102 



BULLETIN 417, U. S. DEPARTMENT OF AGRICULTURE. 



arranged the same a> in C. frigidum; the color, however, is black. Legs small and 

 spiny, tarsi bearing two claws. The anal proleg is stout and covered with numerous 

 short hairs. The under surface is of a purer white than in C. frigidum, but bears 

 similar markings. The latter resemble those of the preceding species in form and 

 arrangement, but are slightly darker in color. The spots composing the first lateral 

 row are -more elongated and all the ventral spots are somewhat larger than in the pre- 

 ceding species. The time spent in this stage is about one month, of which about 

 three weeks are passed in feeding. When full grown the larva burrows into the 

 groimd to a depth of several inches, and alter preparing a cavity throws off its skin 

 and goes into the pupal stage. 



LENGTH OF TIME REQUIRED TO COMPLETE LARVAL STAGE. 



From several feeding records kept of larvae that hatched between 

 June 20 and 24, 1909, it was possible to secure information on the 

 length of time required to complete the different larval stages. It 

 was found at that time of year that an average of 3 days was required 

 to pass the first stage, 5 days for the second, and 12 days for the third, 

 or a total of about 20 days between hatching and cessation of feedmg. 

 No notes were secured with this series of larvae as to the time when 

 feeding ceased and pupation began, but observations on larvae in 1911 

 showed that 6 days were spent in the prepupal stage, 



Some data secured in 1912 show that from 3 to 5 days were required 

 for larvae to complete the first stage, 4 to 6 days for the second, and 

 12 to 17 days for the third. A fair average for these would be 4 

 days for the first stage, 5 for the second, and 15 for the third, or a 

 total of 24 days for the active feeding period. These larvae hatched 

 May 20 to May 28 — much earlier in the season than those referred to 

 under 1909 when the weather was cooler, and this wholly or in part 

 explains the longer time required to complete the growth in 1912. 



FOOD CONSUMED BY LARVAE. 



The most natural food of these beetles and their larvae is cutworms 

 but it was not always convenient to collect these in sufficient num- 

 bers for the feeding experiments, so caterpillars of Porthetria dispar 

 and Malacesoma americana were used. A series of individual 

 records was kept in 1909 and 1910 with caterpillars of these species 

 as a source of food supply. In 1911 a series was kept, feeding pupae 

 of M. americana only, after the cocoons had been removed. 



Table 24. — Food eaten by larvae of Calosoma calidum, 1909-10. 







Malaco- 











Malaco- 











soma 



Porthe- 









soma 



Porthe- 









ameri- 



tria 









ameri- 



tria 





Date 

 hatched. 



Date 



cana 



dispar 





Date 

 hatched. 



Date 



cana 



eiispir 





ceased 



cater- 



cater- 



Total. 



ceased 



cater- 



cater- 



Total. 



feeding. 



pillars, 



pillars, 





feeding. 



pillars. 



pillars, 









fifth and 



sixth 









fifth and 



sixth 









sixth 



stage. 









sixth 



stage. 









stages. 











stages. 







1909. 











1910. 











June 20 



July 8 



110 



13 



23 



Mar 29 



June 22 



9 



1 



10 



23 



12 



4 



13 



17 



June 2 



24 



10 



5 



15 



23 



12 



3 



16 



19 



2 



22 



9 







9 



24 



13 



1 



21 



22 



7 



30 



7 



4 



11 



24 



16 



3 



20 



23 



7 



28 



7 



3 



10 



24 



17 



1 



13 



14 



7 



28 



13 



5 



IS 













7 



30 



6 



v 



14 



Two of these caterpillars were in the third stage. 



