4 J. T. PATTERSON 



down and backward. With the aid of the binocular micro- 

 scope and strong transmitted light one can easily observe the 

 egg passing down the lumen of the ovipositor. The egg is forced 

 out bj^ rhythmic pulsations of the abdomen. As soon as the 

 egg is deposited, she withdraws the ovipositor, remains motion- 

 less for a second or two, rubs the pair of hind legs together and 

 then proceeds to search for another egg. The act of oviposition 

 varies in time from two to as long as fifteen minutes. If only 

 a few eggs are present on the leaf, she may in time return and 

 lay again in the same egg. The number of eggs deposited at 

 one oviposition is either one or two. My records show that in 

 about two times out of three two eggs are deposited. 



The parasitic egg may be deposited in any part of the host 

 egg or embryo, but only those which become included in the 

 tissues of the embryo are able to complete development. The 

 egg develops whether fertilized or not. Eggs laid by virgin 

 females always produce male broods, but broods arising from 

 eggs laid by fertilized females are nearly always mixed. 



The process of maturation is completed in one and one-half 

 hours after the egg is deposited. Cleavage then follows, and 

 the polygerm stage is reached in about seventy-two hours. The 

 polygerm is composed of a number of primary masses, each of 

 which consists of a group of embryonic cells surrounded by a 

 nucleated membrane. The primary masses multiply, by con- 

 strictions of this membrane, to produce secondary masses, and 

 these in turn divide to form tertiary masses. Further divisions 

 follow and the entire polygerm becomes a very complex structure. 

 The tertiary mass stage is reached in from seven to nine days. 



The tertiary divisions produce what I have called compo- 

 nents. These become scattered throughout the body cavity of 

 the caterpillar through the dissociation or fragmentation of 

 the polygerm. The tertiary components form centers for fur- 

 ther multiplication, or for the formation of groups of sexual 

 embryos. The sexual embryos begin to form on the fifteenth 

 day and reach the free larval stage sometime between the twenty- 

 second and twenty-fourth days. Pupation occurs on the twenty- 

 eighth day, and the adult insects emerge on the forty-seventh 

 day. 



