ART. 23. BLISTER BEETLE TRICRANIA PARKER AND BOVING. 6 



1917 emergence in large numbers occurred on April 12; in 1920, 

 this did not occur till April 21; and in 1921 large numbers were 

 present on April 3 and 4. In each year a few individuals emerged 

 earlier than the dates given above and a few stragglers came out 

 later, but our observations indicate that the time of maximum 

 emergence covers a period of only one or two days. 



Mating occurs coincident with emergence and oviposition begins 

 immediately unless delayed by an unfavorable change in the weather. 

 The female crawls beneath some object lying loose upon the ground 

 and fastens her eggs in a mass to the under side of this object. In 

 the present investigation eggs were found chiefly on the under side 

 of bits of dried cow's dung (see fig. 42). They were also found un- 

 der loose stones and in one case on the under side of a clam shell, 

 Venus mercenaria Linnaeus, lying in the field. The eggs (fig. 22) 

 are glistening white and are coated with a sticky substance that 

 causes them to adhere together in a mass. They vary somewhat in 

 size; of those measured in 1920 the average was 0.8 mm. in length 

 by 0.32 mm. in breadth and in 1921, 0.83 mm. in length by 0.315 mm. 

 in breadth. The female being wingless does not wander far from 

 the point of emergence from the ground and having selected a place 

 to deposit her eggs remains, if she is not disturbed, in that place 

 till oviposition is complete, shortly after which death follows, due 

 to exhaustion, since little, if any food is taken in the adult stage. 



The number of eggs laid by each female is large and the period of 

 oviposition, as observed in the laboratory, covers about two weeks. 

 Early in the morning of April 21, 1920, two unfertilized females 

 were taken in the field and permitted to mate in the laboratory. 

 They were then put in separate cages suitable for oviposition. Eggs 

 were present in both cages on the morning of April 22, but no count 

 was made till April 27. On this date female No. 1 had deposited 788 

 eggs and No. 2 had deposited 1,020. From this date forward daily 

 counts were made with the following results: 



No. 1 had deposited— Eggs. No. 2 had deposited— Egga. 



April 28 53 April 28 



April 29 35 April 29 192 



April 30 2Q April 30 56 



May 1 9 May 1-4 



May 2 May 5 27 



May 3 17 May 7, the beetle died. 



May 4 



May 5 5 



May 9, the beetle died. 



Thus in the case of No. 1 the beetle deposited a total of 933 eggs 

 in a period of 13 days, perishing 4 days after oviposition was com- 

 plete. In the case of No. 2, the female deposited 1,295 eggs in the 



