INVESTIGATION OF LIFE HISTOKV 



23 



One female beetle receivod rroiii Europe in July, 1907, was kept 

 uuclcM- observation at tbo laboiatoiy for two years, so that the h'Ui^th 

 of life may normall}' be considerably longer. 



Nearly one-half of the beetles reared from eggs in 1907 that emerged 

 from the earth in the spiingof 190S survived the summers of 1908 and 

 1909, and went into liibernation in the fall. Tliis serves to illustrate 

 the prolonged period throughout which accurate records must be 

 ke])t, antl the care with which the work must be conducted in order to 

 secure correct data. 



Duiing the summer of 1910 measurements were made of 12 freshly- 

 laid eggs and the same number of larva^ on entering each stage, and 

 these notes are included in the descrij)ti<)ns of stages which follow. 



THE EGG. 



Twelve fresh eggs gave the following average measurements: 

 Length, 5.2 mm., width, 2.4 mm. They are somewhat elliptical in 

 form, with a slight taper toward one end. The color is white, with 

 a faint j^cllowish tinge. They vary somew^hat in size and form and 

 before hatching often become somewhat kidney-shaped. 



The time spent in the egg stage is from 3 to 10 days, and depends 

 largely on the temperature. Careful observations on 2,000 eggs that 

 were laid from May 15 to August IS, 1908, are summarized as follows: 



Table III. — Duration of the egg stage in Calosoma sycophanta. 



Egg stage. 



Number of eggs in — 



May. 



June. 



July. 



August. Total. 



3 days.. 



4 days.. 



5 days.. 



6 days.. 



7 days.. 



8 days.. 



9 days.. 



10 days. 



78 

 605 

 164 



32 



8 



75 



444 

 451 

 36 



529 

 1,059 

 226 

 71 

 17 

 6 

 4 



The eggs recorck'd as hatching in May were securecl from females 

 that were taken from hibernation in March, April, and May and fed 

 in the laboratory. Oviposition seldom takes place under natural 

 conditions in the month of May. 



The average length of time spent in the egg stage, based on the 

 hatching each month during the summer, was: May, 7 days; June, 

 5.2 days; July, 4.4 days; and August, 4 days. 



The table also shows that 4.4 per cent of the eggs laid in 1908 

 hatched in 3 days, 26.4 per cent in 4, 53 per cent in 5, 11.3 per cent 



