234 ILLINOIS ACADEMY OF SCIENCE 



noted that the handkerchief in which it had been carried was 

 sprinkled with minute black eggs. Further observation of the 

 fly revealed the fact that the eggs were forcibly discharged 

 from the ovipositor in extremely rapid succession, not unlike 

 bullets from a rapid-firing gun. The eggs when first deposited 

 are coated with a sticky substance which causes them to adhere 

 to whatever they hit or fall upon. 



The following day some of the trees in the grove were 

 banded with narrow strips of clean white paper. After a 

 brief period several flies appeared hovering over the surface 

 of the bark in the same manner as observed during the pre- 

 vious day. This time, however, with the aid of the white 

 paper strips, their actions were easily interpreted. By watch- 

 ing closely as the flies flew over the paper strips, one could see 

 the eggs appear upon the paper as minute black specks 

 sprinkled in irregular rows. An examination of the bark of 

 these trees showed the leeward side of each tree to be literally 

 sprinkled with hundreds of thousands of eggs. 



The eggs contained in the handkerchief numbered 2,300. 

 All of these were deposited by a single female in a period of 

 not over forty-five minutes. Other counts made show that a 

 female fly may deposit as high as 3,977 eggs. The eggs are 

 very minute, measuring 0.18 mm. in length and 0.15 mm. in 

 width. They are slightly compressed and pear-shaped in out- 

 line and are of dull black color. Their period of incubation 

 is thirty-two to thirty-three days.* 



*For a detailed description of the larvae and other stages see King, J. L., 1916, 

 Observations on the Life History of "Pterodontia flavipes," Gray. Annals Ent. Soc. 

 Amer. Vol. 9, pp. 309-321. 



