves suddenly close, and the egg is thrust between the 

 dorsal valvulae, where it remains suspended until the arrival of the 

 next egg, which causes the first to take a horizontal position with the 

 posterior pole directed backward. Finally, with the advent of a third 

 egg, the first, already liberated from the ovipositor, receives another 

 push, which tilts it into a third position in which the anterior pole is 

 directed upward and forward, i. c, obliquely toward the upper wall 

 and the exit of the nest (fig. 23 F). 



The issuing eggs are always accompanied by a large amount of 

 viscous frothy material, which soon hardens and forms the much- 

 vacuolated mass enclosing the eggs, known as the " egg pod." The 

 foamy nature of the egg covering is said to be imparted to the liquid 

 fresh substance by movements of the valvulae. The female Acrididae 

 lack the usual accessory glands of the genital apparatus that ordinarily 

 form whatever adhesive or covering material is extruded with the 

 eggs ; the substance of the acridid egg pods is produced in long glandu- 

 lar diverticula of the anterior ends of the large calyces of the lateral 

 oviducts, and is discharged with the eggs through the gonopore. 



