36* 



THE AMEBIC AN NATURALIST [Vol. XL V 



emerges as a winged insect ; probably the male does not 

 overwinter. But the female neither forsakes her bag 

 nor acquires wings, she is impregnated by the male 

 within her bag. Each female produces a large number 

 of small eggs but does not oviposit, for she dies within 

 her bag and her dead body becomes a case for the eggs ; 

 at her death her viscera change into a soft cottony mass 

 that acts as a further protection for the eggs. Among 

 some 200 cocoons collected on November 24 I found 

 about half a dozen in which the egg case, the degenerate 

 female, was still living. This species is then a very fav- 

 orable insect for obtaining eggs and early embryos in 

 large abundance during the colder season of the year, 

 and should prove a valuable object for experimentation. 1 

 The controls were kept within their cocoons out-of- 

 doors, and hatched in the end of May. In the experi- 

 ments sometimes the eggs (in early embryonic stages) 

 were removed from the egg cases, sometimes kept in 

 them. 



A. Experiments ivith Sunlight 

 Direct Sunlight. — Lot no. 77, collected January 4, con- 

 sisted of egg cases placed in closed dry bottles in the 

 south window of a warm room (21° C). 77C, kept three 

 weeks in this sunlight, did not hatch; 77A, an untimed 

 period in sunlight, hatched. Lot 78, collected January 

 4, consisted of freed eggs in corked vials without mois- 

 ture, with similar exposure to the light; they were di- 

 vided into four lots, placed in the sunlight for 3, 7, 10 

 and 14 days respectively, and all hatched about March 1. 



Direct Sunlight behind an Alum Heat Filter.— -Four 

 lots of freed eggs (nos. 51, 53, 49, 50) collected January 

 4 were used, placed in the sun behind a heat filter for 2, 

 7, 18 and 28 days, respectively, and all hatched in Jan- 



^ 1 A good popular account of this^ species is given by McCook: "Tenants 



figures. But he makes the common mistake of other naturalists in sup- 

 posing that the female oviposits. See also Howard and Chittenden, circular 

 No. 97, U. S. Department of Agriculture, 3908. 



