250 



FKt 35 



-Cu.ul.i lu burrow of Sphecius, with full-grown larv 

 Iceiliiig — natural size (original). 



of latter 



The particular species of wasp under consideration chooses for bur- 

 rows the dryer and more elevated portions of lawns, especially the 

 slight terraces along the sides of roadways. Experience shows that the 

 species requires comparatively dry ground in which to undergo its 



transformations, 

 J excessive moisture 



inducing mold in 

 the stored Cica- 

 das, many of the 

 specimens un- 

 earthed being de- 

 stroyed by this 

 agent. On the 

 other hand, in dry 

 earth I have found 

 Cicadas in excel- 

 lent preservation, 

 wliich had evidently been placed there a- year previous, but under 

 which the wasp egg had failed, for some reason, to liatch. The 

 burrows consist of a gently sloping entrance, extending for about 6 

 inches, when ordinarily a turn is made at right angles and the excava 

 tion continued 6 or 8 inches further, terminating in a globular cell about 

 1^ inches in diameter. Frequently a number of branches leave the 

 main burrow at about the same point, and terminate, after a length of 

 6 or 8 inches, in cells similar to the one described. More commonly, 

 however, the branches leave the main burrow at irregular intervals. 

 The different types of burrow are shown in the illustration, (Fig. 33) e 

 representing the entrance and c the cell. The cells, which are remark- 

 ably uniform in size and shape, contain one or sometimes two Cicadas, 

 those stored with two being on the whole the more numerous. In the 

 cells containing two Cicadas the larva acquires larger size, and as the 

 female wasp is a good deal larger than the male, this would indicate 

 that one Cicada only is required for the latter and two for the former, 

 though I have no idea that the amount of nourishment influences the 

 sex (a favorite theory with some naturalists) for I believe that sex is 

 predetermined in the egg. 



The exceedingly delicate, pure white, elongate-ovoid egg of this spedes 

 is deposited in such a position as to be covered by the median thigh of 

 the Cicada. (See Fig. 34.) In hatching, the larva does not emerge from 

 the skin of the egg, but merely protrudes its head and begins at once to 

 draw nourishment from between the sternal sutures of the Cicada. (See 

 Fig. 35.) The egg requires but two or three days to hatch, and the 

 larval life is very brief, not much exceeding a week. The general 

 form of the mature larva is shown at Fig. 30 a. It possesses great 

 extensile and retractile power, which enables it to thoroughly explore 

 and exhaust the body contents of its prey. At full growth it measures 



